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The Sensible Home

Super-Efficient Air Conditioner Saves Money


QUESTION: Our 10-year-old central air conditioner does not keep us as comfortable as it used to, and our electric bills are high. What's new for 1996, and will installing a new high-efficiency model improve comfort too?

ANSWER: Installing a new central air conditioner can lower the cooling portion of your utility bills by up to 40%. Even if your old air conditioner still works, you may save money overall by installing a new one now.

The improvement in comfort from installing a new super-efficient air conditioner varies with the various designs. Do not simply select the unit with the highest efficiency rating if comfort, along with lower electric bills, is a concern.

The newest super-efficient multilevel output central air conditioners offer the best comfort. These have sensors and microprocessors that constantly fine-tune the cooling output to the changing comfort conditions in your home.

In the super-efficient low-output cooling level, the air conditioner runs longer. This keeps cool air slowly circulating, and the blower runs at a quieter low speed. It also cleans the air better for allergy sufferers.

The best three-level models use two sizes of compressors. During mild weather, only the small compressor runs. In moderately hot weather, only the medium-size compressor runs. In severely hot weather, both run.

Two-level models that use a single two-speed compressor are also available. Eighty percent of the time, these run at the super-efficient low speed. The controls automatically sense when to switch to the higher speed.

The most reasonably priced super-efficient air conditioners use a one-level compressor design. These have efficiency ratings as high as the multilevel designs and save almost as much on your electric bills.

Many new central air conditioners use scroll compressors. These are very efficient, trouble-free and quiet. This unique compressor design uses a simple wobbling mechanism instead of a reciprocating piston. Fewer moving parts are needed, and it actually operates better the older it gets.

Some single-speed and all multilevel air conditioners use variable-speed direct current blower motors. These use less than half as much electricity as a standard blower motor, an extra savings of as much as $300 a year.

Variable speed allows for soft start of the blower. Instead of hitting full speed at once each time it comes on, a variable-speed blower ramps up slowly to full speed. This is quieter and cuts down on drafts year-round.

Write for Update Bulletin No. 510 showing a buyer's guide to 22 super-efficient central air conditioners listing efficiency ratings, comfort features, output levels, types of compressor and blower motors, warranties and a payback savings chart. Please include $2 and a business-size self-addressed stamped envelope. Send request to James Dulley, Los Angeles Times, 6906 Royalgreen Drive, Cincinnati, OH 45244

Q: My refrigerator is about 12 years old. The door squeaks when it opens, and the door gasket looks pretty bad. Is the "dollar bill" test a reliable method to check the gasket?

A: By a "dollar bill" test, I assume you are referring to closing the door on a dollar bill. If it stays in and feels tight when you tug on it, the door seal is OK. This is not a real accurate evaluation.

If the dollar falls out, the seal obviously needs to be replaced. A better check is to inspect the gasket in the summer. A leaky gasket tends to sweat and becomes discolored. Check any discolored spot for a weak seal.


Letters and questions to Dulley, a Cincinnati-based engineering consultant, may be sent to James Dulley, Los Angeles Times, 6906 Royalgreen Drive, Cincinnati, OH 45244.

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