COPYRIGHT 2018 JAMES DULLEY ( www.dulley.com/sea/ ) - March 2018 - (graphics ref. No. 404u at www.dulley.com/sea/column/2018-mar.htm 

"Maintain an efficient, comfortable, healthy indoor humidity level year-round"

Dear Jim: I have lived in hot and cold areas and had indoor humidity problems in both. What is an efficient, comfortable humidity level and how can I maintain it year-round? - Steve W.

Dear Steve: Humidity-related problems are generally worse during winter in the north and during summer in the south, but there can be year-round problems everywhere. Indoor humidity levels can be controlled by just opening windows or running the furnace or air conditioner more, but these options increase your utility bills and waste energy.

There is not just one ideal indoor humidity level. When referring to personal comfort, a target of 40 to 45 percent relative humidity is good. Most people are comfortable with a relative humidity ranging from 30 to 50 percent and can tolerate 20 to 60 percent. With relative humidity in the proper range, your furnace or central air conditioner thermostat can be set down or up respectively to save energy.

When the relative humidity level is too high, there can be serious health problems related to allergies, dust mites, mold, mildew, and other harmful microbes. Being at the other extreme with relative humidity too low, a person's mucous membranes may dry out which increase the susceptibility to cold and respiratory illness. Also some nasty microbes prefer excessively dry air.

To understand how to control indoor humidity year-round, it is important to understand the term "relative humidity" or RH. Warmer air can hold more water vapor (moisture) than can colder air. If the air at 75 degrees has a RH of 50 percent, it means the air is holding 50 percent of the maximum amount of water vapor it can hold at that temperature.

If that air drops to 50 degrees, that same amount of water vapor may now be 70 percent RH. When the air gets cool enough, next to window glass during winter or the refrigerator door seal during summer, it reaches a point where the air can no longer hold that much water vapor. This is called the dew point. This is when your windows or refrigerator door sweat.

You can purchase an inexpensive hygrometer at most hardware stores to measure to indoor relative humidity. Since you are having humidity-related problems, your best gauge of the proper relative humidity is when the problems are alleviated or, at least, tolerable.

For example, if you have old single-pane windows in the north, you would have to get the relative humidity level to an uncomfortably low level to avoid all window condensation on cold winter nights. In the south, it may not be possible to stop all mold and mildew in the bathroom even if you run the vent fan and your central air conditioner almost continuously.

The keys to maintaining a comfortable and efficient indoor humidity level are controlling the sources of moisture and ventilating them efficiently. The average person gives off one-quarter cup of moisture per hour just breathing. Cooking for a family of four produces five cups of moisture per day. A shower contributes one-half pint and a bath contributes one-eighth pint.

Exterior moisture sources are leaky roofs, plumbing, windows, doors, etc. Once you have taken care of these problem areas, check the slope of the ground around your home. It should slope slightly downward away from the house walls. Even with the best new windows, soggy soil around your home allows excess moisture to migrate indoors year-round.

Installing new efficient replacement windows or exterior storm windows is the best method to control a window condensation problem efficiently. This also saves energy during the summer cooling season. With more efficient glass, you should be able to close insulating window shades at night to save energy. With old windows, closing shades exacerbates condensation problems.

Install new bathroom vent fans with humidity sensors. These come on automatically and run until the humidity level drops. With a manual switch, you have to either turn it off prematurely when you leave for work or let it run all day. Check the seal around the clothes dryer duct leading the outdoor vent.

Install a new furnace/heat pump with a variable-speed blower and compatible thermostat to allow it to run in an efficient dehumidification mode during summer. Make sure the damper handle on the central humidifier is set for the proper season. Use electric countertop cookers and vegetable steamers in the garage instead of in the kitchen during summer. I use an outdoor solar-powered steamer on sunny days.

Dear Jim - I just bought an old electric range that I am going to put in my son's apartment. Is there anything that we can do so it uses less electricity? - Kelli H.

Dear Kelli: Electric ranges are very simple devices. Check to make sure that all of the burner (element) controls work properly and actually adjust the heat from low to high. Also clean the chrome reflector drip pans or buy new ones. They are very inexpensive and can improve its efficiency.

Check the accuracy of the oven thermostat with a thermometer. If it gets hotter than the setting, this wastes electricity. Check the gasket around the oven door. If it has deteriorated and is leaky, you can replace it.

Send inquiries to James Dulley, Publication Name, 6906 Royalgreen Dr., Cincinnati, OH 45244 or visit www.dulley.com.