The ABCs of Saving Energy
Across the country this month, some homeowners are writing checks for yet another high cooling bill, while others are dreading the rising heating costs as winter approaches. Although the quick fix to save on energy costs is to turn up the thermostat in the summer and turn it down in the winter, making simple, cost-effective changes in the hidden areas of your home — the attic, basement and crawlspace — can help you save money without sacrificing comfort.
“It’s not like windows or new siding, which have curb appeal,” says Doug Anderson, project manager of the EPA’s Energy Star program. “But these hidden areas are also very important. Some of [the improvements you can make] are relatively cost-effective, and you can even do them yourself. Getting your home to be more energy efficient is a great way of doing something green that pays you back.” So with that in mind, let’s take it from the top.
A is for Attic
We know that warm air rises. In the winter, the heated air in your home is pulled up to the attic, creating negative pressure called the stack effect. That pressure pulls in outside air through any leaks around doors and windows and into the home’s main living areas. That’s why your home feels even colder on a cold day.
To fight the stack effect and keep warm air in, seal your attic first. “Make sure you air-seal before you insulate — you don’t want to go back later and dig through insulation to seal leaks,” Anderson says. You can also plug all those leaks around windows and doors.
For smaller cracks less than one-half inch, use a long-lasting, flexible elastomeric caulk made of silicon, latex and/or acrylic. Silicon caulks are better but emit stronger odors, Anderson says. Elastomeric caulk is available in a clear version, so you won’t have to match paint colors.
For gaps up to three inches long, use canned spray foam, either urethane or latex, which hardens after you spray it. Common brands include Great Stuff from Dow, Handi-Foam from Fomo Products, Hilti foam from Hilti Corp. and DAP foam from DAP Products, according to Anderson.
Now you’re ready to insulate. A number of insulation choices are available, but keep in mind that the higher the R-value, the better the insulating properties.
• Fiberglass batting is the granddaddy of insulation and is still the most common type used today. It’s rated about R-3.6 per inch.
• Blown fiberglass has an R-value of about 2.4 per inch, and fits more uniformly around wires and pipes.
• Blown cellulose is made from recycled newspapers and is rated about R-3.6 per inch. Unlike fiberglass, which performs less well in hot and cold weather, cellulose works even better in extreme heat and cold, says Steve Tetreault of ThermalTec, an insulation company based in Toano, Va. Blown cellulose is roughly equal in cost to fiberglass batting and costs 10 percent more than blown fiberglass in new construction, but costs 10 percent less than blown fiberglass when retrofitting an existing home. An added bonus: Blown cellulose contains boric acid, which makes it insect-resistant. The downside: If cellulose gets wet, it’s ruined.
• Closed-cell urethane foam is the most expensive type of insulation, and can cost three times more than blown cellulose, says Art Mowry, owner of Atlantic Spray Systems in Lightfoot, Va. However, it is rated up to R-6 per inch. It’s also extremely long lasting. While cellulose insulation will lose its effectiveness after 20 to 30 years, closed cell foam is a once-and-done solution.
To get the best of both worlds, some homeowners, including Anderson, start with a two-inch coating of urethane foam on the attic ceiling and then fill the rest with less-expensive blown cellulose. You should also weatherstrip and insulate your attic hatch or door to keep heated or cooled air in your living area.
In hot climates, consider adding a radiant barrier to the inside of the attic roof. A radiant barrier, which looks like a big sheet of aluminum foil, can reduce the attic temperature by 20 to 30 degrees. “Attics in the South tend to be 140 degrees in the summertime,” says Anderson. Radiant barriers can help lower summer cooling costs.
B is for Basement
If your basement isn’t insulated, start your efforts there. “In the North, a big source of energy loss is through uninsulated basement walls,” Anderson says. “Insulating those basement walls can really improve the overall energy efficiency of the home. But the trick is when you’re dealing with a basement, you’re also dealing with moisture.”
