Carolyn Tagliarino, a single woman living in a handsome little home in hot, humid Magnolia, Texas, is nearing retirement. She’s worried that her utility bills will surpass her fixed income—unless she takes action now. Carolyn’s daughter, Joanna Martini, and her family are moving back to Texas from California and staying with Carolyn while they househunt. Staying upstairs, Joanna has noticed hot indoor temperatures, even when the air conditioner is on high. The electric bill for this 1,700-squarefoot home averages $200 to $500 a month—about twice what it should be—which prompted Joanna to call Natural Home for help.
Carolyn has about $10,000 to spend on energy-efficiency upgrades. Her home was built by a previous owner, and it appears they were not aware of the old adage “Design it right, build it tight and ventilate it right.” I offered Carolyn several suggestions for improving her home’s performance, but implementing all of them would exceed her total project budget, so I listed them by priority. If Carolyn is able to implement all of the suggestions over time, she should at least halve her utility bills and see a significant reduction in her homeowner’s insurance premiums. The home will be less drafty and significantly more comfortable, too.
Carolyn’s top priorities
Discovering and fixing the home’s most urgent efficiency issues will immediately reduce energy bills.
1. FIND THE LEAKS.
When I visited on an August afternoon, the house felt very humid and airflow was noticeably limited. The air conditioner was clearly having a hard time fighting the 100-degree heat. A quick walk-through revealed a high amount of outside air infiltration and leaking attic air-conditioning ducts.
Solution: I encouraged Carolyn to hire a home-performance contractor to perform a “blower door test” and to inspect the ducts. She followed through by ordering a thermal-imaging test for about $150. It showed excessive leaks in multiple locations, including under and around a second-floor bathtub. Several of the problems have easy fixes, such as installing new weather-stripping on all exterior doors, especially between the kitchen and garage. The test also suggested that installing insulation gaskets behind all electrical outlets and switch plates would help. These easy fixes cost less than $100 and require simple parts found at most home-improvement centers. See Carolyn’s complete thermal imaging report below.
Cost: To complete all of the items recommended in the thermal-imaging report, Carolyn will need to spend between $1,500 and $3,500.
2. IMPROVE AIR FLOW.
Air registers throughout the house are missing internal dampers, making it impossible to direct air flow properly. In the breakfast room, for example, the air supply register directs air straight toward the return air grille, eliminating any chance for the cool, conditioned air to mix with the room air.
Solution: Carolyn needs new registers that direct air flow to exterior walls. Installers must carefully caulk the gap between the register boots and the gypsum board ceiling.
Cost: $500 to $750
3. REPLACE INEFFICIENT HEATING AND COOLING EQUIPMENT.
The inefficient central air conditioner and furnace are installed in the hot attic above the main floor. They appear to be original to the house, which was built in the mid-1990s.
Solution: Carolyn should replace her old air conditioner and furnace with new equipment with these features: a SEER (Seasonal Energy Efficiency Rating) of 14 or better; a 95 percent efficient “sealed-combustion” gas furnace; a variable-speed air-handler with an ECM motor; and a humidity-sensing, digital, programmable thermostat. This equipment provides the right mix of energy savings and humidity reduction. A sealed-combustion furnace will allow Carolyn to seal the attic from outside air in the future, when she can afford a metal roof. Read more about this on page 38.
Cost: $3,500 to $5,500
A thermal-imaging home inspection
Home inspectors Your Home Check conducted Carolyn’s thermal-imaging home inspection using a special infrared camera that reveals leaks and gaps in a home’s thermal envelope. The inspectors discovered deficiencies that were quite useful in determining which problems to remedy first. Here are the results:
1. Air loss at attic A/C plenum—probably because of leaks in ducting
2. Air infiltration at main room baseboard
3. Air infiltration at upstairs return air chase, significantly reducing effectiveness of AC system
4. Moisture at base of upstairs bathtub
5. Air infiltration at downstairs return air chase wall, significantly reducing effectiveness of AC system
6. Heat infiltration at fireplace wall, which is on an exterior wall and apparently not sealed to prevent outside air infiltration
7. No insulation in sunroom ceiling
8. No insulation in upstairs bedroom ceiling for at least two entire bays in framing system
9. Heat gain at main room wall next to fireplace near outlet and baseboard
10. Heat gain at wall next to bathtub
11. Air loss at A/C vent in living room ceiling
12. Air loss at A/C vent in sunroom ceiling
13. Excessive thermal loss at main room windows facing east (heat gain 98+ degrees)
14. Infrared scanning did not reveal any leaks in drains; however, rust was noted in the A/C drain pan, which should remain dry. Refrigerant line should be insulated to prevent condensation from dripping into pan.
