Healthy Homes Issues and Answers

All of us want to live and raise children in a healthy home.  This searchable CD has been created to provide you with information to help you create that healthy home for yourself and your family.  It provides information to help you determine if your home is healthy and provides educational resources to make any needed improvements to get you to a healthy home. Some issues may require you to seek help in addressing and overcoming them.  This CD also provides a list of organizations that you can contact to get that help. 

This resource was produced by Mark Pierce, Extension Associate, and Joseph Laquatra, Professor, of the Department of Design and Environmental Analysis, College of Human Ecology, Cornell University. Funding was provided by the U.S. Department of Housing and Urban Development through the Healthy Homes Partnership, Auburn University, Laura B. Booth, National Coordinator.

Just exactly what is a healthy home?  The National Center for Healthy Housing has identified seven factors that are present in all healthy homes.   A healthy home is:


Step 1 to a Healthy Home, Keep it Clean

General cleaning tips and information:

Step 2 to a Healthy Home: Keep it Contaminant Free

Step 3 to a Healthy Home:  Keep it Dry



Step 4 to a Healthy Home: Keep it Maintained



Step 5 to a Healthy Home: Keep it Pest Free


Step 6 to a Healthy Home:  Keep it Safe


Step 7 to a Healthy Home: Keep It Well Ventilated


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STEP 1: A Clean Home is a Healthy Home

Why a clean home is an important step toward a healthy home
Houses that are kept clean will help reduce family members’ exposure to many indoor pollutants such as bacteria, lead, and allergens like dust mites.  A neat, clean house is also less inviting to mice, rats, and other pests.  And a tidy house is also a safe house.  Toys, reading materials, shoes, and other items left on floors can create tripping hazards, especially if left on stairs. 

A clean house controls allergens  
House dust mites are tiny bugs, too small to be seen by the naked eye.  They feed on shed human skin cells.  The fecal pellets of dust mites contain potent allergens and asthma triggers.  If your eyes start to burn and water when you stir up dust in your home or when you make a bed, you are likely having an allergic reaction to dust mite allergens.  Regular cleaning of your house using proper techniques can easily keep your home free of many allergens, including those from dust mites

A clean house reduces children’s exposure to lead
Another common component of household dust is lead.  Older homes, those built prior to 1978, often contain lead painted surfaces.  Paint chips and dust from friction and impact surfaces as well as painting and remodeling activities are often the source of lead in these older homes.  But newer homes are not completely immune to lead contaminated household dust.  Until 1986 gasoline used by motor vehicles contained lead additives .  When catalytic converters became required on cars and trucks, lead additives were removed from gasoline because lead destroys catalytic converters.  But until that time, millions of tons of lead were released into the environment along highways and streets across the United States.  Much of this lead settled on lawns and gardens surrounding homes.  When dirt and dust get tracked indoors it often contains some of this lead.  By regularly cleaning your home you help prevent children’s exposure to lead contaminated household dust.  Special cleaning methods should be followed when cleaning surfaces if your home was built prior to 1978.

A clean house helps reduce pests
A clean house also helps to control pests like rats and mice.  They need places to hide and make nests.  Keeping your home free of clutter deprives pests of these hiding places and discourages them from coming into and staying in your home.  Washing dirty dishes and wiping kitchen work surfaces after each meal helps deprive pests of food.  If pests don’t find food in your home, they will not stay.


General cleaning tips and information:
The Kitchen:

Every Day:

Once a week:

Every Three to Six Months depending on condition of surfaces:

At least once annually, more if needed:

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Cleaning methods for controlling allergens in your home
Household dust contains many different compounds, including pieces of human skin, insect parts, rodent and insect feces, plant pollen, textile fibers, and many other items.  Exposure to these compounds and the potential for inhaling them when dust becomes airborne is not healthy.  Control household dust by vacuuming floors once or twice weekly with a HEPA vacuum or a regular vacuum fitted with a HEPA bag.  HEPA is an abbreviation for high efficiency particulate air filter.  These types of bags can trap almost all dust sucked up by a vacuum and therefore keep it from being blown back into the air via the vacuum exhaust port.  HEPA filters for most types of vacuums can be purchased at vacuum cleaner supply outlets.  Note that adding a HEPA bag to a conventional vacuum cleaner is not always as effective as using a HEPA vacuum cleaner.  Because of loose fittings or connections, conventional vacuum cleaners can release dust into the air while they are operating, even if a HEPA bag is used.

Cleaning strategies for controlling dust mites
House dust mites often live in mattresses and pillows.  Washing pillow cases and sheets once per week in hot water (130 degrees or hotter) can help control them.  Placing allergy proof encasements over pillows and mattresses is also a very effective control measure.  These encasements should also be washed once a week in hot water.


Cleaning surfaces in older homes that are likely to contain lead-based paint
Contact with lead contaminated dust is one of the most common ways children get poisoned by lead.  Keeping painted surfaces in your home well maintained and clean can reduce children’s exposure to this poisoning risk.  Follow the special cleaning tips listed below to clean household surfaces and reduce children’s exposure to dust. 

Cleaning uncarpeted floors:

Use the three-bucket method when mopping floors:

Cleaning window stools, sills and other woodwork:

Cleaning carpeted floors and rugs to control lead containing dust:
Obtain a HEPA filter for your vacuum.  A vacuum attached with a HEPA filter will trap almost all minute dust particles that may contain lead.  A standard vacuum without a HEPA filter tends to spew significant amounts of fine dust from its exhaust port, making it a poor choice for housecleaning in older homes likely to contain lead.


Special Cleaning

Cleaning up a broken fluorescent light
Compact fluorescent and tube type fluorescent lights all contain a small amount of mercury sealed within the glass enclosure.  So it is best to use extra care when storing and changing fluorescent lights.  If you do happen to break a fluorescent light follow the cleanup instructions listed below to minimize any mercury contamination.

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Step 2: A Contaminant Free Home is a Healthy Home


What is asbestos?
Asbestos is a mineral that has been mined and used in products in the United States since the late 1800’s.  Asbestos has been used as an insulation material in buildings and asbestos fibers have also sometimes been used to reinforce construction products.  For example, it was sometimes used in siding and roofing products.  It was also added to some joint compound products used to finish gypsum wallboard.

If asbestos containing products are disturbed, tiny fibers can be released into the air.  If inhaled, those fibers can become trapped in the lungs.  Since the fibers are mineral-based and very durable, the body cannot break them down.  Once inhaled, they remain in the lungs for decades.  The trapped fibers irritate the lungs, and over time cause severe scarring of the lung tissues.  This scarring causes some very serious diseases.

