Category: Air Quality
When you think of age-old rivalries or battles your mind might go to sports teams or one state versus another but it probably doesn’t go to tight home versus proper ventilation one. That’s understandable, but in the building world it is one that is gaining traction. Lets first look at each side of the battle and get a working knowledge of them.
A tight home refers to how well the exterior envelope of the home is resistant to air penetration. The tighter the home, the less air it lets in or out. Most people refer to air penetration as “drafts”. In some homes you can feel the cold air in the wintertime seeping into the home. That would not be a tight house. Building technology has come a long way and with the advent of spray foam, house wraps and so forth homes are a lot tighter than they used to be. The reason a tight house is beneficial is that it will hold the warm air inside during the winter and the cool air inside during the summer. This has a direct impact by reducing the heating and cooling costs. Seems like a simple solution and we can end the article here. Well there are some downsides to a tight home. We’ll get to them a little later.
Proper ventilation contributes to the overall indoor air quality of your home. In simple terms it is taking the bad air and contaminates out of the home and replacing it with fresh and/or filtered air. This is accomplished using items like exhaust fans, kitchen range hoods and a fresh air supply unit. So what’s the problem and how is this a battle with a tight home?
The battle comes in that homes are being built to do everything they can to not allow air to enter or leave the home. Exhaust fans and fresh air intake are meant to do exactly that. On the tight home side of things, the argument is that you are taking conditioned air and exhausting it out. The same with bringing air into the home, causing extra stress on the HVAC system. This is a valid point, however we need to examine it a bit closer.
Studies have found that the air inside a home can be up to 5 times more polluted than outside air. How does it get so polluted? Our normal living produces a lot of contaminants. Just think of your typical day. You wake up and take a shower. The shower produces moisture that if left unresolved can turn into mildew or mold. Then you go to the kitchen for breakfast and your morning coffee. Guess what cooking and making coffee does – yep, produces contaminates. Oh and by the way, unless you are holding your breath during all this, breathing produces CO2 that can build up in your home. We are barely alive and haven’t even gotten out of our pajamas (might be a slight exaggeration). Add in pets, cleaners, candles and a hundred more things and you can see how the air can become so polluted.
So we don’t want to exhaust conditioned air out or bring unconditioned air in, but we also need to get all the bad things out of the house. So what do we do? Here is where we try to make sense of everything. The energy efficiency side is always going to argue for less and the indoor air quality side is always going to argue for more. What we need to strive for is a balance. For most homes, as little as 30 to 50 CFM of exhaust during normal activity is all that is needed. When a shower or the cooktop is in use – a bit more is needed. The key to all of this is that when you utilize mechanical solutions (exhaust fans and air intake units) you are in control. You determine how much, when and where the air comes in or leaves. So instead of annoying drafts, you can direct the air how you want it.
Another way to counteract the energy usage is to utilize energy efficient exhaust fans and air intake units. There are a plenty of models currently on the market that will meet the air movement needed and fit within the budget.
Hopefully this gives you a better understanding of the balance between good indoor air quality and energy efficiency. So the next time you are tempted to not utilize your exhaust fans because you’re worried about “wasting” energy, remember that your indoor air quality is also very important.
For more information about indoor air quality please read through the many blog post Air King has created over the years. For more information about exhaust fans, range hoods or fresh air intake, utilize the menu links at the top of this page.