FAQs

General Comment: most answers to questions about home energy use depend heavily on your personal situation -- the climate where you live, your energy usage patterns, home size, configuration and features. For this reason, we can give general guidance here, but for a more definitive answer you should use the Energy Advisor to assess your own situation. Not finding what you need here? Try DOE's Information Center.

General

1. What is the typical energy use of household appliances?
2. How can I save energy in my second home, which is unoccupied a large part of the year?
3. What's the most common mistake people make in trying to save energy around the house?
4. We don't own a home; we rent an apartment. What can we do?
5. We have an older house. Which should we do first: insulate or replace the furnace?
6. My neighbor's bills are much lower than mine, even though they have children, and are home more than we are. Why are my bills so high?
7. What's the single biggest user of electricity in my house?
8. I was trying to find an estimate of the expected savings of an ENERGY STAR New Home (30% better than Model Energy Code) versus an "average" existing home. Your estimates seem to be oriented to retrofits using Energy Star equipment, as was clear once I got into the details. Have you also done, or do you have a reference on the savings with the Energy Star new home? That would presumably come out somewhat better than the full retrofit case.
9. How about energy savings in my car?
10. What are the benefits of energy efficiency besides saving energy?

Heating, Ventilation and Air Conditioning

1. How much energy can I save by using fans instead of my air conditioner?
2. Should I use portable room heaters to lower my energy bills?
3. What information can you give me on air-to-air heat pumps for the home?
4. Does it pay to run a large duct from the outside of the house to the furnace to provide outside air for combustion? Contractors provided a passive supply of air along with the installation of our new furnace in St. Paul, Minnesota and we are wondering if it is worthwhile with a 30-year old furnace in Macomb, Illinois.
5. How can I tell if the contractor who is putting in a new furnace is gouging me on the price?
6. We have been very unhappy with our current heat pump and are wondering whether to install a new one or convert to natural gas. What factors should we consider?
7. If I shut off my heater or air conditioner when I'm gone from the house, doesn't it cost more to heat or cool the house back to the right temperature once I return?
8. Will installing a programmable thermostat reduce my heating and cooling consumption?
9. My central air conditioning blows cool but not cold air and seems to be always running. I have heard that dirty coils in the condenser could cause this. Is this something I can check and clean myself and, If so how would I go about it?
10. We are purchasing a new air conditioner and the contractor mentioned something about "duct sealing." What is this and would this be a good thing to do?

Comfort and Indoor Environment

1. On windy days I can feel drafts coming from the baseboards in my house. How can I stop these drafts?
2. Some parts of my house are never comfortable, no matter what I do. The rest of the house is fine, but one room is always too hot or too cold. Why is that, and what can I do to fix it?
3. I've heard that if we make our house too tight, the air won't be healthy to breathe.
4. I am trying to find some information concerning attic fans (i.e. the pros and cons).
5. We have condensation water drops on the vents that blow air into our living room. We have central air and we live in Wellington, FL. What could cause this condensation?

Windows

1. I keep getting ads in the mail for companies offering to replace our windows with "energy-efficient" windows. How much can these save me?
2. Over the winter, fog appeared between the panes of my double pane windows, but during the summer it went away. Why did this occur?

Water Heating

1. Is there any rating for electric water heaters? I would be interested in knowing the ratings for brands.
2. What is the average setting on an electric hot water heater?
3. If you turn your hot water heater off during the day, won't it cost more because you then have to heat up the whole tank and wait minutes before taking a shower? Also, isn't it kind of an inconvenience?

Computers

1. We're putting in a home office. Do computers and fax machines really use that much energy?
2. Should I leave my computer on all the time, or turn it off when not in use?
3. I have a Powermac 8500/180 and am wondering what I can do to lower its energy use. You mention that some new computers have Energy Star compatibilities. My computer was made in 1996. Please help, my energy bill skyrocketed the month I plugged the computer in.
4. Do you really think my answering machine uses more electricity than my computer?

Lighting

1. My utility company tried telling us to use more fluorescent lights to save energy, but I hate how fluorescent lights flicker when you turn them on and then make that annoying hum. And they make everything look sort of blue and cold. Isn't there anything better?
2. Is it better to turn lights off when you leave the room? I heard somewhere that it uses more energy to turn lights off and on than to leave them running.

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General

What is the typical energy use of household appliances?

Like most things in life, nothing's average, but here is a table showing what can be thought of as typical energy use for different appliances.

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How can I save energy in my second home, which is unoccupied a large part of the year?

There are millions of second homes in the United States. Some of these are owned by "snowbirds" who spend summers in the north and winters in the south, and many others with vacation homes. An unoccupied home that is not properly put in "standby mode" could cost well over $1000 if left alone for the one or more seasons.

For cold-climate homes, turning the heat off (or at least way down) while away is a natural starting point. Of course, preventing pipe freezing is essential but it may be able to be done without heating your home (e.g. with proper draining, and/or tape heaters wrapped to the pipes, toilets, and traps in key areas). If this is not sufficient then turning the heat way down (e.g. to 40-45 degrees) should provide adequate freeze protection at much-reduced cost. Roof-mounted electric heating elements used to melt ice dams may not be needed if your home is unoccupied and unheated, because snow will not be melting and refreezing at the eaves.

For hot-climate homes, the air-conditioning should be left off when away. With no one living in the home and indoor temperatures equilibrated with outdoor temperatures, less (no) water is generated in the house from activities like cooking and washing, and the risk of condensation and mold formation is minimized. Be sure to minimize sources of moisture in the vacant home. If moisture is a concern, having a humidistat wired in series with the thermostat would be prudent. In some cases a more energy-efficient humidifier may be used independent of full-on air-conditioning.

North or south, there are many other things to keep in mind. Water-heaters and refrigerators/freezers can be turned off (be sure to leave the doors ajar). All appliance transformers and power supplies should be unplugged (e.g., printers, computers, phones, television set-top boxes, halogen lights, fountains). And don't forget to shut off the spa. One or two indoor lights can be left on timers to help create the illusion that the home is occupied; there are probably even timers with random schedules. Outside lighting may be desired for security, but consider installing motion sensors so that the lights will only go on (temporarily) when movement is detected near the home - this lower use will also reduce the likelihood that security lights will burn out while you are away. Be sure, of course, that those lights that are left on are energy-efficient fluorescents.

In all cases, it is wise to have someone check the home periodically while you are away.

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