Health effects from exposure to asbestos
People who have been exposed to asbestos have an increased risk of developing lung cancer; mesothelioma, a cancer of the lining of the chest and abdominal cavity; or asbestosis.  Asbestosis is a disease related to the scarred lung tissues caused by inhaled asbestos fibers.  Asbestosis is primarily a chronic respiratory disease that causes reduced lung functioning and shortness of breath with little or no physical exertion.  Risk of developing lung cancer or mesothelioma increases with the number of asbestos fibers inhaled, and that risk increases for people who smoke.  The risk of developing asbestosis is highest for people exposed to large amounts of asbestos over long periods of time.  The symptoms of these diseases do not develop until 20 to 30 years after initial exposure to asbestos.

While most people exposed to high levels of asbestos fibers work in industries where they are exposed to asbestos regularly, there is some concern that people can be exposed to asbestos in their homes.  Before the 1970s it was not known that asbestos posed a health risk, so it was often used in many products commonly found in homes.  The list below provides information about what products are most likely to contain asbestos and how fibers contained in those products could be released.

Sources of asbestos


Asbestos control measures

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Biological Pollutants:

What are biological pollutants?
A biological pollutant is anything that is alive, once was alive or came from a living organism.  For example, live cockroaches would be considered a biological pollutant.  The fecal material left behind from a cockroach (came from a living organism) and the body parts of a dead cockroach(once was alive) are also considered biological pollutants.

Health Effects from Exposure:
Biological pollutants include a vast number of living organisms and their by-products.  Health effects are related to exposure to the specific biological organism and sometimes to the concentration of the pollutant.  For example, exposure to some biological pollutants causes only mild to moderate reactions in allergic individuals (note that exposure to an allergen can be life threatening if it causes an asthma attack in a person who has asthma). 

But exposure to other types of biological pollutants can be very serious for any exposed individual.  An example is Hantavirus.  It is a rare but deadly disease that humans can catch from infected mice.  Infected mice pass the virus to humans via their urine, droppings or saliva.  Anything that puts you or your family in contact with these carries the risk of getting Hantavirus.  To learn more about Hantavirus go to the PDF file, Hantavirus Pulmonary Syndrome: What You Need To Know

There are two important control methods for all biological contaminants:

1) Control environmental conditions within your home so it is less inviting to these living organisms.  To learn more about discouraging pests from entering your home, see the section Keep Your Home Pest Free
2) Use good cleaning habits and methods to remove compounds left behind by living organisms that can cause health problems for people.  Good cleaning habits also remove favorable environmental factors that support pests.


Biological contaminants commonly found in homes




Cockroaches are insects that range in size from about ½ to 1-¼ inches long, depending on the species of the cockroach.  They are nocturnal and run  to hiding places when exposed to light.  They are common pests in homes where they eat food residues on dirty plates, pet food, food wastes in garbage, etc.   They leave chemical trails in their feces that other cockroaches can follow to find food, water, hiding spaces and other cockroaches. 

Cockroaches often live in and around sewers and drains, and can spread bacteria they carry on their bodies to humans when they crawl across kitchen surfaces and dishware stored in cabinets. 
The presence of cockroaches in homes is also associated with asthma and allergy of occupants of those homes.  The fecal pellets, saliva, and body parts of cockroaches are strong allergens.

The best cockroach control strategy is to discourage them from entering and staying in your home by depriving them of the environmental conditions they need for survival.  Do this by keeping your home clean and keeping your home dry.
To learn more about controlling cockroaches in your home, see the Integrated Pest Management Fact Sheet: Found a Cockroach (Saw a Gazillion?) Don’t Panic

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Dust Mites


Dust mites are very tiny and invisible to the human eye.  They live in bedding, mattresses, carpeting, and upholstered furniture in our homes and eat tiny pieces of organic material, primarily pieces of shed human skin cells.    

The fecal pellets of dust mites contain an enzyme that is a potent allergen.  In fact, most people will experience some type of allergic reaction when exposed to significant amounts of dust mite allergen.  Allergic reactions may be relatively mild with symptoms such as watery and burning eyes, sneezing and itchiness.  Highly sensitive individuals experience more severe respiratory reactions.  And exposure to dust mite allergens is a significant asthma trigger.

A regular cleaning regimen to control dust, especially in bedrooms, is  one of the best strategies for controlling house dust mite populations.  Washing of bedding in hot water, 130 degrees, once per week is another major control strategy.  Severely allergic individuals and people with asthma may also want to purchase non-allergenic mattress and pillow covers.  In the Cleaning section, see the section on cleaning strategies for controlling dust mites.

Mold/Mold Spores
Molds are a group of organisms that are very common in the outdoor environment.  They are vitally important because they are one of the few organisms that can break down cellulose-based materials such as leaves and trees.  But if molds are allowed to grow in our buildings, they can damage materials within them and also create negative health effects for building occupants.

If mold is allowed to grow inside a home, it can produce allergens and in some cases toxic substances called mycotoxins.  Inhaling mold spores produced by a mold growth can cause allergic reactions such as sneezing, runny nose, and red eyes.  And for people with asthma that are also allergic to mold spores, exposure can cause an asthma attack.

Like so many other  biological contaminants, the best strategies for controlling mold growth in your home are to keep your home clean and keep it dry. 

To learn more about mold in buildings, how it gets in, and how to keep it out, see the fact sheet: Mold Information Sheet

If you already have a large area of mold growing in your home and want to learn how to hire the right firm to clean it up, see the fact sheet: Hiring a Mold Remediation Contractor

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Carbon Monoxide

What is Carbon Monoxide?
Carbon monoxide is a deadly, poisonous gas that has no odor or color.  Since you cannot see or smell this gas it is especially dangerous because you may not know it is present in your home until it is too late.  Carbon monoxide gas is produced whenever a fuel is burned.  Basically anything that burns will produce carbon monoxide gas.  While heating appliances that burn fuel efficiently produce less carbon monoxide than inefficient heating appliances, all will produce some carbon monoxide.  This includes all of the following heating and cooking fuels used in our homes:

In addition to the above sources, carbon monoxide is also produced from any internal combustion engine.  That includes all of the following:

Even a burning cigarette, cigar or pipe will produce a small amount of carbon monoxide gas.


How Does Carbon Monoxide Get Into Homes?
Most houses in the United States have at least one combustion appliance located within the home, and many have several.  For example, a house may have a natural gas-fueled furnace and water heater in the basement, a natural gas-fueled clothes dryer in the laundry room, and a natural gas-fueled oven in the kitchen.  The same house may also have a wood fireplace or wood-burning heating stove.  If any of these appliances have not been installed correctly, have not been routinely inspected and maintained, or are not operated correctly, they have the potential to release carbon monoxide gas directly into the house. 

A vehicle left running in an attached garage, even with the garage door open often results in carbon monoxide from the vehicle exhaust getting into the house.  Small engines such as those on lawn mowers or emergency generators can release very high levels of carbon monoxide gas, because these engines seldom burn fuel very cleanly.  So, if these devices are operated inside a garage, even with the garage doors open, they can very quickly build up deadly amounts of carbon monoxide gas.


