The average relative humidity in Boston is about 56%.
That's certainly not the dampest place in the US—New Orleans is 86%—but combined with our rain, snow, and temperature changes, it's safe to say our homes have to deal with a lot of moisture.
What does this do to your home, and what can you do about it?
A damp house is a damaged house
When warm, humid air meets a cooler surface, you get condensation—in other words, water. This water can run down a window or an uninsulated wall or pipe and into the structure. Sitting in the walls or basement, over time this water contributes to problems like
-
peeling paint
-
peeling wallpaper
-
mildew
-
black mold
Allergens and bacteria don't even need to wait for condensation to occur. They grow quite happily in a humid environment.
How much humidity is too much?
Experts say anything between 40% and 50% humidity is a pretty good mark.
If the house is too dry, like below 30%, it will be uncomfortable to live in. Dry mouth, dry skin, and static electricity zaps are no fun. Consider a humidifier if that's your situation.
But if you're above 50% humidity, your house is creeping up into the zone where moisture is likely to start problems.
Keeping the house happy
Take the following steps to reduce moisture and humidity in your home.
-
Fix any leaks as soon as possible.
-
Insulate pipes.
-
Vent bathrooms, water heater, washer/dryer, and kitchen appropriately. Cooking, showering, and doing the laundry all increase the moisture in the air.
-
Keep your heating and cooling system in good shape. An annual cleaning and inspection of a forced-air furnace should cost $100, more or less.
-
Consider a portable dehumidifier unit if you have a room that causes more concern. These can cost anywhere from $50 to $250 depending on size and quality. Humidifiers and dehumidifiers and their filters need to be kept clean!
You can also take practical steps such as taking cooler showers. Some houseplants like ferns and cacti also take water out of the air.