Energy Efficiency 'Round the Home: Part 6 - The Garage | Direct Energy Blog

Energy Efficiency ‘Round the Home: Part 6 – In the Garage

Believe it or not, improving your home’s energy efficiency doesn’t require an advanced energy science degree. It’s really just a matter of being more aware of choices and recognizing whether they save or waste energy. Individually, some energy-wasting practices might not amount to much, but when you add them all together, you’ll gain a better picture of how how much you could save. To help you live Live Brighter, our “Energy Efficiency ‘Round the Home” series will showcase ways you can lower your home energy usage and possible reduce your monthly energy bill.

How Can I Improve the Energy Efficiency of My Garage?

Energy Efficiency 'Round the Home: Part 6 - The Garage | Direct Energy Blog
Weatherstripping this entry door can save you money on your electricity bill!

Garages pull double duty as enclosed entryways in our homes. They’re also typically used for storing vehicles, mowers, and sometimes fuels. Consequently, they’re deliberately designed to be kept separate from the conditioned living space of the rest of the house to prevent car exhaust fumes and other dangerous chemical contaminants (including your son’s garage band) from getting inside. In most homes with an attached garage, the space isn’t heated or air conditioned.

For many homeowners, the least intensive/most cost-effective way to improve their garage’s energy efficiency is to simply weatherstrip the door to their garage so that it ensures a snug weather-tight seal. Using the right weatherstripping will give you a gap-less seal to keep out the hot or cold garage temperatures and prevent those car exhausts and other contaminants from getting inside the home’s conditioned living space.

What About Insulation?

Energy Efficiency 'Round the Home: Part 6 - The Garage | Direct Energy Blog
A non-insulated garage can cost you in the long run.

If you have rooms (as part of your home’s conditioned living space) above your home’s garage, the garage ceiling should be insulated to reduce energy costs. Closed cell spray foam insulation works very well here because it also air seals. Fiberglass insulation is another good route. In this case, the insulation must be pushed up against the underside of the floor overhead and held in place using snap-in wire holders. On the other hand, if there’s no conditioned space overhead, installing ridge and soffit venting along with gable venting will improve the garage’s ventilation, reducing summertime heat build up and also control humidity.

Insulated Garage Doors — Are They Really a Thing?

Energy Efficiency 'Round the Home: Part 6 - The Garage | Direct Energy Blog
Consider what you will use your garage for before deciding if you should insulate it or not.

Yes, they are a thing…ish. First off, EnergyStar does not have an energy efficiency specification for garage doors: “Because garages are typically unconditioned space, the potential energy savings from better insulated garage doors is significantly reduced.” That said, improving your garage door’s energy efficiency doesn’t hurt your home’s over all energy efficiency. However, whether you should consider insulating your garage door or having a one installed really depends on what you use your garage for. If you use it mostly for storage and not much else, then perhaps an insulated door isn’t worth it. If you use the space as a workshop or hobby space, then having an insulated door might be worth it.

The best insulated garage doors consist of polyurethane or polystyrene insulation sandwiched between inner and outer skins, such as steel or fiberglass. They also have thermal breaks designed in so that warmth isn’t conducted through the door. For example, a garage door panel might have a big, broad aluminum band running all the way around it. This band would act as a thermal conductor. In the winter, it would be really cold and pull heat out of the garage, in the summer it would radiate heat. Using a low-thermal conducting material like vinyl in the design of that band breaks the thermal conducting.

There are many DIY solutions when it comes to insulating your garage.

In terms of DIY solutions, there are many, many kits out there. Some use spray on foam or rigid panels. Other use fiberglass insulation. My DIY preference in this case is to use rigid styrofoam panels cut to size or spray-on closed cell foam. However, if you plan to use fiberglass insulation be sure to cover it with a vinyl or plastic vapor barrier that won’t let moisture penetrate. Kraft or paper faced insulation is a vapor retarder, not a barrier. The reason is that during winter in northern states, vehicle bring in snow and ice which melts and evaporates if the garage’s temperature is at least above freezing. Without a vapor barrier in place to prevent moist air can condense on the metal or fiberglass garage door surface. Any fiberglass insulation on the door will absorb the condensation and in short order, mold will likely start growing.

If you’re thinking about buying one, take your time shopping and do a lot of comparing. Some credible experts warn that the advertised R values don’t hold up under laboratory scrutiny, especially if they don’t provide a good seal and let in drafts. With this in mind, the ball park average R-value for a residential garage door is around R8. For comparison, most home walls with 2×4 construction are insulated between R11 and R13.

Big Doors Need Careful Weatherstripping

Whether or not you have an insulated garage door, weather stripping your garage door further reduces the chance for drafts entering your home. Because most garage door systems involve the whole door assembly flexing and rolling up a track, they present a challenge when it comes to weatherstripping them. First, there’s all those gaps to seal. Vinyl door jamb stripping will do an excellent job of reducing drafts that get in around the top and sides of smooth-faced garage doors. Along the bottom of the door make sure the door’s bottom gasket is intact. If the door is wooden, make sure it’s not rotten. Also install a vinyl threshold on the floor to create a more effective seal with the door gasket. These kits are very simple to install and help keep out cold drafts and unwelcome rodents.

Exhausted by the high energy costs of your upstairs pad? In the next installment of “Energy Efficiency ‘Round the Home,” we’ll help get you in gear to rev up some savings in your garage apartment!


Vernon Trollinger is a writer with a background in home improvement, electronics, fiction writing, and archaeology. He now writes about green energy technology, home energy efficiency, the natural gas industry, and the electrical grid.

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