30 Sep Is your House Making your Family Ill? Check Your Indoor Air Quality
It’s a fact: indoor air quality can affect our health. Many respiratory problems and headaches can be traced to a sick house. In temperate climates, where windows and doors are left open constantly, this isn’t a serious concern.
But in cold climates like Canada’s, where we have become experts at sealing our houses airtight to save on heating costs, maintaining air quality with good ventilation is important. To understand why that is, it’s instructive to understand how home construction practices have evolved over time. Forty years ago, heating oil cost 18 cents a gallon, houses had R7 (about 2.5 inches) insulation in the attic, and nobody worried too much about few drafts from around the windows or out of the electrical outlets. Over the years as oil prices went up, we took measures to make our houses virtually airtight to keep hot air from escaping, thus reducing our heating costs. So we diligently went about adding more insulation, installing better windows and doors, and improving the vapour barrier.
Downside to keeping warm air from escaping
While these measures proved effective at eliminating those cold drafts, they came with a cost to our indoor air quality, since they also eliminated our sources of fresh air. Meanwhile, humidity from normal living activities suddenly became trapped inside, leading to condensation on widow interiors and thus providing ideal conditions for mould and dust mites to propagate; a sick house. Modern furnishings only compounded the problem, since chemicals used in their manufacture can accumulate in the air by “out gassing” from such products as particle board, foam in furniture, glues in carpets and household cleaners. By the late 80’s the problem was recognized and the heat recovery air exchanger was developed to provide a supply of fresh air controlled by the humidity level in the house. Today, building codes require that an air exchanger (not necessarily with heat recovery) be installed in all new electrically heated houses.
What to do to maintain healthy indoor air quality
Of course, there are several ways to maintain good air quality in your house – and possibly improve your family’s health at the same time. I recently attended an Indoor Air Quality conference presented by the Canada Mortgage and Housing Corporation (CMHC) and learned some surprising facts. For instance:
- Carpets can harbour dust and dust mites. In order to clean a carpet properly each square metre must be vacuumed for 15 minutes. Yes, 15 minutes! (Who does that?)
- If you have a pillow more than a few years old, 50% of its weight can be dust mite feces. Dust mite proof pillow cases are available. Replace your pillows regularly.
- If the humidity level in your house is typically above 55%, this can easily occur in some cooler areas of the basement, for example, then mould growth is likely.
- Electronic air filters if not properly maintained can produce ozone, a respiratory irritant. Replace with a good quality HEPA filter.
- When you vacuum you think you are sucking up the dust, right. Wrong. The very small particles such as pollens go straight though and out the other end. Installing a HEPA filter will help but the best option is a central vacuum that is vented outside.
- Avoid storing boxes or hanging clothes against outside walls, particularly in unfinished basements. In older houses the closets are always on the inside walls, but in some newer designs I have noticed closets against the outside wall. This is not a good idea as any storage or clothes will act as insulation, producing a cooler and therefore high humidity zone between the storage and the wall. Perfect conditions for mould growth.
- Many of the products we buy, from furnishings to cleaning materials, emit toxic gasses into the air. These amounts may be small, even barely noticeable, but nevertheless they are there.
Maybe opening a window once in a while, even in winter, is not such a bad idea.