Making Your Home Energy Efficient

by Susan Conbere

Two years ago, my husband and I bought a beautiful but somewhat neglected home about a block from my office. (How efficient is that?) I wouldn’t call our 1903 four square a fixer upper, but we knew we had a good amount of work to do. We wanted to restore this fine house to its glory.

But glory has to wait when you’re cold. I mean really, bone-chilling, I-am-miserable-all-the-time cold, which was our experience the winter of 2007.

Having been in the energy efficiency field for 20 years, and with gas bills at about $600 a month, I knew we had to get an energy audit. (An audit from a certified building performance tester might cost about $400.)

I knew that much of our discomfort was due to the construction of the original house. We have single-pane windows, there was no insulation in the walls, and there were cracks in the attic so big you could see to the outdoors. But to my surprise, the shoddy remodeling job in the 1998 addition was also a big contributing factor—and this is the kind of work my auditor said he sees all the time. In our case, the ductwork and air sealing was particularly bad: we were losing about 70% of our heating and cooling through gaps in the ducts. In many cases, the ducts weren’t even connected to the registers.

Working with the auditor, we came up with a plan to right the many wrongs. Here’s what any homeowner can learn from our story:

• Seal all the air gaps.

• Add insulation.

• Seal ducts.

• Put ducts in conditioned space.

• Prevent UV radiation from eating up your ducts.

• Seal recessed can lights.

• Add an air seal cover over the attic door.

• Save your receipts!

Seal all the air gaps.

Yeah, well, this was the obvious one. What wasn’t so obvious was exactly where those air gaps were. The auditor used a blower door test to help us locate a lot of air leaks we wouldn’t have found on our own. My husband then bought can after can of Great Stuff (insulating foam in a can) at Home Depot, and sealed the heck out of every nook and cranny he could find. One warning: Great Stuff disintegrates under UV light, so don’t use it outdoors.

With all this air sealing, I worried about whether the house would be too tight, but in leaky old houses like ours, that’s really unlikely. However, the auditor did the blower door test again once all the work was done to ensure that we had enough air exchange between the indoors and the outdoors for healthy indoor air. If you do a lot of air sealing, that’s a prudent step.

 
Add insulation.
Ah, insulation. It was so worth the investment—in money and labor. The walls in the older section of our home are now filled with itty bitty pieces of shredded newspaper, called cellulose, that keep us warmer in winter and cooler in summer. Over several weekends, my husband and our boys worked with the auditor to blow the insulation in through the walls and in the attic. In our case, we had to drill about 100 holes into the walls so we could blow the insulation in, and then we had to patch the holes. What a job!

There are many forms of good insulation. Explore the alternatives with your auditor. Even the pink rolls of batt insulation can do a reasonable job if installed correctly—which most isn’t. In fact, we had to reinsulate several areas in our 1998 addition because the job had been done so poorly. If you choose batts, look for those that do not contain formaldehyde.

Seal ducts.
According to ENERGY STAR, about 20 percent of the air that moves through the duct system in a typical home is lost through leaks and holes in ducts and poorly connected ducts. This leads to higher energy bills and makes it difficult to keep the house comfortable, no matter how high or low you set your thermostat. You can seal leaks in your ducts yourself using mastic sealant or metal tape and insulating all the ducts that you can get to (such as those in attics, crawlspaces, unfinished basements, and garages). Don’t use "duct tape," which doesn’t last very long. You may also want to consider aerosol duct sealing, which manufacturers claim can reduce duct leakage by up to 90%.

When possible, put ducts in conditioned space (spaces that are typically heated and cooled).

If you’re redoing your ductwork and have the option of putting it in conditioned space, do so. If the ducts leak, they’re leaking that warm or cool air to parts of the house where you can use it. Moving the ductwork out of the basement, garage, or crawl space—where you’re drawing air from—will also ensure that the air you’re breathing is a little cleaner. (Well, we hope. Be sure to vacuum regularly and use VOC-laden products sparingly.). 

Prevent UV radiation from eating up your ducts. If your ductwork is in the basement or attic, it’s exposed, and you can’t move it, be sure to install shades on any windows nearby. The UV radiation from the sun will cause the covering around the ducts to disintegrate, which will reduce the system’s efficiency. We ended up having to replace or repair most of our ductwork for this reason. It only cost about $150, but boy, was it a chore.

Seal recessed can lights. If they aren’t insulated, recessed can lights provide a nice big hole into the attic, allowing air to flow from your conditioned (heated and cooled) space to the unconditioned space where you can’t use it. This is a big energy drain. The DIY Guide to ENERGY STAR Home Sealing provides a nice description of properly sealing recessed can lights on page 2.2.

Add an air seal cover over the attic door. Here’s another low-cost way to keep air from your attic in your attic. You can buy a prefabricated door, or build one yourself. Look to page 2.1 of the DIY Guide to ENERGY STAR Home Sealing for ideas. ToolBase provides another good guide, along with CAD drawings. 

After their energy audit, the author and her husband founded Energy Penguin, an energy auditing and weatherization firm in Silver Spring. Learn more at www.energypenguin.com.