It helps to narrow down the possible spaces where a home could lose energy. It normally occurs in one of these five places:
- Floors and below grade spaces
- Doors and windows
- Air leakage (infiltration)
Now remember these areas are not all the same in terms of energy leakage. Heat loss due to infiltration is far more significant than what is lost through walls and ceilings. In order to understand their relative importance, it helps to look at energy loss in this order:
- Infiltration / Air Leakage: 35%
- Windows and Doors: 18%-20%
- Floors and Below Grade Space: 15%-18%
- Walls: 12%-14%
- Ceilings: 10%
One might guess that the best way to prepare for winter is by purchasing insulation. While certainly not a bad idea, it's not always the best investment. Reducing air leaks around certain openings is a more direct way to stem the flow of energy loss.
Where are air leaks occurring in your home?
Believe it or not, the biggest culprits for air leakage/infiltration may be places you never thought about before. Air can leak out through plumbing vents, switches, electrical outlets, recessed lighting fixtures exposed to the attic; vertical plumbing stacks open to the basement, attic stairs, or any other opening that is exposed to the coolest parts of the home. Through these openings, heated air can be drawn out of the home and escapes through the roof.
What is the bottom line for fixing infiltration leakage?
Focus on insulating the largest openings first. This may require purchasing new windows or doors with better insulation. While certainly more costly than weather-stripping or insulation, they will provide the most bang for the buck in terms of energy efficiency. After windows and doors have been addressed, consider insulating your attic. Although more heat is lost through the walls than the attic, it is a lot less expensive.
Is it time for a Home Energy Audit?
If you need to determine where heat is escaping in your home, it helps to start with a comprehensive checklist. This gives you a basis with which to evaluate your home and prioritize energy-efficient upgrades.
According to the "Do It Yourself Home Energy Audits" page on the Department of Energy's website (Energy.gov), there are several areas of your home that will need inspection.
The basement: If your basement is unheated, it is probably insulated with an R-value of 25, which is the minimum recommended level of insulation. It may be worth upgrading this to a higher level of insulation, such as R-19. Make sure your water heater, furnace ducts, and hot water pipes are also insulated.
Heating and cooling equipment: If you have a forced-air furnace, make sure the filters are changed regularly, generally about once every month or two, or more frequently during periods of high energy usage. Hire a professional to check and clean your equipment at least once per year.
Air leaks: As mentioned earlier, plumbing and electrical openings are a major source of air leakage. In addition to electrical outlets, pipes and plumbing fixtures look for cracks in the mortar, foundation and siding of your home as well as near windows and doors. These can usually be sealed with caulk or weather-stripping.
Check insulation in walls and ceilings: Depending on the year when your home was built, the insulation levels could be less than the recommended minimum. Given the rising cost of energy, this level of insulation might not be enough. Determine whether openings for ductwork, pipes and chimneys are sealed properly and if not, apply an expanding foam caulk or other sealant.
Checking the insulation in a wall is much more difficult than in the attic. Turn off the electricity at the circuit breaker level and remove wall outlets, then gently probe the wall with a long stick. Insulation in the wall will create a slight resistance. You could also make a small hole in a closet wall or some other unobtrusive spot. Ideally, the cavity should be filled with insulation material.
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