If you own an older home and the heating, ventilation and air conditioning (HVAC) are working overtime, your energy bills seem high, and you are still uncomfortable, then a few simple repairs could make all the difference. I moved into a 1960’s-built house and lost my cool during the first summer. The air conditioner was simply unable to keep up with the heat gain each day. An energy audit may be worthwhile to pinpoint problems you can’t identify yourself, to measure the results of your improvements and to possibly qualify for a tax credit; however, my inefficiency was so severe that I decided to fix these four issues first:
Home builders didn’t begin to air seal effectively until the mid 1980’s. New windows and doors are often recommended, and they will certainly help if these are major sources of air exchange; but proper weather stripping is usually less expensive and as effective. You will greatly increase your energy efficiency by diligently weather-stripping, caulking, spray foaming, enclosing, foil taping or applying mastic to the following:
- HVAC ducts, return and supply plenums and ceiling registers
- Plumbing and electrical penetrations, outlets and switch plates
- Wall top plates
- Recessed lighting fixtures
- Kitchen and bathroom exhaust vents
- Fireplace dampers
If your attic is unconditioned, outside air needs to enter through lower soffit vents along the perimeter of the roof and superheated air needs to escape through higher gable vents, whirlybird turbine vents, pot vents, ridge vents, etc. If your attic often gets too hot, you should calculate the net free area (NFA) to determine if you have enough. Consider adding:
- Continuous soffit vents and baffles
- Roof vents or ridge vents
- Hard-wired or solar attic fans
It is easiest to fix the air leaks and attic ventilation problems before adding insulation, because chances are good that you won’t have the proper amount of ceiling insulation getting in your way. The Department of Energy estimates that 80% of homes built in the U.S. before 1980 (about 64 million homes) are insufficiently insulated. Even newer homes may lack enough. You can improve your efficiency the most by focusing your attention on the ceilings and duct work instead of the walls. I added insulation in the following order:
- Radiant barrier; cut and staple to the bottoms of the roof rafters.
- HVAC ducts;
- Fiberglass or cellulose insulation; install enough to raise the total R-value to the recommended level for your area.
The mechanical equipment used to heat and cool requires regular maintenance to operate efficiently, and a qualified technician should be called for service. Be sure to:
- Change the air filter; A dirty air filter obstructs air flow.
- Clean condenser and evaporator coil fins; Clogged fins prevent efficient heat exchange.
- Have your refrigerant levels checked and, if low, check for leaks in the condenser and evaporator coils.
- Replace your condenser, compressor and/or evaporator coil if they are older than about 15 years or are leaking. There’s no need to buy the highest efficiency units available; even the new lower efficiency units using R-410A are probably much better than the existing unit.
- Install a programmable thermostat to automatically adjust the indoor temperature during hours you are usually awake, asleep or at work.
If you are going to complete these energy efficiency improvement projects, be sure to follow all safety precautions, as working in unfinished space with tools and building materials can be hazardous. Do not work in a superheated attic, ask a friend to help blow fiberglass insulation, and hire an HVAC specialist if needed. It took many hours of work, but it is satisfying to say that it was worth the investment of time and money. By my estimate, the costs will be recovered through utility savings in less than 5 years. The increased comfort, however, is immeasurable!