Reducing Your House's Operating Costs

Many cost effective ways to lower energy costs are very simple, inexpensive and can be done in a couple of minutes. Here are just a few:

Use windows for ventilation. Most houses have been designed to take advantage of natural cooling breezes when they are available. When the outside air temperature is comfortable, turn off the furnace and air conditioner (using the switch on the thermostat) and open windows on opposite sides of the house to allow cross-ventilation. Make sure interior doors are also open. Wide eaves will even allow you to leave windows open when rain threatens, as long as it's not driven by a strong wind. During parts of the summer, it's better not to open the windows, even when it cools off at night, because of the high humidity in most parts of the state. In general, when it's humid and you need to run the air conditioner all day, you should probably use the air conditioner at night as well.

Window treatments capture
heat in winter and reflect
heat in the summer.
Use window treatments to control solar heating.
Some houses can maximize the opportunity to capture free heat from the sun. During winter, windows that are in direct sunlight should have their coverings (drapes, blinds or curtains) open and other windows should be covered unless you're admiring the view or need the natural light. During the summer, reverse this pattern and close the coverings on windows that are in direct sunlight. East and west windows are often the most significant source of unwanted summer heat, north and south windows may be less important since they may be shaded by overhangs. During spring and fall, modify these rules of thumb as necessary to keep the house comfortable.

Allow free circulation of heating and cooling air. Don't place furniture or other objects where they can block the air flow from registers. As much as practical, you should keep interior doors open, at least a couple of inches, to allow air to return to the central return register. If you hold an interior door open a 1/4" or so and feel a strong flow of air through the crack when the furnace fan is on, then closing the door will cause an imbalance in air distribution. If that door must normally be closed, the bottom should be trimmed to allow return air to flow under the door.

Set moderate indoor temperatures. Dress for the season: cooler in summer and warmer in winter. Old federal guidelines recommended 68 for winter thermostat settings, but that's uncomfortable for many people. Try setting the thermostat at 70 in the winter and 77 in the summer. You can adjust up or down from these settings to keep comfortable, but remember every degree you increase the temperature setting in winter will add about three percent to your heating bill. And every degree cooler you set the thermostat in summer will increase your cooling bill about four percent.

Programmable thermostats
make energy saving easy.

Reset the thermostat when nobody's home.
If everybody leaves the house for work or school, set the thermostat back to 60-65 in winter or up to 80 or higher in summer. Return the thermostat to its proper setting when you return home. Most furnaces and air conditioners are strong enough to make the house comfortable in a few minutes. (There is no truth to the claim that "it takes more energy to warm the house back up than you saved by setting back the thermostat"). Even if you have small children at home and can't set back the thermostat back daily, remember this if you leave town for the weekend.

Use the thermostat correctly. Set it at the temperature you want and let it do its job. If the house is uncomfortable, adjust the thermostat setting a degree or two. Don't turn it way up or way down - it won't warm or cool the house any faster, and setting the thermostat beyond the desired temperature will overheat or overcool the house. Then you'll be tempted to open windows to cool off or warm up areas.

Change the furnace filter regularly. The normally-recommended interval is once per month, but in tight construction such as this it's probably okay to go a couple of months per filter. Replaceable filters cost less than a dollar and are usually available at the grocery store as well as hardware stores. Changing the filter before it gets filthy will reduce the work the furnace fan has to do and improve air circulation in the house. And don't run the furnace without a filter in place because this will reduce the efficiency of the furnace heat exchanger and the air conditioning coil.

Use bathroom fans to remove moisture. This is particularly important in summer when the extra humidity adds to your air conditioning costs. During spring and fall, it may just make the house less comfortable. In winter, if the air is very dry, you can leave the fan off and open the bathroom door after a shower to disperse humidity into the house. However, any significant condensation on windows or walls indicates that humidity is too high. Always remember to turn off the fan after the humid air has been exhausted.

Minimize humidity from cooking. In houses without range hoods or exhaust fans, it's important to use lids on pans, especially when simmering or boiling items for a long time. Because most newly-constructed houses are designed to have minimal air leakage, the air inside will tend to be more humid than normal. Watch out for condensation on windows and walls - that's a sign that humidity is too high for your health and the health of the house.

Insulate exposed hot water pipes. If this was not done during construction, do it now. This simple, do-it-yourself project will take less than an hour and use less than $20 worth of the split black foam pipe insulation usually available in hardware stores. Insulate all the accessible hot water pipes and the first 24" of cold water pipe where it connects to the water heater.

Reduce hot water temperature. After insulating the pipes, you should be able to reduce the thermostat setting on your water heater. Many gas water heater thermostats are not marked in degrees but as settings from "warm" to "hot." Turn the dial to the next lower temperature and see if you run out of hot water. Continue reducing the temperature every few days until you find the lowest setting that will provide sufficient hot water on a normal day. You may need to increase the temperature occasionally when you expect overnight guests, and then return it to the lower temperature after the company leaves.

Turn off unneeded lights. It does not use more electricity to switch on a light than to leave it on. Whenever you're leaving a room empty, you should switch off the light, especially if it is a standard, incandescent light.

Install high-efficiency lights. Standard, incandescent light bulbs are very inefficient because most of the energy they consume is emitted as heat, not light. They're cheap, but have a rated life of only 750-1000 hours. Screw-in compact fluorescent lights, available in hardware stores, may cost $10-15, but last for 10,000 hours and produce the same amount of light for only about 1/4th as much electricity. They are a wise investment for lights that are used a lot, such as hallways, kitchens and other lights that are normally used three or more hours a day.

These and other tips can be found in the booklet, Tips for Energy Savers, that is available from the Energy Office or at

Another source for asking energy saving questions is "Ask an Energy Expert" at the Energy Efficiency and Renewable Energy Network. To contact the Energy Expert, call 1-800-363-3732, fax 1-703-893-0400, write EREC, P.O. Box 3048, Merrifield, Virginia 22116 or at

Return to the Spring 2000 Newsletter