Energy Adviser: Steps can keep mold from taking hold in the home



Mold loves paper and wood, so it’s little wonder that people with sensitive noses start sneezing when they put up their fresh-cut Christmas trees. If mold gives you the sniffles, you’re probably looking forward to taking down the tree after the holiday.

For some households, however, mold can become a more perennial problem.

One-third of Northwest homes have visible mold inside, according to research by George Tsongas, a consulting engineer and professor emeritus at Portland State University.

Although mold can damage your home and pose a health hazard, it’s important to keep perspective.

“There are mold spores everywhere. Every breath you take has mold,” said Bob West, a Clark Public Utilities energy counselor. What you don’t want is those spores growing colonies in your home.

“If you have warm, moist air inside the house, when it hits a cold surface, it will condense and give mold something to grow on,” West said.

Where does that indoor moisture come from? Look in the mirror.

“If you go to a cold piece of glass and exhale once and see how many drips of water you get, you see how much moisture one breath generates. All that gets into the house and it’s hard to get out,” West said.

The typical family expels 3 gallons of water into the air a day, according to Tsongas’ report.

Master bedrooms can be trouble spots, given the combination of a bathroom and a bedroom. Add a closet with a cool outside wall, and you’ve got prime mold breeding grounds.

The trick is to keep moist areas well-ventilated. Tsongas recommends keeping indoor relative humidity below 50 percent, or better yet, between 30 percent and 40 percent. You can measure the relative humidity with a hygrometer, which you can find at a big box store for less than $30.

Lowering the indoor humidity and reducing condensation may require using more energy, but it’s worth it to prevent mold growth.

Here are some steps you can take:

• Use ventilation fans in the bathroom and kitchen until moisture completely clears the room. That takes longer than you think — hours, not minutes. If the fan in your kitchen just re-circulates air, replace it with one that vents outdoors.

• Use louvered doors for closets on exterior walls.

• If you turn down the thermostat at night, consider keeping it a degree or two warmer.

• Although it saves energy to shut off heat to unused rooms and keep their doors closed, avoid doing so if you notice mold growth.

• Move furniture back from external walls to allow air to circulate.

• Open shades and blinds during the day. Wipe off any moisture you notice on windows, and clear out any organic debris (that is, dead bugs) that you notice in the tracks.

• Reduce the number of indoor plants, and keep less firewood in your house.

• You may need to use a portable dehumidifier, especially in a moist laundry room.

“If you find a mold issue, clean it up quickly and ventilate the area,” West said.

Wash the surface with a soap solution, rinse with plain water and then dry it, Tsongas recommends.

West said you can use bleach to remove the stain, and then wipe the area with vinegar to prevent mold from growing back.

You’ll want to seek professional remediation for mold that covers more than 10 square feet, according to Tsongas’ report. But if the patch is smaller, go ahead and tackle it yourself.

Energy Adviser is written by Clark Public Utilities. Send questions to or to Energy Adviser, c/o Clark Public Utilities, P.O. Box 8900, Vancouver, WA 98668.