Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, June 21, 1994 TAG: 9406290018
SECTION: EXTRA PAGE: EXTRA6 EDITION: METRO
SOURCE: David Butler
DATELINE: LENGTH: Medium
A: Although bringing in outside air during the coldest and hottest months can lead to slightly higher energy bills (when compared to an air-tight home), the alternatives are even less appealing. Natural ventilation, as you discovered, wastes energy and compromises comfort. What you may not have realized is that uncontrolled infiltration often leaves moisture and mildew inside your walls. This reduces insulation effectiveness and may even lead to structural damage.
Now that you live in a nearly air-tight home, you need to consider its effect on the air you breath. Without ventilation, your home will accumulate carbon dioxide and moisture along with a variety of odors and toxins - all by-products of everyday living. Some of the worst offenders include food and pet odors, carbon monoxide and smoke from tobacco and cooking, and fumes from cleaners, furniture and building materials. Poor ventilation also promotes the spread of allergens, bacteria and viruses.
The EPA has identified indoor air quality as one of the five most urgent environmental problems facing our nation. In fact, for a growing segment of the population, poor indoor air poses a greater health threat than does pollution from factories or cars. Few people anticipated that today's energy-conscious building techniques would have such negative consequences. The solution is fresh air. The problem is how to get it.
On all but the nicest days, outdoor air needs to be heated or cooled as it's brought into the home. That takes energy - the very thing you're trying to save. However, each cubic foot of air brought in must displace an equivalent amount of conditioned air. A small air-to-air heat exchanger can transfer energy from the warm exhaust air to the fresh incoming air and visa versa during the summer.
A growing number of companies produce whole-house ventilation systems with a heat exchange mechanism. They're commonly referred to as heat-recovery ventilators (HRV) or energy-recovery ventilators (ERV). Some models are more than 90 percent efficient and consume only about as much electricity as one or two light bulbs!
Using the existing ductwork, an ERV can easily be installed in an existing home. If your home has baseboard heating, you can greatly improve air circulation by having a ducted ERV installed. Some are even designed to work in tandem with existing bathroom and kitchen exhaust fans. In new construction, you may want to give your ears a break by using an ERV in lieu of individual bathroom fans.
If you live in an extremely cold climate, you'll need an ERV with a defrost mode. Some models include a small preheater for sub-zero weather. Those who must endure hot, muggy summers should consider an ERV that transfers water vapor along with the heat. This serves to moderate indoor humidity during the winter and summer. By maintaining relative humidity at a comfortable level throughout the year, you can actually reduce the load on your heating system!
To receive a list of companies that manufacture whole-house energy-recovery ventilation systems, please send $1.50 and a self-addressed envelope to David Butler F-405, Department TWN, 14713 Pleasant Hill Road, Charlotte, N.C. 28278-7927. The list includes phone numbers and a summary of each company's products.
Q: I recently saw an ad for something called Photo CD. Could you please explain this?
A: A growing number of companies are set up to transfer images from conventional film to a 5-inch optical disk similar to an audio CD. Using a special CD player, you can view the photographs on a conventional TV set. One disk holds 100 images (they don't all have to be added at the same time).
by CNB