If your home is built using typical construction methods and is more than 20 years old, you can be pretty certain it is not as energy efficient as it should be.

You cannot expect to make an older existing home as efficient as a brand new home, but investing in some energy improvements would be wise and probably provide a reasonable economic payback.

There are several methods to determine how efficient your home is. First, talk with several of your neighbors and compare your utility bills with theirs on a month-by-month basis. Their bills will depend upon their specific family size, living habits and house size, but if you check with enough of them, they should average out.

Another method is to do a simple rule-of-thumb calculation to estimate how energy efficient your home is. If your home is inefficient during the heating season, it is generally just as inefficient when cooling during the summer. This calculation determines how many Btu (British thermal units) of energy your house uses for an entire year, per-square-foot of floor area, adjusted for your climate.

Then total all the energy you have used for an entire year. Use your gas and electric utility bills, oil or propane deliveries, firewood, etc. Use the following factors to convert to Btu equivalents: 1 kilowatt-hour of electricity equals 3,414 Btu, 1 cubic foot of natural gas equals 1,025 Btu, 1 gallon of propane equals 91,000 Btu, 1 gallon of oil equals 138,700 Btu, and 1 cord of wood equals 19 million Btu.

Now, divide the total annual Btu used by the square footage of the living area of your house. In order to adjust this for your climate, divide this result by the sum of the heat and cooling degree days for your area. Degree days are the number of degrees the outdoor temperature is above or below 65 degrees. At an outdoor temperature of 65 degrees, it is assumed you don’t have to heat or cool your home. Your local weather service can give you monthly figures, which you can total for the year.

If the final calculated result is 10 or less, you can consider your house to be reasonably efficient. If it is between 10 and 20, there is room for improvement. If it is greater than 20, your house needs major improvements. Keep in mind, this is just an estimate for a typical family of four.

It also helps to know where your home is losing heat so that you know where to look for possible efficiency improvements. Each house is unique, but in general, ceilings account for 15 percent of losses (gains during summer); windows/doors, 26 percent; walls, 13 percent; basement/slab, 11 percent; and air infiltration (leakage), 35 percent.

Tightening up your home, meaning reducing air infiltration, is a good place to start. Check the weather stripping on the doors by closing each door on a dollar bill. You should feel some resistance when you try to pull it out. Try this in several locations on each door because resistance will vary.

Check the air tightness of your window weather stripping. Wait for a windy day and hold a lighted stick of incense near the weather stripping. Watching the smoke trail will indicate any leaks. Do the same around any ceiling penetrations by ceiling fans or exhaust fans, recessed lights, etc. If you have a basement, check for gaps where the walls rest on the foundation and fill any with spray foam insulation.

Make sure your attic insulation thickness is up to current recommended levels for your area. Wear a breathing mask and gloves when handling insulation in the attic. If it is blown-in insulation, use a rake to level it out before measuring its depth. Air movement through the attic can create deep and shallow spots. Make sure the attic insulation is not blocking soffit air inlet vents.

Check to see if your home has wall insulation and note the type of insulation. Switch off the circuit breakers to wall outlets on outside walls. Double check with a circuit tester to be sure the power is off. Remove the electrical faceplate. Using a nonconducting plastic knife, poke around the sides of conduit box to look for signs of insulation. Having a professional infrared scan of your house will also indicate if you have adequate wall insulation.

Since heating and cooling equipment accounts for the majority of your utility bills, have them serviced regularly to be sure they are operating at their maximum efficiency. If they are old, have your contractor do a payback analysis for installing new, higher-efficiency models. This will save energy and generally improve your comfort level.

Send inquiries to James Dulley, Country Lines, 6906 Royalgreen Dr., Cincinnati, OH 45244, or visit here.