Creating Energy Efficient and Sustainable Homes Starts with Unglamorous but Easy Basics
By Larry Harmon
Have you ever wondered why some new homes use so little energy compared to existing homes? You may think it is because of new codes or improved materials or equipment. If this is true, then why do some new homes use more energy than others? And why do some existing homes perform better—are more comfortable and use less energy—than many new homes?
With energy costs high, many homeowners are looking to improve their existing homes. Does this describe you or your clients? Many believe that new windows; higher-efficiency equipment; or technologies, like solar, wind or geothermal, are the answer. Certainly these can make a difference. What you may not know is that much of the secret to high-performing homes—old or new—lies out of sight. A key to efficient modern construction is more care given to air barrier and insulation systems, including how they are installed and how they can affect the home—positively or negatively.
To get the most out of any of sustainable technologies, you must first make the shell as efficient as possible. Without an efficient building shell, you need higher capacity (more expensive) equipment.
To get started, you or your clients need to think about a home in a systematic manner. Calculate what conservation measures save in energy and dollars. The high-tech, really cool stuff, such as high-efficiency HVAC, solar or geothermal heat, and visible things, like high-performance windows, are usually not needed first. For the best results existing homes really need simple and unglamorous basics.
Think of a home like a child in winter. You wouldn’t buy your child high-tech skis before providing them with a coat and hat. Consider the following:
The child needs a good hat: Fix the attic.
This is a two-stage approach. First, air seal holes to stop conditioned air moving into the attic. Sounds simple, but the key is knowing what to look for and where. There are thousands of cold bonus rooms above garages because this basic wasn’t done. After air sealing, insulate the attic to an R-value that at least meets (hopefully exceeds) code. Insulating without air sealing first causes moisture problems. The now cooler attic condenses moisture from the warm, humid house air.
The child needs a warm coat: Insulate the walls.
The child needs snow pants and boots: Fix the basement or crawlspace.
Retrofitting walls and basements of homes is unglamorous. Again, air sealing is a basic, but often overlooked, first step. The type of insulation and how it’s installed have major impacts on performance.
Windows do impact efficiency, but the cost of one 15-square-foot replacement window can oftentimes insulate 600 to 700 square feet of wall. Get the biggest bang for your buck: Insulate your walls first.
The child needs a scarf, so cold air doesn’t bypass the warm clothing: Air seal the home.
Covering these basics can result in huge leaps in comfort, energy savings and decreased environmental impacts. When the project is complete, you won’t see anything new, but you will feel it as you sit in your home or enjoy your new lower utility bills. It’s not glamorous, but it works. And it helps the other, really cool technologies work better, too.
Larry Harmon is vice president of Air Barrier Solutions LLC and the former executive director of the Building Performance Institute, Malta, N.Y.