Protecting your Family and Yourself from Carbon Monoxide Gas
There are two primary methods for protecting you and your family from exposure to carbon monoxide gas:
1) Take steps to prevent carbon monoxide gas from ever getting into your home.
2)  Install carbon monoxide detectors to warn you and family members if it does get into your home.

Keeping Carbon Monoxide out of Your Home
Most residential combustion appliances vent the gases from the combustion process directly to the outdoors through flues and chimneys.  When the venting process works and the combustion appliances are operating correctly, any carbon monoxide produced by these appliances is directed out of the home.  But if a furnace or water heater is not working correctly, then the gases may get into the house instead of being vented to the outdoors. The best way to make certain this never happens is to have your heating appliances inspected, cleaned and tuned regularly by a qualified heating technician. 

Some combustion appliances in homes are not vented to the outdoors.  The most common example is a gas oven and/cook top.  This is the primary reason that kitchens should have range hoods vented to the outdoors.  They provide a method to exhaust the combustion fumes from the oven and cook top out of the house before concentrations can build up to unhealthy levels.  Note that recirculating range hoods that simply move air through a filter contained in the hood and then back into the kitchen are not effective at removing combustion gasses.

While it is possible to purchase unvented heating appliances like portable kerosene heaters and gas space heaters and fireplaces, this is not recommended.  While these types of heaters burn fuel very efficiently when operating correctly, they do emit combustion products directly into your home.  Many people do not realize that water vapor is a combustion product.  Unvented heaters can generate the equivalent of several gallons of water a day in the form of water vapor. This moisture can have negative effects for both the building and for indoor air quality.  For more information on moisture problems and unvented heaters see the section, Keep Your Home Dry: Use Sources of Moisture in the Home

Install Carbon Monoxide Detectors
Any home with a combustion appliance, fireplace, wood-burning appliance, or any other appliance in the home that produces a flame, should have a carbon monoxide detector.  The only homes that do not need carbon monoxide detectors are all-electric-homes. 

According to the Consumer Product Safety Commission, only CO alarms that meet the requirements of the current UL 2034 or CSA 6.19 safety standards should be used.

A CO alarm should be installed within 15 feet of every separate sleeping area in the home.

To obtain more information about carbon monoxide, see the U.S. EPA publication, Protect Your Family and Yourself from Carbon Monoxide Poisoning.

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Environmental Tobacco Smoke

What is Environmental Tobacco Smoke (ETS)?
Environmental tobacco smoke, also known as second-hand smoke, is the exhaled smoke from a cigarette, cigar, or pipe smoker.  It is also the smoke that drifts from the burning end of a cigarette, cigar or pipe while the smoker is holding them or while they sit in an ash tray.  ETS contains thousands of chemicals, and many of those are known to cause cancer.

Health Effects of Exposure to ETS:

Preventing exposure to ETS

Want help to quit smoking? 
Go to
See the PDF file:  Help for Smokers and other Tobacco Users

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What is Formaldehyde and How Does it get into Houses?
Formaldehyde is a chemical that produces a gas with a very distinctive odor that most people can smell even at moderate levels of concentration, 0.05 to 1 part per million.  If you remember the smell of the liquid that frogs were preserved in before dissection in high school biology class, you know what formaldehyde smells like.  It is one of the most widely used chemicals in the United States.  It is used in making many types of products for homes. 

Much of the formaldehyde produced in the United States each year goes to make urea and phenol resins.  These resins are used to make adhesives, bonding agents, fabrics, coatings, and paper.  Phenol formaldehyde resins are most often used to glue wood layers together when making exterior grade plywood and oriented strand board (OSB).   Urea formaldehyde resin is most often used to make particle board, hardwood plywood, and medium density fiberboard (MDF).  Hardwood plywood is used to make wall paneling, furniture, cabinets, and flooring.  Particle board is often used as a floor underlayment in homes before carpeting or another type of finish flooring is installed.  It also is used to make furniture and kitchen cabinets.  MDF is most often used to make furniture and cabinets.

Products made with urea formaldehyde resin emit much higher levels of formaldehyde gas than those produced from phenol formaldehyde.  Temperature and humidity levels also affect how much formaldehyde is released from urea formaldehyde-based products.  Higher temperatures and relative humidity levels mean more formaldehyde is emitted. 

Urea Formaldehyde Spray Foam Insulation
During the 1970s: formaldehyde was also a primary component in a type of spray foam insulation called Urea Formaldehyde Foam Insulation (UFFI).  It was used to insulate walls and ceilings in many new homes during this period.  Studies have shown that immediately after these homes were insulated with UFFI, indoor levels of formaldehyde were fairly high.  Usually formaldehyde levels dissipated within a few weeks of the installation, and formaldehyde concentrations returned to typical ambient levels. 

Is it a problem if your home was insulated with UFFI?
If your home was insulated with UFFI during the 1970s it is highly unlikely that it is off-gassing any formaldehyde over 30 years later.  This is because studies show that as urea formaldehyde-containing products age, the formaldehyde levels they release decrease.  Therefore, homes in which UFFI was installed many years ago are unlikely to have high levels of formaldehyde now.

Health Effects from Exposure to Formaldehyde
Exposure to moderate levels of formaldehyde can cause watery and burning eyes, stuffy nose and sore throat.  Sensitive individuals may experience symptoms at even lower concentration levels, even below the threshold limit for smell.  At higher concentration levels formaldehyde can cause irritation of the lung’s airways.  And at high concentration levels, coughing, wheezing, and chest tightness can occur.  It has also been shown to cause cancer in animals, and may cause cancer in humans. 

How to Limit Your Exposure to Formaldehyde


stamp1 stamp2
Figure 1: Sample formaldehyde emission certification stamp from the Composite Panel Association. Figure 2: Sample formaldehyde emission certification stamp from the Hardwood and Plywood Veneer Association.

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What is lead and why is it a health threat?
Lead is a toxic metal that causes many negative health effects, especially for children under age 6.  When lead is absorbed into the body it can damage the brain, kidneys, nerves and blood.  It also causes learning disabilities and behavioral problems.  If enough lead has been absorbed by the body, seizures and even death can occur.

How do children get exposed to lead?
The most common source of lead in and around homes comes from peeling and flaking paint that contains lead.  When lead-containing paint chips get on the floor or in dirt around the outside of a home they crumble and turn into fine dust.  But the lead contained in the paint chip does not go away.  It is still present in household dust and soil in lawns and children’s outdoor play areas.

