The House Itself


Air Conditioning

When selecting an air conditioner, look at the Energy Efficiency Rating (EER). For a room air conditioner, an EER of 8 is good, 10 or more is excellent. Central air conditioners are rated by a Seasonal Energy Efficiency Rating (SEER). For central air conditioners, an SEER of 10 or more is good, 12 or more is excellent. The SEER may not be shown on the unit, but the number is usually available if you ask the dealer. For heat pumps, look for a high Coefficient of Performance (COP). The COP is the ratio between heat delivered and energy consumed, and will vary with outdoor temperature. COP ratings are provided for outdoor temperatures of 17 degrees F and 47 degrees F; the higher the COP, the more efficient the heat pump is, and the less it will cost to operate. A good heat pump will have COP's of 2.0 or greater at 17 degrees F and 3.0 or greater at 47 degrees F.

The best place to locate an air conditioner is on the north side of the house, out of the sun. The sun's heat makes the unit work harder. If your unit must be located in the sun, building a wooden shelter around it to block the sun will help it run more efficiently.

Central air conditioning and heat pump systems should be inspected, cleaned and tuned every 3 years by a professional serviceperson. Besides extending the life of the system, regular servicing can lead to 10-20% energy savings.

Use your air conditioner only when you really need to. On cool and breezy days and nights, you can keep your house cool by opening windows and turning on fans. Consider installing a ceiling fan. If you buy a fan with a reversible motor, you can save on heating as well by circulating the hot air that rises to the ceiling (it can be as much as 15 degrees warmer than the air at floor level).


Find out if your home is sufficiently insulated. The "R" value of your insulation represents the insulation's resistance to heat flow. A higher R value means greater insulation. Common R values range from 11 to 38. R values are additive; for example, 2 layers of R19 insulation is equivalent to one layer of R38 insulation. One thing to remember: if the insulation is compressed to a less than normal thickness, the R value is decreased.


Prevent heat loss through windows and doors by:

When installing new windows, keep in mind that double pane windows retain twice as much heat as single-pane windows. Double-pane windows with a low emissivity (low-E) coating often cost no more than units with regular glass and can double the R-value of the window. A low-E coating is an extremely thin metallic layer that lets the sun's warming rays in, but doesn't let them back out. Also, don't overlook the importance of frames, good wooden frames will prevent a lot of the leakage that would occur with aluminum frames.


Make sure the damper on your fireplace is closed when not in use. Otherwise, 5% of your heating expense could be going up the chimney.


By switching to energy-efficient lighting, you reduce the burning of fossil fuels that creates pollution. For every 10,000 kilowatt hours of electricity saved:

Pollution Prevented
Fuel Not BurnedCarbon DioxideSulfur Dioxide Nitrogen Oxides
18 Barrels of Crude Oil10 tons CO254 kg SO219 kg NOx
4.7 tons of Coal12 tons CO2100 kg SO240 kg NOx
Average All Fuels7.5 tons CO258 kg SO225 kg NOx
Source: US EPA

Based on the average CO2 emissions from all fuels, saving 10,000 Kwh of electricity is also equivalent to planting 2.9 acres of trees or taking 1.4 cars off the road per year.

As your incandescent bulbs burn out, try replacing them with compact fluorescent bulbs. These bulbs screw into regular light bulb sockets and emit a light that looks similar to that from an incandescent. They cost a lot more than incandescent bulbs (generally, $5 to $25 a piece), but the energy they save over the course of their lifetimes will make up for the difference at least 2 or 3 times over. They use only about 1/4 of the energy that incandescent require and can last ten times as long. Amazingly, simply replacing one traditional bulb with a compact fluorescent will reduce the amount of carbon dioxide emitted into the atmosphere by half a ton over the life of the bulb. Do some research before you buy compact fluorescent bulbs. They are not suitable for all uses (e.g. they should not be used with dimmer switches) and will not fit all fixtures.

If you use incandescent bulbs, use them wisely. Smaller wattage bulbs aren't as efficient as higher wattage bulbs. In a fixture with several sockets, you'll save by using one high-wattage bulb instead of 2 or 3 smaller bulbs. For example, it takes two 60-watt bulbs, or four 40-watt bulbs to light a space to the same brightness as one 100-watt bulb. Using the 100-watt bulb will cost 17% less than using the 60-watt bulbs and 38% less than using the 40-watt bulbs.

"Energy Miser" or "Supersaver" type incandescent bulbs use 5-13% less electricity than ordinary bulbs. They cost a little more, but save money over their lifetime. "Long-life" incandescent bulbs are LESS efficient than standard bulbs; use them only where replacing bulbs is very difficult, such as in stairways and attics.

Dimmer controls reduce the power consumed by incandescent bulbs. The dimmer the light, the less electricity consumed. Dimmers are not effective in reducing the electricity used by fluorescent bulbs.

Use task lighting as much as possible, lighting only the part of the room you are using (such as a desk or reading chair). Turn off lights when not in use.

When repainting the interior of your home, remember that light-colored walls will make the house appear brighter with less lighting than dark walls.

Water Heater

When you install your water heater, heat traps (or one-way valves) installed on both the hot and cold water lines will prevent excessive heat loss through water pipes. Without heat traps, hot water rises and cool water falls within the pipes, allowing heat from the water to be lost to the surroundings. Heat traps typically cost $30 and save $15-30 per year. Some new water heaters have built in heat traps.

Set your water temperature at the lowest setting which will provide you with sufficient hot water. For most households, setting the temperature about midway between the "low" and "medium" settings, at 110-120 degrees, will work. If you have a dishwasher without a booster heater, you'll probably need to set your water at 140 degrees, the "medium" setting.

Generally, for each 10 degrees reduction in water heater setting, you will reduce your water heating bills 3-5%. When you go on vacation, reduce the water heater to the lowest possible setting or, if practical, turn it off.

Put your hand on the side of the water heater. If it feels warm, it is not sufficiently insulated. Wrap an insulating blanket around it; you will recover the cost of the blanket within a few months. Insulating blankets are available at hardware stores. This is especially important if the water heater is in an unheated area.

To help your water heater operate more efficiently, every couple of months, drain about 2 quarts from the valve faucet at the bottom of the water heater. This will prevent the accumulation of sediment.

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