QUESTION: It seems that the newspapers are filled every day with ads for energy-saving appliances and products. I'd sure like to lower our utility bills by buying some of these products, but our appliances are all working fine. How do we know when it makes sense economically to get rid of what we have and buy new products?ANSWER: Great question. I think a two-part answer will give you what you're looking for.First, even though your current appliances are working fine, how old are they?Major home appliances typically last 15 to 20 years or more, and it's not uncommon to find people who have appliances years older than this and they're still working.My opinion is that if your kitchen appliances and washer and dryer are around 10 or more years old, then give some serious thought to buying new ones.There have been great improvements in energy-efficiency standards in recent years, and newer appliances operate on a lot less energy, meaning new ones will pay back their purchase cost over their lifetime and save you even more money over time.By the way, please resist the temptation to buy a new energy-efficient refrigerator and put the old one, which is still working, in the garage or basement. It might seem like a good idea when you first think of it, but that old unit is an energy-guzzler that will be terribly inefficient to keep when you don't really need it anymore.Odds are very good buying a new one for the garage will be much cheaper in the long run than keeping the old one out there.Second, if your appliances aren't terribly old, there are some things you can do to make them as efficient as possible and keep them operating that way. Here are a few tips for you:• Clean the refrigerator coils at least once a year. Make sure the temperature settings are correct (refrigerators should be set around 36 to 38 degrees and freezers between 0 and 5 degrees).• If your refrigerator doesn't have an automatic defrost feature, you should manually defrost it on a regular basis to prevent ice from building up on the interior coils.• Don't put furniture, drapes or other things in front of air vents that can block the airflow from your heater and air conditioner.Keep the vents, baseboards and radiators clean. Clean the filter on your clothes dryer before every use.Check the filters on your heating and cooling equipment monthly and change or clean them when needed.Ken Sheinkopf is a communications specialist with the American Solar Energy Society (www.ases.org). Send your energy questions to askken@ases.org