Saturday, November 14, 2009
Posted by Kate at 11:33 AM
We had contractors in the house in late October to work on air sealing our 130-year-old home. (For those of you in Europe, any home this old is considered venerable in the US.) We'd had our home evaluated for energy efficiency earlier this year, so this was the follow-on work to improve our "envelope" as they say in the business. We were pleasantly surprised to find that as old as our home is, the efficiency was no worse than the average new construction home. Still, there was room for improvement.
That's a picture of a blower door up above. We latched the other exterior doors and sealed all the windows in our home. Then this was installed in our front door and the fan shown there was turned on. It's a powerful fan, and it depressurized our entire house. Then the workers went around checking for any points of air infiltration from outside, and did their best to seal them up. (I'd done some work on this myself since the initial energy audit.)
Of course, these improvements cost money, and not a trivial amount. For what we spent on energy efficiency improvements, we could have made a couple mortgage payments. We see this as a necessary precondition for installing any form of sustainable energy heating system though. Where we live, we heat our home fairly steadily from mid-November to mid-March, with an extra two months of at least occasional heating. If we're to spend money on passive solar heating, or even if we stay with oil heating as long as that's feasible, it only makes sense to make our home as efficient as possible. It's simply the right thing to do, and we can afford it at the moment.
I know a lot of people out there can't even contemplate spending a few thousand dollars on energy efficiency, no matter how much sense it makes. I've posted recently on cheap insulating strategies, and I urge you to check them out if you haven't already. There are tips there for both renters and homeowners. But I picked up a couple extra tips on air sealing from the contractors that I want to share.
Install safety guards in all electrical outlets on exterior walls. You know those little plastic plugs that prevent toddlers from sticking their fingers in sockets and electrocuting themselves? Put them to good use even after your kids or grandkids are grown. Electrical outlets are very often heat leaks because they reside in gaps in the insulation of your walls. The plastic guards can significantly reduce the infiltration of cold air through these gaps.
Look to the cobwebs. Maybe you're such a tidy housekeeper that there are no cobwebs in your home. We've got 'em in spades. Spiders spin their webs where there is airflow. So when you see cobwebs near windows or doors, it's a good indication that there's an air gap somewhere very close by. Cracks in plaster walls are another major culprit.
Check the trim work around all windows and doors. Very small gaps between the wall and the trim allow for an amazing amount of heat transfer. This can be true even if you have modern double- or triple-paned windows. Silicone caulking is your friend. Use it to seal those gaps, even if they look too small to be significant. Believe me, they are significant. Silicone caulking is cheap and simple enough to use that anyone can learn to do it. Get a good scraping tool for the excess caulk to make it look neat and tidy. After a little practice you'll do very nearly as well as the professionals.
With a blower door installed, every air gap in the house becomes evident. If paying a professional to install insulation or air seal your house is out of the question, you might want to schedule an energy audit that includes a blower door anyway. Many utility companies apparently offer free energy audits to their customers, or some portion of their customer base that qualifies based on income. Ours does not. Even if you have to pay for an audit, it will likely cost a small fraction of what the air sealing and insulation work would, perhaps a few hundred dollars.
The blower door will show you exactly where the air gaps are in your house. Some of them you may not be able to address with silicone caulking and a little ingenuity. It may take professional expertise and/or tools. But if you're better set up than we were to mark the air gaps that are evident when the blower door is in place and operating, you could then go about remedying many of them yourself after the audit is finished. I recommend you use brightly colored sticky notes to mark the location of air leaks. Trying to write down all the locations of leaks while the blower door was in place didn't work for us. There were too many to list, and we sometimes weren't sure afterwards what was meant by our own notes. If you take the time before the energy audit happens to work on sealing the obvious visible gaps, you'll be ahead of the game, with fewer air leaks to record during the brief time the blower door is running.
Adding insulation to an attic is also work that can be done by non-professionals. If you've got a weekend and the motivation to do so, this is a job you can do for yourself. Check out a book from the library for some basic tips if you feel you need them.
If your furnace resides in an otherwise unheated, unfinished basement, you might want to put some insulation on the walls around the furnace. Unfinished basements are very common in our part of the country, and furnaces tend to be situated out of the way and right up against a wall. The basement walls in our house are stone in the oldest part of the house, and that stone obviously conducts heat away from the furnace and into the earth. Stopping that constant draining of heat away from the furnace makes a big difference in how often it must fire up and consume fuel.
The good news after all of the expense and work we put into these efficiency improvements is that our home is noticeably warmer and the temperature steadier. We can tell that the house is losing less heat overnight, and it warms up faster when we put the heat on in the morning. It's nice to have such a noticeable and pleasing improvement for the money spent. We now feel ready to seriously consider alternative heating for our old home. More on that to come soonish.