What steps can you take to prevent lead poisoning?
If your home was built before 1978 there is a good chance it contains some lead-painted surfaces.  Follow the suggestions listed below to help reduce exposure to lead-contaminated dust:

Work “Lead Safe” when doing painting or repair work in any pre-1978 home.  To learn details of how to work Lead Safe see the EPA booklet, Steps to Lead Safe Renovation, Repair and Painting

Special cleaning strategies can also help protect children from exposure to lead contaminated dust:

Vacuum carpets and upholstery regularly to remove any accumulated dust and dirt.   Whenever possible use a vacuum with a high efficiency particulate air (HEPA) filter.  A vacuum cleaner with a HEPA Filter will remove 99.97% of all particles down to a size of .3 microns.   One micron equals 1/millionth of a meter.  A human hair is 100 microns wide.  Compare this with the average vacuum cleaner that filters particles from 30 to 50 microns, and you can imagine how much dust never gets captured by a typical vacuum cleaner.  Since the goal is to capture and dispose of any household dust that may contain lead, you can see how much more effective a HEPA filtered vacuum cleaner is at doing this.  HEPA filters for vacuum cleaners are available at department stores and cleaning supply stores.
To learn more about protecting your children from lead poisoning see the EPA Booklet:  Lead in Your Home: A Parent’s Reference Guide

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Chemical pesticides commonly used in the home are items such as fly spray, rat poison, flea treatments for pets, and lawn and garden pesticides.  These chemicals are designed to sicken and kill insects, mice, rats, and other pests.   However, if used improperly or if over-used, they pose health risks to humans, especially small children. 

A much safer, and often more effective, method for controlling pests is to eliminate the environmental conditions that make your home attractive to them.  To learn more about how to do that, see the Cornell University publication on Integrated Pest Management

Why be concerned about pesticides:
The biggest risk from home pesticide use is accidental poisoning.  Children are the most likely victims.  Accidental poisoning happens in two basic ways:

Tips for safe use of pesticides
The first tip to consider is that the safest method for handling pesticides in the home is to avoid their use as much as possible.  Start out by using non-chemical methods of control, such as those outlined in the section on integrated pest management.  If you do decide that a chemical pesticide is needed to control the pest, follow these tips to control the amount of pesticide residue in your home:

To learn about how to safely store pesticides in your home, see the section on home safety: preventing poisoning
If you want more detailed information on using pesticides in the home, including information about safely choosing, mixing, and applying pesticides see the EPA publication: Citizen’s Guide to Pest Control and Pesticide Safety

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What is Radon?
Radon is a radioactive gas that comes from naturally occurring uranium deposits in the ground.  Because it is a gas, it can be drawn into houses through cracks and other openings in parts of the house in contact with the ground.  Radon gas cannot be seen.  It has no odor and no taste.  This means you cannot tell if radon gas is getting into your home unless you conduct a test to detect it.

Why be Concerned about Radon Gas in Your Home?
Exposure to radon gas in buildings is the leading cause of lung cancer for people who do not smoke.  In addition, exposure to radon gas in buildings increases the chances of getting lung cancer even higher for people who do smoke.

How can you tell if your home has radon gas?
There is a simple, easy-to-use, do-it-yourself test to tell if there is radon gas in your house.  You can buy a radon test kit at hardware stores and other home improvement retail stores.  The test kit comes with simple directions for conducting the test.  Test kits are not expensive.  You may also be able to receive a free or reduced cost test kit from your local health department.
What can be done if test results show your house has radon gas?
Reducing radon gas in a home is not difficult.  A vent pipe is installed into the ground under the house.  This pipe is extended up through the house and through the roof, similar to a plumbing vent pipe.   An in-line fan may be installed on the vent pipe.   If  a fan is needed, it will always be on. It pulls radon from beneath the house, before it has a chance to enter, and exhausts it to the outdoors.  The cost of a radon gas mitigation system depends on many factors, including how your home was built and where it is located, but most homes can be fixed for less than $2,000.

To learn more about radon and how to protect yourself and your family from exposure to the gas, read the brochure,
A Citizen’s Guide to Radon: The Guide to Protecting Your Family and Yourself from Radon

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Volatile Organic Chemical Compounds

What are Volatile Organic Chemical Compounds (VOCs)?
A chemical that is volatile is one that becomes a vapor at normal room temperature.  For example, when you open a can of paint, you immediately smell it.  This is because the chemicals in the paint are volatile.  When the liquid paint is exposed to the air, some of the chemicals in the paint vaporize and enter the air.  Organic chemicals are those that contain carbon, a basic chemical element.  Compounds simply mean that that they are a mixture of more than one chemical element, carbon and hydrogen for example. 

Why be concerned about Volatile Organic (Chemical) Compounds?
Many household products available for use in our homes contain volatile organic chemicals.  Some examples are cleaning products, pesticides, and hobby materials, such as paints and some types of adhesives.  Since these products are volatile, they can then be inhaled.  Inhalation of many VOCs causes negative health effects, especially for young children.  

Why try to Avoid Volatile Organic (Chemical) Compounds?
There are several potential negative health effects related to exposure to volatile organic chemicals.  They range from mild irritation to much more serious conditions (see list below)

Since there is no requirement that manufacturers notify consumers on product labels that the product they are purchasing contains VOCs, consumers must learn what products typically contain them.  VOCs are used in paints, varnishes, wax, cleaning and disinfecting products.  They are also used in cosmetics, hobby products and degreasing products.  Fuels like gasoline, fuel oil, and kerosene also contain VOCs. 

Furniture strippers, turpentine, dry cleaning fluids, paint thinners and nail polish removers contain very high levels of volatile organic compounds.  Most paints, aerosol sprays, furniture oils, shoe care products, carpet cleaners, glues and adhesives, and wood finishing products like varnish, shellac and polyurethane contain moderate levels of VOCs. 

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Methods for Reducing Exposure to Volatile Organic Compounds

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Step 3: A Dry Home Is A Healthy Home

Water is absolutely essential to our basic survival.  We must have clean fresh water for drinking and cooking.  And our lives are made much more healthy and comfortable by having clean water for bathing and cleaning.  Water is so essential to our well-being that we pipe fresh water directly into our homes and pipe waste water out.  But our buildings have very different needs than the people who occupy them.  Water in all its forms, liquid, ice (frozen) vapor (gas) is a killer of our buildings.  Excess moisture in buildings also creates conditions that have a negative impact on indoor air quality.
Consider the following:

Water gets into homes from three basic sources.

1) Use Sources: From the activities of the people living in the home.
People breathe, shower, and cook in homes.  This all creates moisture within the home, usually in the form of water vapor.  We also pipe water directly into our homes for drinking, cleaning, and bathing.  While most of that water is directed back out of the home via drains and drain pipes to either private septic systems or municipal water treatment plants, a certain amount enters the air of the home in the form of water vapor.

