on to boil in the kitchen will raise the R.H. in the entire house, assuming you have not turned on the ventilation fan.

During the summer months a lower R.H. is needed for comfort and health. The human body needs to give off heat. This rate of heat loss depends on the age of, and amount of work being done by, the occupant. When air temperatures start to exceed 85 deg. F., the major mechanism for heat loss is through perspiration. This perspiration must evaporate to do its job. If the R.H. is high, the rate of evaporative cooling is low. This results in discomfort at best and heat stroke at worst. It has been my experience that R.H. should be kept at 30 to 40% if possible.

In some climates this would be impossible without dehumidifiers during extreme conditions. Even under extreme conditions, the tight home has the advantage. Ventilation of the structure can occur during the most favorable time, usually early in the morning before the sun rises. Then during the worst part of the day, the home can be closed to a minimal venting mode and retain the dryer, cooler air for comfort. This would save money on the installation and operation of dehumidification equipment or grossly oversized cooling systems.

Comfort is important, but there are other considerations when dealing with excessive humidity. Dry rot is an insidious destroyer of property. I have visited homes with major dry rot damage caused by the owner blocking vents with material packaged and sold for just that purpose. This unconscionable retailing practice must stop.

I have had owners tell me they open the vents in the summer, only blocking them in the winter. The winter is when all the damage occurs due to higher moisture content of the ground and the greater temperature differential between the interior and exterior air. This, in fact, mimics the survival