Furnace fan 'summer switch' may be better at other times

Q. How helpful is it to run the furnace fan so as to circulate air through the house when the furnace is not in use? Our summer climate is hot and humid. I feel we should run the furnace fan most of the time, but my husband contends that this practice would cause needless wear on the furnace, besides wasting electricity. What do you say? Margaret Burr Zephyrhills, Fla.

A. I'll not take sides personally, but only attempt to convey some facts about summer switches, yea or nay.

Summer switches on forced-air furnaces help cool the house primarily and ideally when the outside temperature is lower than that inside. Even warm air circulated inside the house can provide a sensation of coolness, but at the expense of a possible warm-air buildup toward evening.

The cost of operating such a fan is modest. Ask your local electric utility company for an estimate of energy cost per hour. Give the utility the size and electrical draw of the unit.

Use of the fan naturally brings on wear, but air-handling units last for many years, even when summer switches are used regularly.

The hot, humid Florida days and nights may confirm your husband's analysis of eliminating some summer use of the fan. Your analysis is accurate in the three other seasons, when the nights are cooler than the days.

Ideally, use a summer switch to bring in desirable outside cooler air. Minimize its use when only the warmer outside air is available. In the latter case, try oscillating-bladed fans for greater comfort in occupied rooms.

It goes without saying that about the only alterntive in a hot, humid climate is mechanical air conditioning.

Indeed, it is the only sure arbiter between the Burrs.