We cannot stop moisture from these sources.  But, we can control it and use ventilation to get water vapor out of our house before it has a chance to condense on surfaces and cause a moisture problem.
Other ways occupants may introduce water into their homes: 

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Controlling Water and Moisture at its Source:


2) Maintenance related sources are another source of moisture in a home.  Leaks in water pipes, even very tiny drips that are ignored or undetected, will eventually lead to a moisture problem in the home.  Some other examples of water and moisture getting into homes due to lack of maintenance are leaks in a roof that need to be repaired or replaced.  Dryer vents that have become disconnected are another example. A disconnected dryer vent allows water-saturated air from the dryer directly into the house.

Follow the maintenance tips listed below to help you keep your house dry.

Another part of good maintenance practice in keeping your home dry is to be vigilant to any sources of moisture or water seepage into the walls of your home.  At least once a year conduct a careful inspection of your homes' walls, both inside and out.  Look for any evidence of water intrusion and pay special attention to areas around windows and doors.  Water stains or peeling paint in an isolated spot on exterior walls may indicate a leak.  Peeling paint or spongy wall board on interior walls also indicate a leak.  If a leak is suspected, it may be necessary to remove a few pieces of siding to know for sure. 

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3) Construction related moisture and water intrusion is the third source of excess moisture in homes.  Basically, this is about how well the home was built.  If the builder did a good job of building the house, then the basement or crawlspace always remains dry, even at extra wet times of the year such as the spring when snow melts.  If the builder also installed the roof, windows and doors with correctly detailed flashing, and a drainage plane (felt paper or house wrap) between the exterior siding and the wall sheathing, then no water will be able to get inside the walls during heavy rain storms when wind driven rainwater can get pushed behind the siding.

The first two sources of moisture, those related to use of the home by its occupants and those related to maintenance, are usually fairly simple and inexpensive to control or fix.  Unless the home has been recently constructed and covered by some type of builder warranty, homeowners are almost always stuck with the cost of fixing construction-related moisture problems.  Perhaps the best way to avoid this problem is to never to buy a home with any construction-related moisture problems.  If you are a tenant, then it is the responsibility of the landlord to fix any construction-related moisture problems.

A wet basement or crawl space can be responsible for conducting several gallons of water into the living areas of a home each day. Improper grading around the house foundation and failure to follow good construction practices when building the home’s foundation are the primary causes of wet basements and crawl spaces.  Fixing a wet basement can be as simple as repairing rain troughs and gutters so that rain water gets conducted away from the house.  But, for basements that were not constructed properly, the fix is usually more complex and expensive.  There are firms that specialize in repairing wet basements. 

Another common moisture problem in homes related to poor construction practice is seepage of rain water directly into the walls because of improper flashing at door and window penetrations.  Sometimes leaks are not apparent until rot becomes evident on interior or exterior surfaces.  Good maintenance includes regular inspections of the interior and exterior areas of your home to look for signs of water getting into the walls. 

See the graphic A Properly Constructed Home is a Dry Home to see what construction practices should be followed when any home is built

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Step 4: A Maintained Home is a Healthy Home

Keeping your house or apartment well maintained is important for keeping your home healthy and safe.  If you are a homeowner, this will also protect the money you have invested in your home.  If you rent, notifying your landlord of any maintenance-related problems in your apartment will allow your landlord to address small problems before they grow into larger problems.  Any responsible landlord will appreciate this.  

A house or apartment complex has many systems within it that require monitoring. Routine maintenance of these systems is also required..  As a homeowner or tenant, you do not need to know every aspect and technical detail of all these systems.  But you should know what the basic maintenance requirements are for the various systems and equipment in your home.  You need to know what actions are required of you as the homeowner or tenant, and what items you need to hire a professional for.  If you rent your home, it is your landlord’s responsibility to bring in professionals when needed. 

The following systems and devices within a home require some attention and maintenance by the owner:

Homeowner maintenance tasks consist of regularly inspecting items in the home to make certain they are operating properly and doing the job they were designed to do.  You may not be able to fix problems you find.  But, by regularly inspecting your home, you can identify problems that need to be corrected and call a professional to fix them before they get worse and lead to other more serious problems.  For example, if you make a habit of regularly inspecting a crawl space you might discover that a water pipe has developed a leak.  While you may not be able to fix that leak, you can immediately contact a professional who can.  It is these regular inspections of your home that allow you to discover problems when they are small and easy to fix.  For an inspection checklist, see the Healthy Home Maintenance Checklist

The information below will provide strategies and tips you can use to keep various areas of your home maintained.  This will help keep your home healthy, and it will save you money. 


Managing Household waste and recyclable materials  
Household waste refers to items that are no longer useful and we want to discard.  Examples are food scraps, packaging materials, and broken items that are not repairable. 

Tips for proper and healthy management of household wastes:

Tips for healthy management of recyclables:


Maintaining your homes plumbing system:
Regularly inspect water pipes, drain pipes and kitchen and bath faucets for leaks.  Water leaks can create ideal conditions for mold growth.  Also, pests need fresh water to survive, so water leaks make your home very inviting to mice, rats, cockroaches, and other pests.  Follow tips listed here to catch leaks early and repair them before they create health risks to your family. 

Septic system maintenance
If your home is on a septic system you should have it inspected by a professional at least once every three years.  Most tanks require pumping every 3 to 5 years, but an inspection can verify if that is sufficient. To learn more about monitoring and maintaining your home’s septic system, see the EPA Guide, A Homeowner’s Guide to Septic Systems

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Natural gas, propane and fuel-oil fired heating systems:

Routine maintenance of home heating equipment is critically important for the health and safety of your family.  Every year more than 500 people are killed in their homes from carbon monoxide poisoning.  Many of these poisonings can be prevented if home heating equipment is checked at least once a year by a qualified technician.  Follow these maintenance tips:

Have done by professionals:

You, the homeowner, should:

Solid fuel-fired heating equipment (wood, coal. and pellet stoves)
Solid fuel heating systems such as pellet, coal, and wood stoves are very different from the gas or liquid fuel fired central heating systems most homeowners are familiar with.  While a wood, coal, or  pellet stove can provide an affordable auxiliary source of heat, a stove requires much more attention and work than automated central heating systems.  Solid fuel heating systems require the homeowner to constantly monitor the fuel level in the appliance and to carry the solid fuel and load it into the appliance when needed.  The homeowner must also monitor the combustion air and fuel feed rate and make adjustments when necessary Consider how much extra work you are willing to do before purchasing and having a solid fuel-burning stove installed in your home.

If you currently own a solid fuel stove or plan to purchase one, be certain to follow all manufacturer’s cleaning and maintenance directions.  All of these appliances require cleaning several times per heating season.  Wood burning stoves also often require that the chimney be cleaned once or twice during the heating season.  Solid fuel-burning appliances should also be inspected and cleaned by a professional at least once per year.

