For most of us, improving energy conservation isn’t about big, expensive projects such as installing a more efficient furnace or high-performance windows. Instead, it involves investing relatively small amounts of time and money to fix a slew of little problems that secretly rob our family’s comfort and cash and contribute to global warming. In fact, we can make meaningful strides on a single weekend with as little as a few hundred dollars. A home-energy audit is an excellent place to start. Most utilities companies offer this service for $100 to $150. A technician uses a large door-mounted fan to alter the air pressure in your home and then photographs the air leaks with an infrared camera. In addition, he or she completes an inventory of other things that waste electricity and heating fuel.
Professional audits are ideal because they rate your home’s performance in quantitative terms, but you can conduct your own visual inspection and figure out much of what’s needed. My wife and I did just that last fall and enjoyed a much cozier (and energy-conserving) winter.
We broke the project into three days of work spread over two weekends. First we conducted a thorough inspection to identify insulation and air-infiltration problems and estimate materials. We tallied 1,400 sq. ft. of attic, 72 outlets and receptacles, 50 roof-truss bays, 28 HVAC registers, 220 ft. of ducts and 140 ft. of rim joist. Next, we purchased all of the materials we needed at the nearest home center. Finally, we divided the tasks between us and tackled the work, one level at a time. Here’s how you can, too.
Attic
Start by measuring the thickness and type of insulation in your attic. If you need more, add loose fire-retardantcellulose insulation. It doesn’t matter what type of insulation you have; cellulose will provide the highest performance at the lowest cost, and it’s the easiest to install.
Before you begin, locate and seal any holes where cables or plumbing pipes exit walls from below. This helps to prevent moisture from rising into the space and hampering the insulation’s performance.
Blowing attic insulation is a two-person job that is best completed before summer, when the attic will be uncomfortably hot. The equipment is available for rent or loan at most home centers. One person dumps the material into the blower hopper on the ground while the other person directs the business end of the hose in the attic. Tip: Turn the blower off after every couple of bags to check with each other by cell phone. The blower will be too loud and the distance too great for normal voice communication.
Moving through a truss-framed attic requires care because you must step on truss cords that are hidden below the existing insulation to avoid puncturing the drywall ceiling below. You also have to be careful not to block the intake airflow from soffit vents as you add insulation. The best safeguard is to staple Windblocks (see drawing, opposite) and baffles at the eaves to ensure maximum insulation and airflow. This also prevents cold air from the soffit vents from sneaking under the insulation. Windblocks and baffles must be in place before you add insulation.
To meet the recommended R-49 value in our home, we added 8 in. of GreenFiber Cocoon Blow-In Attic Insulation. It took one morning’s work to blow 40 bags (900 pounds) of insulation. The total cost was about $277.
Be sure to insulate and seal small voids. It won’t do much good to double your attic insulation if the access hatch or pull-down stairway isn’t well-insulated and sealed. To match the R-value of the rest of the attic, glue multiple layers of rigid foam insulation to the top of the hatch so you are sure it will stay in place when you position the panel. (With a loose piece of batt insulation, you never know.) Also install weatherstripping along the opening where the panel rests to prevent moist air from escaping into the attic.
Older recessed ceiling lights and exhaust fans are notorious for leaking conditioned air and moisture into the attic. In fact, an energy audit at a friend’s home concluded that the dozens of recessed ceiling lights from a 10-year-old remodeling project had created the home‘s greatest energy leaks. In the past, insulation had to be held back from the fixtures to avoid heat buildup that could cause fires, but modern fixtures usually are sealed and rated for insulation contact (IC).
To fix leaks, you can make foil-faced boxes out of rigid foam insulation to fit over the old fixtures and caulk them in place in the attic, though it may be better to replace the fixtures with sealed units (as little as $13 each) and bury them in insulation. Either way, caulk around the opening where the fixture penetrates the ceiling below to block air movement.
