ROANOKE TIMES
Copyright (c) 1997, Roanoke Times
DATE: Sunday, February 9, 1997 TAG: 9702120025
SECTION: HOMES PAGE: D-1 EDITION: METRO
COLUMN: cut your utility bills
SOURCE: JAMES DULLEY
Q: We have an efficient house and I heard about "sick house syndrome." We use an air cleaner, but the air still seems stale. What is the best way to get fresh air indoors without pushing up our utility bills?
A: The Environmental Protection Agency has listed poor indoor air quality as one of the top five environmental issues in the United States. Ideally, a house should have one complete air change every two to three hours.
An unhealthy efficient airtight house can have carbon dioxide levels two to six times higher than outdoors. This can make one feel sluggish and sleepy. Other common pollutants come from household chemical cleaners, gases from furniture and carpets, plant spores, mold, cooking, even air fresheners.
Installing a heat recovery ventilator (HRV) with adjustable fans is the most efficient method to bring in fresh outdoor air year-round. The designs range from ducted whole-house models to portable window units. The small fans use about 100 watts of electricity - about as much as a light bulb.
Heat recovery ventilators use a heat exchanger core. In the winter, the incoming fresh outdoor air picks up heat from outgoing stale indoor air. The stale indoor and fresh outdoor air paths are sealed from one another.
HRV's typically save from 65 to 90 percent (efficiency) of the energy from the outgoing stale air. In the summer, the outgoing cool indoor air precools the incoming fresh air. If you have allergies, select a model with a prefilter for the incoming air. These filters are washable and reusable.
In hot humid climates or if you want to control mold and dust mites for allergy relief, select a model with an enthalpy (energy) heat exchanger. As it transfers heat between the air paths, moisture is exchanged, too.
Small window units are the easiest to install. These lightweight units mount in windows like air conditioners. Larger through-the-wall models are also easy to install. The fresh air gradually circulates throughout the house.
Whole-house models can be ducted into your existing furnace ducts or have their own duct system. The stale air intakes are often located in the bathrooms, kitchen and laundry. The fresh air outlets are in the living room, dining room and bedrooms.
There are several control options for the fans in a HRV. A variable-speed adjustment provides the most precise control. Most HRV's can also be set for timed operation. In humid areas, choose one with a humidistat control. The incoming and outgoing fan speeds are balanced for the best ventilation.
For a buyer's guide of 21 whole-house and window HRV's listing air flow rates, heat exchanger types, efficiencies, warranties, prices and a size selector chart, write to James Dulley, The Roanoke Times, 6906 Royalgreen Dr., Cincinnati, Ohio 45244. Ask for Update Bulletin No. 559 and include $2 and a business-size self-addressed stamped envelope.
To rush bulletin delivery or read 150 previous columns, visit the Web site: www.dulley.com
LENGTH: Medium: 58 linesby CNB