WHEN the heat and humidity of summer take hold and it’s time to hit the “cool” button, you’ll want your air-conditioner to respond with a blast of chilly air and a satisfying hum.Doing some maintenance now can help make sure that happens.The first step, albeit a simple one, is often overlooked: Make sure the unit isn’t still wearing its winter coat, advised Richard H. Toder, executive director of T/S Associates, a Manhattan heating and air-conditioning company. “You wouldn’t believe how many people forget to take off the cover and end up burning their unit out,” he said., a home-improvement Web site.Look to see that weeds or bushes have not grown too close to the compressor, he said, and that no debris has been sucked up into the coil. The compressor should have at least a few feet of clearance around and above it, and its fins — a series of thin metal strips like those on the back of a window air-conditioner — must be free of dirt and debris.Next, remove the unit’s filter and either clean or replace it.

If the filter isn’t clean, the workings can become caked with dust, significantly reducing the unit’s efficiency. In window units, the filter is either a custom-fit plastic-framed fiberglass filter that can be washed and dried, or a plain foam one that Mr. Toder says should be replaced instead of cleaned. Buy a new one at a home center or hardware store for a few dollars and cut it to size.In central air systems, the filter is in the air handler, which is typically in the basement or attic. The filters — which often are also the furnace filters — come in specific sizes and can be found in hardware stores or home centers.“You don’t have to get a really expensive filter, as long as you resolve to change it every 30 days,” Mr. Carter said. A medium-price filter, costing about $5, is probably sufficient, he said. Most experts say it’s also important to clean the inside of the unit — particularly the evaporator coils, which look like a coil of copper tubing — with a vacuum cleaner or a soft brush.

With a window unit, that may involve removing the front cover to get to the coil; with a central air unit, you may need to take the cover off the housing of the evaporator coil. If that seems too complicated or difficult, call a professional.Peter Varsalona, a principal of Rand Engineering & Architecture in Manhattan, said that air-conditioners installed in sleeves through the wall — as in many apartments — can usually slide out of the sleeve and be cleaned.how much is a new 3 ton ac unitOnce clean, the air-conditioner can be tested to make sure it still cools adequately. how much do 3 ton ac units costFor a window unit, the test couldn’t be more simple. how to recharge wall ac unit“Wait until the temperature is about 70 degrees outside, turn the unit on, wait a couple of minutes, and if it’s blowing cold air, it’s working,” Mr. Carter said.

Tom Kraeutler, a co-host of the syndicated radio program “The Money Pit,” offers a relatively simple test for a central unit. Once the outdoor temperature reaches about 60 degrees, turn the unit on, let it run for 10 to 15 minutes, then put one room thermometer near a vent where the air is coming out, and another at one of the return vents, where air is pulled back to the unit.“What you are looking for is a 12- to 20-degree difference between them,” he said. If you don’t find that, he said, the unit could be leaking coolant and should be checked by a professional.John Proctor, president of Proctor Engineering Group in San Rafael, Calif., offered a few suggestions for using a central air system efficiently. Set the fan on auto, so that it comes on only when the unit is cooling the air, he said, and resist the urge to close exhaust registers in unused rooms. The system will operate more efficiently with all the registers open, he said. & the Energy Spy Insider Free eNewsletter

The leaves are beginning to turn and it's time to winterize your home. When you must take a two liter bottle of warm water out with you to rinse the windshield before you can see where you're going, it's time to winterize your home and it's time to park your car in the garage. I always preferred the bottle of warm water over starting the car and letting it warm up for hours. I just don't feel right letting the car idle that long, using all that gas and getting zero miles-per-gallon, when a little warm water will do the job. Of-course, I live in a mild winter area compared to many of you folks, I do understand that some of you live in a winter wonderland that will freeze the warm water on your windshield faster than the windshield wiper can sweep it off. Here are five improvements that will help winterize your home against the cold weather. Keep the cold wind from winterizing your floor. Remember the schedule for foundation vents, open in spring, closed in fall. Let the underfloor area breath through the summers warmer months and dry out, then close the vents in the fall to keep the cold air from freezing your feet.

I have the plastic, rectangular vents at my place. The vents have the plastic flaps that open and close.  With the passing of time, some of the flaps will no-longer stay closed, so I have purchased the styrofoam vent covers and placed those in front of the flimsy plastic ones. Now the flaps are held closed and I have double, insulated protection against the cold. The styrofoam vent covers can be easily trimmed to fit most vent openings. No matter what type of heating system you’ll be relying on this winter (furnace, wood stove, boiler, heat pump, etc.), it’s important to have your system cleaned and serviced. Of special note is the air conditioner heat ex-changer. If you have central air conditioning or a heat pump, somewhere in your duct system near the furnace is the heat ex-changer that is connected to your air conditioner or heat pump. The heat ex-changer looks like your cars radiator. During the summer it has all that cool air flowing through it along with the all the dust, particles, animal hair, Q-tips, and anything else you can't find.

Open up the heat duct and gentle vacuum and clean the heat ex-changer. All your warm air that heats your home also must go through this radiator, remember, if the radiators plugged up, the car overheats because not enough air can pass through. If the warm air can't pass through the heat ex-changer, your feet stay cold and your utility bill heats up. Don't allow the warm air that you have already paid for leak and radiate up through the ceiling. Attic or ceiling insulation is the most cost effect measure you can treat yourself to that will save energy and keep your home more comfortable. Remember, first air seal the attic floor and then insulate. How much insulation should you have in your attic? Simply, the more the merrier. If your on a short budget like I am, air seal and insulate the attic yourself. Most of the big-box building supply stores will have the machine to blow the insulation into your attic and you can use the machine without additional cost. The kids have been opening windows and running in and out the doors all summer.

There is a pretty good chance that the windows are not shut all the way and the weatherstripping in the doors have been damaged. Check the windows and see that they are closed properly and latched. Latching a window will help the weatherstripping do it's job. If you have a problem window that has damaged weatherstripping, the weatherstripping can be replaced. You don't have to replace the whole window just because the weatherstripping is hanging out. Not everybody can have central air conditioning. For many of us, the Amana A.C. unit sitting in the family room window is as good as it gets. So what happens when the snow starts to pile up on the backside of the Amana? The air conditioner is an open tunnel with a bunch of fins in it. Even when the fan is not on, the air can pass through the unit almost unrestricted. The window air conditioner needs to be removed from the window and the window closed and latched. Some homeowners and builders get fancy and install a window air conditioner straight through the wall.