15. Moisture at master bath wall next to garage because of condensationforming at a PVC air-conditioning drain pipe
While many items on this list can be rectified with a few tubes of caulk and some pipe insulation, others require more complex remedies and/or a professional. Insulation throughout the entire attic should be supplemented with at least six additional inches of blown-in cellulose. Leaks in the air-conditioning plenums need to be fixed, as well.
Finding local experts:
Reputable local contractors are generally listed in the Yellow Pages under “Energy Conserving Products and Services.” Insist that heating and air-conditioning contractors perform a careful system-sizing analysis to determine the proper size for equipment.
Carolyn’s green wish list
Carolyn should save for these future projects, which will help reduce her energy bills by half.
4. STOP WATER HEATER BACKDRAFTING.
The standard, 40-gallon gas water heater takes up a precious corner of the laundry room, which is right off the breakfast room. Joanna reports a faint smell of natural gas and/or the products of combustion. My suspicion is that the dryer, when operating, creates a strong enough vacuum to cause “backdrafting” of the flue gases from the water heater. Flue gases usually include a mix of chemicals, including carbon monoxide, hydrocarbons and sulphur dioxide, and inhaling them is not healthy.
Solution: Carolyn should replace the water heater with a tankless type mounted on the exterior wall directly outside the laundry room. This would eliminate the problems associated with a combustion-burning appliance operating within the home’s conditioned space, and it will save a bit on gas consumption, too. Placing the new water heater near the existing unit’s water and gas piping will minimize installation costs.
Cost: $2,000 to $2,500
5. REPLACE THE ROOF.
The existing, dark shingle roof absorbs a lot of heat, further increasing the air conditioner’s work load. It should be replaced within the next five years.
Solution: Given her relatively modest budget and the importance of dealing with more pressing problems first, I suggest Carolyn wait to replace her roof until she can afford an unpainted, Galvalume metal panel roof. Carolyn should install the metal roof above the existing roof, creating an air space in between. This air space allows the underside of the metal roofing panels to act as a radiant barrier, greatly reducing solar heat gain in the attic. My favorite metal roof products are the 26-gauge, concealed-fastener, snap-together type with a Class 4 hail-resistance rating such as the ProSnap 100 by Central Texas Metal Roofing Supply. Installed properly, the new roof should save at least $1,500 a year in reduced air-conditioning costs and homeowner’s insurance premiums, more than offsetting the cost. With a selfventilating roof in place, Carolyn will no longer need to ventilate her attic. Sealedattic homes have far fewer air-infiltration problems and are considerably less humid and more comfortable than others.
Cost: $6,500 to $10,000
6. REDUCE HEAT GAIN THROUGH WINDOWS.
All of the home’s original windows are aluminum-framed and single-pane. Thermal imaging confirmed the windows are admitting a lot of outside air. The best solution would be to replace them with new fiberglass-framed units with Southern low-emissivity double-pane glazing. However, the anticipated $5,000 to $10,000 price tag for new windows is beyond Carolyn’s project budget for now. The upstairs bedroom on the home’s west side has a large window that’s bombarded by the hot afternoon sun. This window alone could account for as much as a quarter-ton of unnecessary air-conditioning load and makes for a hot, uncomfortable bedroom for Carolyn’s young granddaughter.
Solution: Though she can’t afford new windows right now, Carolyn placed full-size solar screens on her windows to reduce solar heat gain. Installing these shades is an inexpensive and effective temporary solution that will help reduce heat gain until Carolyn can afford to install new windows.
Cost: $50 per window for solar screens;
$5,000 to $10,000 for new windows
RX at your house
In my experience evaluating homes in Southern climates over the past 25 years, the most common problems are associated with outside air infiltration and unwanted solar heat gain. My suggestions to combat these problems:
1. Purchase a “blower-door” test to find leak points and seal them up. Don’t overlook simple and obvious solutions such as closing the fireplace flue, repairing nonfunctioning kitchen and bath exhaust fans, and replacing worn outdoor weather-stripping.
2. Have your air-conditioning duct system tested for leaks using a “duct-blaster” test, then patch leaks. Even as little as a 15 to 20 percent duct-leakage rate can diminish overall air-conditioning system efficiency by 50 percent.
3. Shade windows, particularly those on homes’ south and west sides, with awnings or solar screens. When replacing the roof, choose as lightly colored shingles as possible, preferably white. A white or unpainted Galvalume sheet-metal roof, installed with an air space beneath it, is the best choice for energy savings.
Peter Pfeiffer is a founding principal at green-building firm Barley & Pfeiffer Architects in Austin, Texas. Pfeiffer was named Fellow of the American Institute of Architects in 2004 and has contributed to several national magazines and television shows.
Your Home Check
American Standard Heating and Air Conditioning
Control Comfort thermostats
Central Texas Metal Roofing
Pro Snap 100 metal roofs
Integrity fiberglass windows
North Solar Screen
PVC-free solar shades
tankless water heaters
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