Do you know how to ventilate your home? How often do you open a window or sense the need for fresh air? According to researchers, very few people are aware of the need for ventilation, and many have zero perception of the relationship between indoor air quality and health.
Since the energy crisis in the 1970s our buildings are increasingly airtight, reducing access to fresh air. This has taken a toll on our health, according to Dr. Tim Sharpe of the Glasgow School of Art.
Poor indoor air quality, particularly in bedrooms, is hard for people to detect. There are clear links between poor ventilation and ill-health, so people need to be aware of the buildup of CO2 and other pollutants in their homes and their potential impact on health.
Sharpe and a team of researchers surveyed 200 homeowners and found the following:
- 83% of Mechanical Extract Systems were underperforming, with 42% below Building Regulations requirements for moisture control
- 63% of trickle vents were kept closed
- Only 20% of people leave bedroom windows open at night
- 82% of people had received no advice on ventilation
- There was no perception of Indoor Air Quality (IAQ)
Because of Sharpe’s research, all new buildings in Scotland must now be equipped with CO2 sensors to give residents an indication of how well their homes are being ventilated.
I purchased a CO2 monitor this summer (found here) and watched the levels vary dramatically depending on ventilation. Summer is the time of year when our house is closed up much of the time. Thus our levels, measured in parts per million, were higher than desired. (Optimal levels range from 350 ppm to 1,000 ppm.)
Our levels varied from 1,100 to the mid-300s depending on time of day and access to fresh air. Most of the time they hovered in the 800 range. The CO2 equaled outside air after a monsoon, as seen below.
It’s important to note that while CO2 levels do not give you specifics regarding toxic mold or other contaminants, high CO2 levels do keep bad company and can indicate an unhealthy indoor environment.
How to Ventilate Your Home
- Be more aware of the need for fresh air.
- Take note of the presence of chemicals in the home. Chemicals such as formaldehyde used in building materials will off-gas and impact IAQ. Choose chemical-free household products when possible.
- Watch moisture. Be aware of water leaks. Ideal humidity levels range from 40-50%. (For more on mold growth, see A Beginner’s Guide to Toxic Mold.)
- Keep trickle vents (common in Europe) or windows open when cooking or showering.
- Open windows at night.
- Dry laundry near an open window. (See Dr. Sharpe’s previous study Environmental Assessment of Domestic Laundering.)
- Make sure you understand how the ventilation system of your property works. Clean vents regularly. Here’s a before and after of one of our larger vents.
Dr. Tim Sharpe discusses his research and offers more practical information in this edition of The Connecting Place.
Ventilation is equally important in office settings and schools. Check out these previous posts for more specifics.