Every winter it happens… The wind is blowing outside; your house is warm or at least “warmish”. Outside, its COLD!
You may have noticed the drapes beginning to flutter or perhaps the draft at your feet, head, shoulders, legs. . . you get the idea. Many of those drafts come from the air leakage in your house. Air leakage is uncomfortable, costly and not particularly good for the environment. We generally find that we can lower the air leakage of an average home by between 20% and 30%. This translates into significant dollars in heating fuel saved. As you tighten your home you literally stop throwing money out the window!
It is not uncommon when we are testing homes to find that an average 2000 square foot home has something like a total of 400 Square Inches of leakage overall. That is the equivalent of having a 20” by 20” window opened all year long: Through the Summer (making you hotter) AND the winter (making you colder). If only you could just close that “window”. Unfortunately, it is not that simple but that is the basic idea around air sealing your house.
The leakage happens in a wide variety of places. Sometimes those places are very easy to spot. Hold your hand up to your bathroom fan (while it is off) on a cold day. Hold your hand up to the bottom of an exterior door. At both places you will likely feel a cool draft.
Here is another way to look at leakage in a typical house. The house below shows the common areas for leakage and air loss. Notice that cold air entering in the basement and then warm air exiting at the top of the building. This is a typical air loss profile in homes.
The Take Away:
As you can see, there is no one particular area that accounts for tremendous leakage in a house. It is generally a lot of small leaks that combine together to make a significant total air loss.
There is good news though. Some of the leaks are easier to fill than others.
Next up How to “See” Air.