|Don's Home Home - Garden|
Research indicates that for health and comfort, a relative indoor humidity of 40 to 60 percent is desirable.
Some say 35%-45% is the ideal level.
Less than 60% in the summer and between 25 - 40% in the winter.
Humid air makes you feel warmer.
This range will provide the best comfort for your family, while helping to protect your musical instruments, drywall, wooden furniture and other belongings or materials from the damaging effects of dryness or excessive moisture.
In winter, however, that level can drop to 10 percent.
When outside temperatures drop below 20¡ F, even a 30 percent indoor humidity level can lead to window condensation. So you might not be able to run a humidifier when it gets that cold.
Also be cautious about adding too much humidity to the air. When humidity exceeds 55%, it's the perfect climate for bacteria, mold, and dust mites to grow. A good rule to remember is that there should not be condensation on a cold window or windowsill from the humidifier or vaporizer.
Water or ice will appear on windows, and if there's moisture on windows, it's also likely to be collecting, unseen, in wall and attic cavities. A few seasons of that, and building materials -- sheathing, studs and woodwork -- will begin to rot.
The following list, supplied by the Minnesota Department of Public Service, is based on a double-glazed window and an indoor temperature of 70 degrees. You will notice that the lower the outdoor temperature, the lower the indoor humidity should be.
My experience with room temperature of 60° and double-glazed windows.
If you are building a home or remodeling, demand high-quality windows. They should have U-values of 0.35 or less. Such windows are less prone to cold-weather condensation and icing, which means that indoor humidity can be higher.
Humidifiers and Colds:
One of the first things most pediatricians recommend when a child comes down with a cold is running a humidifier to help ease congestion.
At Humidifiers Don't Do Lick Of Good Helping Colds : NPR they say they don't help.
Warm air holds more moisture. Relationship between relative humidity (RH) and temperature. Formulas 50°F 75% 55% 68°F 40% 30% i.e. If the humidity is 75% at 50° and you increase the temperature to 68° the humidity will go down to 40% My test 57°F 45% 70°F 32% ________________ 48°F 48% 59°F 40%Rule of Thumb : Relative humidity doubles with each 20 degree (Fahrenheit) decrease, or halves with each 20 degree increase in temperature.
Source: Temperature-Moisture Relationship - Utah State
Wood swells and contracts depending on it's moisture content. It gets smaller as it dries out, parts of the instrument like the top are under tension, the perfect condition for the formation of cracks and failure of the joints and seams.
My Vornado humidifier which was supposed to shut down when the humidity hit a preset level thought the humidity was between 40 and 45% when it was 52%.
David Burgess of
BurgessViolins.com says "I've tested probably 50 hygrometers, and ONLY ONE was within two percent of the correct reading."
How to test/calibrate a Hygrometer: