Our Home Energy Audit
Submitted by admin_green on Fri, 09/11/2009 - 12:00
It all comes down to air and water and where they do and don't go.
There used to be something known as "Chinese restaurant syndrome." The idea was that you enjoyed eating the food, but you really didn't want to look in the kitchen to see how it was cooked. We suppose in these days of Bizarre Foods and such that this may no longer be the case, but you get the idea.
Tom Krawczyk demonstrates why energy audits will never make the list of the world's most glamorous jobs. This is inside a cement crawlspace under the house. It was pretty cold, as well as filthy.
It's the same with energy efficiency. You really enjoy having it, but you've got to go crawling into some pretty uncomfortable and uninviting parts of your house to check it out. Luckily for us, Tom Krawczyk did it for us on April 30, 2008 (you can e-mail Tom here). Our Web guy tagged along and filmed it, and we'll be adding some videos from it to the site soon. Dirty Jobs indeed!
As Tom explained it, conserving heat in a house comes down to two simple things: controlling the movement of air and controlling the movement of water (the Department of Energy gives a good breakdown of an energy audit here.). Each has certain patterns of movement that they naturally follow, and these are not always in the best interest of efficient heating and cooling. And getting both to behave properly makes things very interesting.
Basically, you want hot (or cold) air to stay in, and water to get out and stay out.
The white snake is actually the duct venting the upstairs bathroom. It's too long, which decreases efficiency and may allow water to pool.
Much of what Tom found is easy to fix and will bring immediate results: ducts with gaps in the insulation, and wall spaces where insulation is missing. This is low-hanging fruit in terms of value for the expense of improvement.
Tom began by doing a visual inspection, and checking the flow from all bathroom and kitchen fans. He went up into the attic and checked the insulation and ducting. We use cellulose insulation...which is mostly newspaper shredded to the consistency of fine powder snow...so a hazmat suit was required. He found a lot to fix up here, but the fixes will mostly be easy to do.
Warm air naturally moves upward, and air migrates from hotter places to colder places. The smallest gap gives it room to do this. So an attic with a thick blanket of high-quality insulation can be undone by things as simple as gaps in corners, insulation cut off an inch too short and joins that aren't caulked. Tom found quite a few of these. They allow hot air to move out of the living area and into the attic, where it isn't useful.
These are easy fixes, though, and return any cost quickly in energy savings.
These gaps have another potential problem: hotter air is usually wetter air, and can bring water into places like attics and wall spaces, where it can promote the growth of mold. So fix the gaps!
Bathroom fans are particularly important for removing water from the wettest room in the house, the bathroom. Our fan isn't as strong as it needs to be (one bathroom also lacks a fan), and as the picture above shows, the duct from it curves unnecessarily. This can be fixed by simply trimming the pipe. Most ductwork is very inexpensive, so this work should be done. Make sure all joins are well sealed.
This space around the ducting in the basement is like a superhighway for cold, damp air from the basement to move through the house.
From the broiling attic to the damp, moist basement and crawlspaces under the house. Different environment, same problems, same simple fixes. There were multiple spots where ducts weren't sealed off, allowing cold, moist basement air to move freely behind walls and into various rooms. A great way to passively air condition a house, and a great way to encourage mold. Tom also inspected closely around the rim of the house, where the structure meets the ground. There were holes to be plugged (helps keep out the critters, as well!), and cracks to be caulked.
Thermal imaging or a ceiling-mounted recessed light fixture. The magenta circle is cold air pouring through the area around the fixture. Time for some caulking here.
Next came the fun part. Tom closed all the doors and windows, and depressurized the house using a giant fan sealed into the front door. This turned every air leak in the house into a mighty wind. Using an infrared thermal scope, Tom could visually pinpoint every place where cold air was freely moving into the house. By and large, windows came through with high marks, but recessed light fixtures, wall sockets, wall and floor vents, and a few corners and wall joins showed their true colors. These places will need to be sealed, and we will have to look at some of the cool spots behind walls (most likely due to gaps in the insulation) when we rebuild the house as the B&B's manse. It DOES explain why the home study always seemed colder than the rest of the house. It was.
Our report card.
Tom gave us a full report of his audit on June 2, 2008. Our house earned a HERS (Home Energy Rating System) Index of 93. HERS is a standard of energy use that measures the relative efficiency of the home (it was established by RESNET. Their site is here, but it's not great. There's a good blog post on HERS here.) That's better than most American homes, but if we want Energy Star rating, we're going to have to get below 85.
Energy efficiency is becoming an increasingly important issue beyond the home: banks are starting to consider it when assigning mortgages, and potential buyers are becoming savvy about it.
On a simpler economic level, energy efficiency pays for itself faster than any other investment you can make in your home. Tom's recommendations for the house will allow us to achieve a HERS rating of 68. If we follow all of Tom's recommendations, we will recoup the investment in under 10 years, and will receive more than double the value in savings over the next 20. That's an easy choice to make.
You can find Tom's audit report here.
You can find Tom's breakdown of cost and benefit, plus the HERS rating before and after, here.
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