Burning firewood, coal and wood, corn or grass pellets will produce carbon monoxide and other pollutants.  Make absolutely certain these types of heating appliances are installed according to all code requirements by a trained professional.


Unvented heating appliances
Natural gas and propane stoves, ovens and cook-tops are unvented combustion appliances.  That is, the fumes from the gas flames in the oven or cook-top burners are emitted directly into the kitchen.  This underscores the importance of an exhaust fan that is ducted to the outdoors, and means maintenance and proper operation of these appliances are very important considerations.  Have natural gas and propane cooking appliances cleaned and tuned regularly by a technician. Dirty or poorly tuned cooking appliances can emit large amounts of carbon monoxide. Never use a gas oven for space heating purposes. Doing so can emit dangerous levels of carbon monoxide.

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Maintenance of Cooling Equipment
Both room and central air conditioners require routine maintenance to keep them operating efficiently, and to maintain good indoor air quality.  Room air conditioners are what most of us call window air conditioners.  They fit into a window and are designed to cool a single room.  A central air conditioner is designed to cool the entire house and uses a series of metal ducts to direct cooled air to each room in the home.  The following list provides some basic tips for maintaining air conditioners.

To learn more about this topic see the Housing Fact Sheet, Maintaining Your Air Conditioner

Maintenance of humidifiers
Energy efficient homes that are properly insulated and sealed do not need humidification.    Therefore, the recommendation is to not install humidification systems or use room humidifiers unless recommended by a health care professional. 

Cool mist humidifiers
Studies done by the United States Environmental Protection Agency (U.S. EPA) indicate that cool mist humidifiers disperse more minerals and micro organisms into indoor air than other types of humidifiers.  If you decide to use this type of humidifier, follow very strict cleaning and maintenance practices.  Cleaning recommendations are listed below:

Steam type room humidifiers
Steam humidifiers, also called vaporizers, boil water to produce steam which is directed into the room air where it increases relative humidity.  Steam humidifiers are often used by people when they have a cold, because medical inhalants designed to reduce coughing can be added to the steam.

Steam humidifiers create fewer indoor air quality issues than cool mist humidifiers.  This is because many pathogens that may be present in the water are killed during the boiling process.  And steam does not transfer as many minerals from the water to the air as cool mist humidifiers do.  But, steam humidifiers use much more electricity than cool mist humidifiers.  It takes a significant amount of energy to boil water.

Steam humidifiers also require careful and routine maintenance and cleaning.  Follow manufacturer’s recommendations carefully if you decide to use a steam humidifier.

Dehumidifiers are used to pull moisture from the air.  They are often used in below-grade basements during periods of hot, humid summer weather.  High relative humidity in basements during summer months can cause condensation to form on cooler below grade foundation walls and concrete slab floors.  By pulling moisture from the air, a dehumidifier lowers relative humidity and prevents condensation from occurring. 

Dehumidifiers Maintenance

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Step 5: A Healthy Home is a Pest Free Home

Household pests like insects and rodents sometimes find their way into our homes.    Common insect pests are cockroaches, flies and fleas.  Recently bedbugs have been finding their way into more and more homes.  Mice and rats are the most common rodents that invade our homes.  If uncontrolled these pests can threaten our health.  They are especially threatening to children’s health. 

Use Integrated Pest Management (IPM) to control pests
Integrated pest management (IPM) is a method for controlling pests that focuses on learning about pest behavior and their preferred environments.  Once this information is obtained it can be used to eliminate the conditions that attract pests to your home.  One of the primary goals of IPM is to eliminate pests as safely as possible.  This means using chemical pesticides only as a last resort.  There are three basic steps to safely eliminating pests with IPM methods:

To learn more about integrated pest management see the Cornell Cooperative Extension flyer:
IPM for Homes:  How to use integrated pest management to uninvite residential pests


Health Problems Related to Insects, Dust Mites, and Rodents in Your Home


Exposure to both cockroaches and rodents is a severe heath risk to people, and especially children, who have asthma.  Cockroach allergens are strong asthma triggers.  Cockroach allergens are small pieces of cockroach bodies and feces.  These allergens get mixed in with household dust; and whenever that dust is disturbed, allergens get launched into the air where they can be inhaled and cause an allergic reaction.  Most people will have some type of allergic reaction when exposed to household dust that contains cockroach allergens, and for people that have asthma this can cause an attack.  Asthma attacks can be life threatening.  Cockroaches create additional health problems because they live and crawl in filthy places so they often spread bacteria wherever they go.

Keeping your home clean and dry are two methods that will help prevent dust mites and cockroaches from coming into your home.

Bedbugs are small insects that feed on the blood of warm blooded animals.  Adult bedbugs are about ¼-inch in length.  Bedbugs are not known to transmit infectious disease; however their bite causes an allergic reaction at the site of the bite.  Bedbug bites look and feel similar to flea bites. Bedbugs have no wings.  They typically get into homes as stowaways on luggage, clothing, bedding, mattresses, boxes, and other items that are moved between homes, apartments, and hotels.  Used furniture, especially bed frames and mattresses, are most likely to harbor bedbugs or their eggs.  Bedbugs can live many months without eating so they often hide in the cracks and crevices of vacant apartments until people move in.  Then they invade the bed during night hours, bite and drink a few drops of blood before again retreating to their hiding place in the wall or floor.

To learn more about bed bugs and how to control them, click on the link below:
Bed bugs are back!  An IPM Answer   (Factsheet from New York State Integrated Pest Management Program and Cornell Cooperative Extension.

House flies can spread diseases like food poisoning and dysentery.  Flies usually feed and lay their eggs on garbage, manure, or carrion.  So, when they get into homes they contaminate food preparation areas and food they land on.  Also, when flies feed they regurgitate their stomach contents onto the food source to liquefy it and make it easier to eat.  Of course, this contaminates any food they land on in your home with the contents of any filthy items they were eating prior to entering your home.  They also defecate on food preparation surfaces they land on, further increasing the threat of bacterial contamination

Keeping doors and windows closed, or protected by screens is a good method for keeping flies out of the home.  Good sanitation practices in and around your home will also help to keep flies out. 

Fleas are tiny insects that feed on the blood of household pets and humans.  They transmit disease and parasites with their bite.  Their bite is also painful and extremely itchy.  They often get into homes via household pets.

To learn more about fleas see the Cornell University Fact Sheet: Fleas


Dust Mites
Dust mites are very tiny and invisible to the human eye.  They live in bedding, mattresses, carpeting and upholstered furniture in our homes and eat tiny pieces of organic material, primarily pieces of shed human skin cells.  It is not the dust mites themselves that people are allergic to, but a protein in their fecal pellets.  Dust mite fecal pellets are extremely strong asthma triggers.  And constant exposure to this dust mite allergen can cause people to develop an allergy to dust mites and may even cause some people to develop asthma. 

