Is your home getting enough ventilation?

One of the problems that we see in many homes in Revelstoke is inadequate ventilation. There should be enough ventilation in a home so that the air can be completely replaced with fresh air every three hours.

  • Apr. 26, 2011 6:00 a.m.

Thermalstat! By Chantal Keerak

One of the problems that we see in many homes in Revelstoke is inadequate ventilation. There should be enough ventilation in a home so that the air can be completely replaced with fresh air every three hours.

Blower door tests have been done on several hundred homes in Revelstoke and we have found that most homes built after 1980 – and many of the homes built before this time – do not get enough ventilation through natural means. If there is mold or excessive condensation on the window, it is often not a problem with the window. Instead, it can be a sign of not enough ventilation.

Inadequate ventilation can lead to poor indoor air quality and moisture problems in the home.  We spend 90 per cent of our time indoors and the majority of that time is in our homes.

The air quality in our homes is often overlooked and it can make you sick. Asthma, allergies, suppressed immune systems, forgetfulness, behavior problems, headaches, cancer and auto-immune diseases are just a few of the illnesses that have been linked to the quality of air in our homes.

You can add ventilation the old fashioned way and open a window.  However, this often ineffective, cold, and uncomfortable.

The most common way to add mechanical ventilation is to run the bathroom exhaust fan. You may be thinking, “I’m not running that thing it sounds like a freight train.”

Yes, many of them do, however, for about $100 you can get one that will move a lot more air with a lot less noise. Look for one that is Energy Star rated, has a very low sone rating and is meant for continuous ventilation.

Bathroom exhaust fans are inexpensive and often better than nothing but they do have some pitfalls. When the exhaust fan runs it pulls air in through leaks in the home to replace the air that is being exhausted.

It is difficult to control where the “fresh” air is coming from and it may be coming through areas that are less than ideal such as musty basements or moldy attics.

It is also possible to draw in soil gases such as radon, which is the second leading cause of lung cancer.

To find out if radon is a problem in your home you can get a $30 test kit from the BC Lung Association.

Exhaust devices such as exhaust fans can sometimes create a large enough vacuum in your home to cause combustion spillage. This is when the chimney gases from your furnace, hot water heater, fireplace, wood or pellet stove are drawn back into the home, which can be deadly.

If you have any combustion appliances in your home, make sure you have a working carbon monoxide tester. We often see the potential for combustion spillage in homes where powerful kitchen exhaust fans have been installed. A depressurization test will help determine if this is a concern for your home.

The best way to add ventilation in a home is a balanced heat recovery ventilator (HRV). An HRV continually supplies fresh air to the home from ducting connected directly to the outdoors. The outdoor air comes into the HRV and is preheated by the air that is being exhausted, recovering about 65 per cent of the heat or more.

As long as the system is properly balanced, the potential for combustion spillage and radon contamination is greatly reduced.  If a home has a furnace in it, an HRV can usually be added quite easily. An HRV is something that every new home should have and will likely be required in the building code for new homes in the future.  LiveSmart BC has grants for HRV’s and bathroom exhaust fans. Visit for more information.

Another key to good indoor air quality is to take a close look at the things you allow in your home. No, I am not talking about your smelly pooch. There are many potentially hazardous chemicals used in our homes and many are odorless.

Some of the most common are volatile organic compounds (VOC’s) including formaldehyde, benzene, and trichloroethylene. They are found in everything from building materials, fabrics and cleaners to the personal care products we use every day and the stuffed animals our children play with.

These chemicals and many others that are commonly used in household products release gas and can build up in the air creating adverse short- and long-term health effects.

Becoming more aware of what the products you bring into your home are made of, limiting the ones with potentially harmful ingredients and ensuring your home has adequate ventilation will go a long way to improve the air quality in your home. That way you, your family and even your pooch can all breathe a bit easier.

Chantal Keerak is a professional mechanical engineer. Her Revelstoke based company, VerdaTech Energy Management and Consulting BC, provides heating and ventilation system design and energy efficiency assessments for residential and commercial buildings throughout BC. She can be reached at 250 814-8719.