Living space
Drafty doors and windows are obvious problems that are easily corrected with new weatherstripping, sweeps and caulk. But often it’s the more subtle leaks that are the biggest energy robbers.
For example, if your home has forced-air heat or central air conditioning, it is not uncommon to have significant gaps between the duct and the floor or wall surface. In that case, air from outside the duct can mix with the conditioned air as it enters the room, and the conditioned air can flow into floor and wall cavities, where it can travel to the attic.
To fix this problem, remove the register grilles and seal the ducts to the surface with foil tape. Don’t overlook toe-kick registers under cabinets. We had noticed that our kitchen cabinets were warm in winter but were shocked to discover a 2-in. gap between the edge of the duct and the toe kick, which allowed much of the forced air to blow under the cabinets rather than through the grille.
Other leaks can occur around electric receptacles and switches — the average home has lots of them, so leaks can really add up. We installed foam gaskets behind each of the 72 faceplates in our home. We also caulked any gaps we discovered between the boxes and the walls. Don’t limit this to exterior walls; boxes on interior walls are just as likely to leak conditioned air and spread moisture.
Unfinished basements
What’s out of sight must be on your mind if you are serious about improving your home’s energy performance. Start with the furnace and water heater; then move on to the heating ducts, hot-water pipes, rim joists and any openings where pipes or cables rise through the floor above.
Furnace and water heater — Change your furnace filter monthly so it doesn’t impede airflow. This goes for both heating and air conditioning seasons. Consider lowering the temperature on your water heater to 120 degrees, and wrap the outside of the tank in an insulation blanket if it is warm to the touch. Flushing sediment from the bottom of the tank once a year also will improve its efficiency.
Heating ducts — Examine ducts for gaps. Ducts are typically made of sections of sheet metal secured with screws. The joints seldom are airtight, which means conditioned air can escape from supply lines, and external air can be sucked into return lines.
Air-duct sealant or mastic is the best material to seal these joints. When applied properly, it will not degrade over time or lose its grip as heat and cold causes the duct to expand and contract. Brush the prescribed 1/16-in.-thick coating of mastic on all exposed HVAC duct joints, and pay special attention to the right-angle transition boots that terminate at the registers. These bent-metal components often harbor the biggest gaps.
If you prefer to use tape rather than sealant, choose foil tape, never ordinary duct tape — studies say it will fail over time. We were able to seal all of the ducts in our basement with a half-gallon tub of Master Flow Water-Based Air Duct Sealant from The Home Depot.
Once the sealant cures, wrap the ducts with insulation so the conditioned air inside stays warm (or cool) until it reaches the living space. Depending on your access and budget, you may prefer foil-face fiberglass or reflective bubble-wrap duct insulation.
Hot-water pipes — Insulating water pipes reduces heat loss and can raise water temperature 2 to 4 degrees Fahrenheit. This will allow you to lower your water heater’s temperature without feeling a difference at the faucet. Closed-cell-foam pipe insulation is sized so the inside diameter of the insulation matches the exterior diameter of the pipe. Slip the correct size of insulation over the pipes. Cut right angles 45 degrees so they fit together, and tape all of the joints with house-wrap tape.
Rim joists — Insulating and sealing the rim joist along the top of the foundation is critical to conserving energy and improving comfort because it prevents cold and moisture from migrating into the walls above. That’s especially important where duct registers and plumbing supply lines are located.
Other simple measures
Once you address your home’s hidden energy burglars, don’t neglect the obvious projects you may have put off in the past. Install a programmable thermostat that will automatically lower the heat or air conditioning while you are at work or asleep. Replace incandescent light bulbs with compact fluorescent lamps (CFLs). (Special models are available for decorative and dimmable fixtures.) Even small savings add up in the long term, and in the meantime, you’ll enjoy a more comfortable home.
Club member Tim Sullivan stays warm in his draft-free, well-insulated Minnesota home.