House dust mite numbers can easily be controlled with good house cleaning practices.  To learn specific cleaning measures to control house dust mites go to the section, Cleaning Methods for Controlling Allergens in your Home.


Mice and Rats
Mice and rats, and the parasites they carry can transmit many diseases to humans.  Some of those diseases are Histoplasmosis, Hantavirus, Plague, Salmonellosis, Leptospiros, Murine Typhus, and Rat-Bite Fever.  Symptoms of some of these diseases are listed below.

This is an uncommon, but often fatal disease carried by deer mice and white footed mice.  While these are wild mice, they often invade buildings.  Mice shed the virus in urine, feces, and saliva.  People contract the virus when they inhale it it after it has found its way into the air from these animal wastes.  It is also possible to catch the virus by eating or drinking foods and liquids contaminated by virus-carrying rodents.  Most people who have caught Hantavirus have done so by cleaning, living, and working in areas infested by mice that carry the virus.  The first signs of illness are fever and muscle aches and appear one to five weeks after initial exposure. 

Rat-bite-fever is a bacterial infection that occurs when humans are bitten or scratched by mice or rats.  Symptoms include chills, fever, and vomiting.  While rat-bite-fever is a rare disease, rat bites are not.  They remain a large problem in the United States; and the highest proportion of victims are children under age 1.  Many of the bites occur while an infant is sleeping. 
Keeping your home clean and dry are good first steps to discourage rodents from entering your home

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Step 6: A Safe Home is a Healthy Home

Most Common Home Injuries
Injuries in homes are very common.  One third of all injuries that occur in the United States each year happen at home.  Home injuries cause more deaths than any other factor except car-related injuries.  The top five causes of home injury deaths for all age groups are:

The top five leading causes of fatal injuries for children under age 15 are: 

Note: Causes are listed alphabetically, and are not necessarily in order of occurrence.

Choking and Suffocation;
Choking and suffocation are the leading causes of death for children under age one. 
Choking occurs when an object a child has ingested or accidentally inhaled becomes lodged in the airway.  According to a study done by the Centers for Disease Control, 60% of all choking incidents treated in emergency rooms in 2001 were associated with a food item.

The Centers for Disease Control offers the following tips to help prevent choking:

Children under age one can be suffocated when they become entangled in drapery cords or toys with strings attached to them.  Poorly designed cribs can also create a suffocation risk as they may allow a child to get caught in such a way that breathing is restricted.  See the following Consumer Product Safety Commission (CPSC) Fact sheets for more information:


Preventing Falls in the Home
Falls are the leading cause of non-fatal home injuries for children under age 15.  But, falls are the leading cause of fatal injuries in the home for adults 70 and older. 

Some basic tips for preventing falls in your home:

For more detailed information on preventing falls on home stairs, see the Fact Sheet:   
Stair Safety: Causes and Prevention of Residential Stair Injuries

To learn more about ways to reduce home injury risks in the home for older adults, see the Fact Sheet:  Home Safety Guidelines for Older Adults

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Children four years old and younger are at the highest risk for drowning.  Most drowning of children from this age group occurs when a child is left alone in a bathtub or falls into a pool.  The tips below can prevent drowning of children:

Many homes have swimming pools in their yards.  Close supervision of children is extremely important if you or a nearby neighbor has a swimming pool.  Young children are curious and quickly drawn to water.  Therefore, children should be watched extra closely when a pool is nearby.  The Center for Disease Control notes that the key to preventing pool tragedies is to provide several layers of protection. These layers include limiting pool access, using pool alarms, closely supervising children, and being prepared in case of an emergency.

The U.S. Consumer Product Safety Commission (CPSC) offers these tips to prevent drowning:

For more information on limiting access to pools, see the U.S. Consumer Product Safety Commission publication, Safety Barrier Guidelines for Home Pools.



According to the National SAFE KIDS Campaign:

The National Center for Healthy Housing offers the following safety tips for keeping children safe from firearms in the home:


Fires and Burns
According to the U.S. Fire Administration, about 84% of all civilian deaths and 81% of civilian fire related injuries occur in residences.  According to the United States Centers for Disease Control, fires and burns are the fifth most common cause of unintentional fatal home injuries.
Most residential fire-related deaths and injuries are preventable.  To learn more about the causes of residential fires and how to protect your family in case of a fire, see the Cornell University Housing Fact Sheet, Home Fire Protection

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According to the United States Centers for Disease Control, 374 children under age 19 are treated each day in U.S. emergency rooms for poisoning.  Every day, at least two children in the U.S. die from unintentional poisoning.  Most of these cases resulted from an unsupervised child who found and consumed medication. 

Many items commonly found in homes can pose a poisoning risk to children.  Medications and common household products such as cleaners and even personal care products can be just as dangerous as chemicals marked with clear warning labels.
Follow these tips from the Centers for Disease Control to protect your children and any children that may visit your home:

Program this number into your cell phone, and place it near every phone in your home.  You can reach the poison control center any day of the year, 24 hours per day.  Call the poison control center if you think the child has ingested something that may be poison and if the child is awake and alert.  Call 911 if the child has collapsed or stopped breathing.

Other Important Safety Tips for Preventing Poisoning

For more detailed information on using and storing chemical products in your home, see the Fact Sheet, Safe Use and Storage of Hazardous Household Products


Carbon monoxide (CO) is a deadly poisonous gas that kills hundreds of people in their homes each year.  It has no odor or color.  Since CO gas cannot be seen or smelled, it makes it especially dangerous, because you may not know it is present in your home before it is too late.  Carbon monoxide gas is produced whenever a fuel is burned.  Basically, anything that burns will produce carbon monoxide gas.  To learn more about CO and how to protect you and your family from CO poisoning, go the the section on Carbon Monoxide in the module on keeping your home contaminant-free.


Lead poisoning, especially for young children, continues to be a significant problem in the United States.  When lead is absorbed into the body, it can damage the brain, kidneys, nerves and blood.  It also causes learning disabilities and behavioral problems.  If enough lead has been absorbed by the body, seizures, and even death can occur.  If your home was built before 1978, there is a good chance it contains some lead-painted surfaces.  To learn more about lead and how to prevent lead poisoning, go the section on keeping  your home contaminate free and see the information on LEAD in Section 2.

Unintentional Drug Poisoning
It is not just children who are at risk for unintentional poisoning.  According to the United States Centers for Disease Control, more than 26,000 deaths from unintentional drug poisoning occurred in the United States in 2006.  Unintentional drug poisonings for adults more than doubled in the seven year period between 1999 and 2006.  Men and middle aged people are at highest risk for unintentional drug poisonings.

