New dryers need no outdoor vent

Q: I need a new clothes dryer. Now, the clothes take a real beating and come out wrinkled and tangled. How effective and efficient are the no-outdoor-vent designs and what new features should I consider? -S. B.

A: Using a no-outdoor-vent clothes dryer design (common in Europe) can reduce many indirect energy costs of running a typical outdoor-vented dryer. Most no-vent models use many surgical stainless steel parts and they can literally last a lifetime. Since no outdoor venting is needed, these dryers can be located anywhere in your house, even in a closet.

A clothes dryer is a major household electricity consumer. Not only does it use energy to heat the air that dries your clothes, but it sucks already-heated or cooled air out of your house for a double energy expense. Outdoor vent covers are typically very leaky and may be a source of bugs and allergens inside your home.

By keeping the dryer heat indoors in the winter, the heating load on your furnace or heat pump is reduced. In the summer, the air-conditioning load from the extra heat is offset by the elimination of hot humid air infiltration. Remember, in the summer, run your clothes dryer late at night or very early in the morning to minimize the peak electricity demand.

Instead of drawing heated air through the clothes and venting it outdoors, a no-vent dryer uses a simple condensing process to dry the tumbling clothes. Air inside the dryer is heated and circulated through the damp clothes. Since it is warm air, it absorbs moisture from the clothes as it dries them.

This warm damp air now circulates through a small heat exchanger built into the base of the dryer cabinet. Another small quiet fan draws room air in through separate passages in the heat exchanger. The two air flows do not mix and no conditioned indoor air is lost outdoors.

This room air cools the warm damp dryer air causing the moisture to condense into a tray. This dryer air is reheated and circulated through the tumbling clothes again to absorb more moisture. When the clothes are dry, you slide out the water tray and empty it. It is basically distilled water that you can use on your plants. For greater convenience, install a tube kit to run the condensed water to a drain.

Another drying option is a combination clothes washer/dryer, all-in-one space-saving cabinet (also popular in Europe's smaller homes). Most use the no-vent condensing drying process. These are very convenient to use. You put in dirty clothes and take out clean dry clothes an hour or two later.

The key to energy efficient and wrinkle-free clothes drying, in a no-vent or conventional vented dryer, is not over drying the clothes. Generally, use an automatic moisture-sensing cycle instead of a timed cycle for the best results.

A reversing-rotation drum (typically reverses direction every several minutes) is another feature that reduces wrinkling and provides fast uniform drying. After the clothes are dry, a "wrinkle-out" option tumbles them briefly every few minutes, for up to an hour, until you have time to remove them.

Another efficiency and convenience option is a super-large (100 load) lint basket. This can reduce inefficient air flow resistance through the dryer when you forget to empty it regularly.

Also, to reduce your drying electricity costs, do loads consecutively to take advantage of the residual heat in the dryer. Separate your clothes and do not add wet clothes to a partially dried load. This can trick the moisture sensor into over drying the clothes.

Write for Utility Bills Update No. 823 - buyer's guide of the most efficient no-vent, standard-vented dryers and combination washer/dryers, moisture sensors, drum rotation, features, prices and efficiency tips. Please include $2 (with checks payable to Jim Dulley) and a business-size SASE. Mail to: Jim Dulley, Illinois Country Living, P.O. Box 3787, Springfield, IL 62708. To instantly download, go to http:// www.dulley.com.

James Dulley is a mechanical engineer who writes on a wide variety of energy and utility topics. His column appears in a large number of daily newspapers.

Copyright 1998 James Dulley

18 ILLINOIS COUNTRY LIVING JUNE 1998