Answer
Apr 05, 2020 - 09:28 AM
When you're trying to keep your home a different temperature than outside (in the cold of winter or the heat of summer), there are two primary ways that heat or cold from outside gets where you don't want it: conduction (moving through solid materials, like your walls), and convection (moving along with hot or cold air). Insulation is the primary way to address conduction -- insulating materials like foam, cellulose, or fiberglass are very hard for heat to move through directly. Air sealing is the primary way to address convection. If you can stop leaks into your house, then cold air will have a harder time getting in (in winter) or out (in summer). This improves comfort, reduces drafts, and saves energy.
One way to think of air sealing and insulation is keeping warm outside on a cold windy day. Insulation without air sealing is like wearing a sweater -- it helps a bit, but the cold air can go right through. Air sealing without insulation is like wearing a windbreaker but no sweater -- it cuts the wind but you're still not warm. Put them together -- sweater and windbreaker -- and you have a comfortable combo.
Air sealing a house can make many forms, such as:
* Caulking or spray foaming around the top of your foundation or the tops of your walls in the attic;
* Choosing dense-pack cellulose or foam insulation for walls (these materials stop both convection and conduction);
* Putting new storm windows over old windows, or replacing old windows with new, better sealed windows; or
* Sealing around the edges of your attic hatch (or getting a new, airtight hatch).
To see whether your house needs air sealing, you'll need a blower door test.
One way to think of air sealing and insulation is keeping warm outside on a cold windy day. Insulation without air sealing is like wearing a sweater -- it helps a bit, but the cold air can go right through. Air sealing without insulation is like wearing a windbreaker but no sweater -- it cuts the wind but you're still not warm. Put them together -- sweater and windbreaker -- and you have a comfortable combo.
Air sealing a house can make many forms, such as:
* Caulking or spray foaming around the top of your foundation or the tops of your walls in the attic;
* Choosing dense-pack cellulose or foam insulation for walls (these materials stop both convection and conduction);
* Putting new storm windows over old windows, or replacing old windows with new, better sealed windows; or
* Sealing around the edges of your attic hatch (or getting a new, airtight hatch).
To see whether your house needs air sealing, you'll need a blower door test.