For more detailed information on this issue, see the CDC publication, Unintentional Drug Poisoning in the United States


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Step 7: A Healthy Home is Well-Ventilated

What is Ventilation?
Ventilation means bringing fresh air into the house from outdoors and getting rid of stale, possibly polluted, indoor air.  During periods of the year when outdoor temperatures are moderate, providing ventilation is easy. We can simply open windows to let fresh air in and stale air out.  But during cold winter months, we heat the air in our homes to stay warm, and during hot summer months, we cool the air in our homes.  So, opening windows to provide ventilation is not a good strategy for several months of each year.  During times of excessive temperature difference between indoors and outdoors, we need to depend on mechanical ventilation as a way to get fresh air into our homes and stale air out.


Why Ventilation is Important
Pollutants in the air inside buildings, including homes, are ten to one hundred times higher than in outdoor air.  While the best method for reducing pollutant levels in your home is to control the source of the pollutant, proper ventilation is also important.  Proper ventilation can reduce concentrations of the following indoor contaminants:

To learn more about each of these contaminants click on the button


What is Mechanical Ventilation?
Mechanical ventilation involves the use of a fan to move air into or out of a building and ductwork to channel the air from the fan to the outdoors.   The duct work is attached to a vent, or openings, in the exterior wall. See Figures 1-3 below for details.

Two Primary Types of Mechanical Ventilation
The two primary types of mechanical ventilation for houses are spot ventilation and whole-house ventilation.  Bath and kitchen exhaust fans that remove moisture, odors and other pollutants at their source are examples of spot ventilation.  With spot ventilation the occupant controls when the fan comes on and how long it stays on -- either with an on-off switch or a crank timer.  Whole house ventilation means that the air in all the rooms of the house is removed and replaced with fresh air via a series of air ducts, interior room grills, and exterior vents.  A powerful fan is used to draw stale air from each room of the house and blow it out via a series of ducts and exterior vents, such as the one illustrated in Figure 3 below.  With some types of whole-house ventilation systems, a second fan draws fresh air into the house at the same time the first fan is blowing stale air out.  To learn more about whole house ventilation see the information sheet:  Residential Ventilation.


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fan duct

Figure 1:
A bathroom exhaust fanis ussually placed in the ceiling of the bathroom. A grill over the fan covers that fan but allows air to flow to the fan

Figure 2:
Ductwork, preferably rigid metal, connects the fan to a vent in the exterior wall
Figure 3:
A louvered vent provides a protected hole in the exterior wall where stale indoor air is exhausted from the house


Local Exhaust Ventilation Required in All Homes
All houses, no matter their age or how drafty, need to have local exhaust ventilation.  That means a correctly sized and installed exhaust fan in each bathroom and in the kitchen vented to the outdoors.  In addition, clothes dryers should always be vented to the outside. 

Bath and kitchen exhaust fans remove moisture, odors, and other pollutants at their source.  For example, gas cook tops and ovens emit combustion gasses, including significant amounts of carbon monoxide, directly into the kitchen.  In fact, oven exhaust gasses are basically directed right at the face of anyone standing at the stove top and cooking.  This means that an exhaust fan vented to the outdoors is critically important in kitchens with gas stoves and ovens.  Recirculation range hoods that draw air through a filter before exhausting it back to the kitchen do not meet this requirement.  The range hood must have a fan that is vented outdoors.  If your gas stove does not have a vented range hood and if you cannot have one installed, then always open a window a bit whenever preheating the oven.  When baking for several hours, open a window periodically to allow air polluted with combustion by-products to escape. 

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Important items when buying/installing a bathroom exhaust fan:

NEVER vent exhaust fans to attics, porches or crawl spaces. This is sure to cause significant mold and rot problems. The picture below illustrates what happened when a bath exhaust fan was installed and vented into an unheated porch.

The owner of this home hired an electrician to install a fan in the bathroom. The electrician, unaware of the importance of venting exhaust fans to the outdoors, vented it into the adjacent porch. After just one winter of having warm moist air blown into the porch, you can see the result.

  • Choose a fan that moves enough air.
    • Determine the volume of the bathroom and divide by 7.5
    • Example:  A bathroom is 5 feet by 7 feet with an 8-feet high ceiling for a total volume of 320 cubic feet.  Divide 320 by 7.5.  This equals 42.  Choose a fan with a CFM (cubic feet per minute) rating higher than that.
  • Choose a quiet fan.
    • A Sone is a measure of noise.  All fans have Sone ratings printed on them.  A fan rated above 3 Sones will be a very noisy fan.  A fan rated between 2 and 3 Sones will be fairly quiet.  A fan rated at 1 Sone or less will be ultra quiet.
  • Have the fan installed in such a way that its use will be encouraged.
    • Have the bath light and the fan wired together so that when the light is switched on, the fan also comes on.
    • Putting the fan on a crank timer that can be set when someone begins a shower is another method.  The fan can be set to run for 5 to ten minutes past the shower time to exhaust all moisture and then turn itself off. 
    • Installing a quiet fan will also encourage use of the fan.  No one likes a noisy fan.
  • Make CERTAIN the fan is installed correctly and vented to the outdoors.
    • Fan duct runs should be short and as straight as possible.
    • The fan duct-work should be slightly pitched to the outdoor vent.
    • Rigid metal or PVC plastic is best for fan duct work.
    • Duct work should be insulated in unheated spaces to reduce the chances of condensation.
    • Even if you hire a building tradesperson to install a new or replacement bath fan, you must be certain it has been installed correctly.


Kitchen Exhaust Fans:


Does Your Home Need Whole-House Mechanical Ventilation?
Newer homes built to be highly energy efficient and to have good ventilation rates while maintaining comfort, no matter what extremes outdoor temperatures reach, have whole-house ventilation systems.  (To learn more about whole-house ventilation systems see the Fact Sheet on Residential Ventilation).  However, some homes built since the energy crisis of the 1970s have addressed energy efficiency issues by making walls, ceilings and floors tighter to reduce air infiltration during cold winter months and hot summer months, but do not also have whole house mechanical ventilation systems.  The builders of these homes knew that building a tight house is a vital part of making certain occupants can afford to heat and cool their home.  However, if the builder was not aware that such a house also needs mechanical ventilation, or ignored that requirement, the house will likely be under-ventilated. 

Some signs your home may need whole house ventilation:

If you are concerned that your home may be under ventilated you may want to have ventilation levels in your home checked by a professional.  Certified building performance contractors have the equipment, training, and knowledge to do this.  Be certain any contractor you hire is accredited by the Building Performance Institute.  The Building Performance Institute is a national organization that develops technical standards for the performance of buildings and that trains, tests, and certifies individuals to be home performance contractors.   You can locate a list of certified building performance contractors in your area by going to the web-site:  and clicking the button on that web-page that says, Find a BPI Approved Contractor Now.

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