Cutting Your Heating Costs This Winter, Part 2: How To Air Seal

Hopefully you found "Heating Your New England Home on a Budget, Part 1: Air Sealing" useful as an overall description of how air leaks from your house. Remember, in addition to cutting your heating costs, air sealing will also save you money in the summer by keeping cool air in your home.

Okay now that you have a good idea of the problem let’s talk about how to fix it.

The idea is simple: block all the holes where the air is escaping. The challenge is that your house is a large and complex structure with many different levels, walls, opening, etc. Finding all the air leaks is not going to be easy.

But let’s start with the major culprits and the easiest to fix. It makes sense to start with the ones that will give you the biggest bang for your buck. These are typically found in the attic or basement.

A quick note, it’s important to wear the proper safety equipment. You’ll be dealing with insulation and spray foam as well as crawling around in dusty areas. At a minimum you’ll want eye protection, a properly rated dust mask, and gloves. Wearing a hat as well as a set of coveralls is also a good idea.

Let’s start with the attic. If you go up into your attic or crawl space and pull back the insulation, you can see where the ceiling below has been opened up when your house was built or remodeled. Many of the standard penetrations include:

• Recessed lights



• Light boxes



• HVAC duct work
  

Also, around attic edges is the “top plate” of outside walls. This is where the top of wall framing meets ceiling framing. Through the top plate you’ll see holes where electrical wiring and plumbing piping is coming into the attic. You’ll want to close these holes by spraying canned foam insulation (available at any local hardware store). This can take some time to work all the way around the attic. Once you’ve done that, locate where any interior walls come against the ceiling framing and fill in those holes too.

Look around any chimneys or flue pipes that come into the attic. When you seal around these items use only non-flammable materials. You don’t want to solve one problem (air leakage) only to create another (potential fire damage).

Lastly, be careful around recessed lights. They generate lots of heat and can’t be sealed using the standard approaches. Typically you can either replace the lights with air sealed units or build a box around them with foam board to prevent air escaping. If you do build a box, be sure that it’s large enough to allow all heat produced by the light to dissipate.

By the time you've finished this project you’re dirty and sore. It probably took longer than you anticipated. However, the best news is that you just saved yourself money in heating and cooling bills while helping to save the planet.