Ever notice how people that work outside tend to be healthier than those that work inside, even when it’s cold outside? It may have something to do with all the fresh air they get. Conversely, people that are closed indoors without access to fresh air tend to get sick more often. This may have to do with the fact that living in modern homes is akin to living in a plastic bag.
In order to increase the energy efficiency of homes, in modern construction in addition to adding insulation around the home, we also enclose the home in a plastic vapour barrier and seal up any penetrations as best we can. Just like a really thick wool sweater, it doesn’t really help if the wind cuts right through. We need an air barrier as well as insulation to keep the heat in.
Living in a plastic bag can trap “bad air” in and keep “fresh air” out. That is why is important to air out the home from time to time. We often do this without thinking about it. When we use our kitchen and bathroom fans, for example, we are forcing air out, which in turn sucks fresh air in through all the imperfections in the air barrier. Every time we go outside and open our front door, we let fresh air in. In some homes that may be enough, but if you stay at home during the day, or have people who are sick staying home, you might want to air out the home a little more often.
Personally, I like opening up all the windows for a short period of time and getting an air current to cycle the air. That way you let in a bunch of cold air but the house (floors, walls and furniture) doesn’t have a chance to cool down. Other people like opening up a window a little bit for a longer period of time. Others add mechanical devices such as a Heat Recovery Ventilator (HRV) to their home which automatically brings in air from the outside while trying to recover the heat.
Try to make it a point to air out the house as much as possible on those days that the outside temperature is mild. Don’t forget to use the kitchen and bathroom fans and for goodness sake, open a window; it’s cold outside.