New research by Building Science Corporation, a Boston-based architecture and building science consulting firm, indicates that yesterday’s technique of stapling a moisture barrier to the basement wall, especially at the bottom of the wall, and then covering it with interior insulation can cause mold, decay and odor problems. “Blocking moisture out does not necessarily work,” Anderson says. “Water can get trapped behind the moisture barrier. When the ground is wet, moisture can get sucked up into the footers. You want to let the wall dry to the outside.”
Based on the latest research, the recommendation now for both new homes and renovations is to install a rigid, semipermeable foam insulation, available from such companies as Dow Chemical and Owens Corning, with a perm rating of 1 or better, Anderson says. That allows the moisture to get through. Run a dehumidifier to remove moisture from the air.
Outside the home, make sure water drains away from the foundation and that moisture doesn’t drip from plants and run down the walls. On the upper part of the exterior wall, Anderson recommends Tuff-R, an impermeable rigid foam insulation product made by Dow.
C is for Crawlspace
Sealing, insulating and conditioning (heating and cooling) your home’s crawlspace, if done properly, are great ways to control moisture and save on energy costs. “If you have ducts down there [in the crawlspace], you can save as much as 10 percent of your total annual energy bill” by insulating and conditioning the space, Anderson says.
In a conditioned crawlspace, exterior foundation walls are insulated, and conditioned air from the home is introduced into the space. “You’re basically keeping a small basement cooled and heated inside your house,” explains Paul Supplee, owner of National Property Inspections in Williamsburg, Va. If a poly-vapor barrier is used, Supplee recommends going beyond the code-required 6 to 10 inches to ensure efficiency. It’s critical to make sure the vapor barrier is thick enough and properly sealed. “The thicker, the better,” says Anderson.
Hiring an experienced contractor to do the work is important — this is not a do-it-yourself project. If the ground vapor barrier and the crawlspace aren’t properly sealed, “all of a sudden you have excess moisture and it has no place to go,” says Supplee.
When sealed and insulated properly, a conditioned crawlspace can not only reduce your energy costs, but can also help prevent the problems associated with a damp crawlspace, including problems with insects, buckled hardwood floors in the living area and other moisture damage and musty odors.
D is for Ducts
Whether they run through your attic, basement or crawlspace, ducts can be huge energy wasters. “In the average home, 20 percent of the air leaks out of the ducts before it gets to your registers,” Anderson says. “If that air is leaking and it’s running through an unconditioned space — an attic or crawlspace or even a basement — you could be losing a lot of energy.”
Just as with unconditioned spaces, you need to seal and insulate your ductwork. If you can see the duct seams where the metal comes together, seal them with a shiny foil tape with a UL-181 label or with duct mastic, also called duct sealant. (Tip: Duct tape doesn’t work on ducts.) Next, bury the ducts in cellulose or fiberglass insulation. “That can really improve the performance of the ducts,” Anderson notes.
Ductwork typically runs through the attics of homes in the South and the basements of homes in the North. If those spaces are conditioned, or at the very least sealed and insulated, you won’t lose as much energy from the ducts, and can save on energy costs. It’s another benefit of following the ABCs, and improving the efficiency of your attic, basement or crawlspace.
Freelance writer Karen Haywood Queen covers such topics as home design, landscaping, technology and building. She’s based in Williamsburg, Va.
Home Energy Audits
Home Performance with Energy Star, a national whole-house energy audit program from the EPA and theDepartment of Energy, is designed to help homeowners improve residential energy efficiency. “Normally, if you call an HVAC guy, you’ll get an HVAC answer,” says Doug Anderson of Energy Star. “If you call an insulation guy, you’ll get an insulation answer. If you call a windows guy, you’ll get a windows answer.” With this program, however, contractors take building-science classes and are certified to look at all aspects of sealing and weatherizing a home.
The program is currently available in the states of Arizona, California, Colorado, Florida, Georgia, Idaho, Illinois, Massachusetts, Maryland, Maine, Minnesota, Missouri, New Jersey, New York, Ohio, Oregon, Pennsylvania, Rhode Island, Texas, Vermont, Wisconsin and Wyoming. A typical home energy audit costs $250 to $600.