The Basics of Good Ventilation
Have you ever gone up to your attic in the summertime and been stunned by the heat? It’s surprising, but it can get pretty hot up there even on a mildly warm day. If you’ve noticed this, your home may have inadequate ventilation.
What is ventilation, and why does your house need it? Ventilation is the process of moving outside air throughout your house. Without proper ventilation, your home consumes more energy and the roof deteriorates faster. Even worse, it your house is at risk of building up moisture that attracts wood-boring insects such as termites and carpenter ants and also sets up a perfect growing environment for mildew and mold, which can be harmful to your health.
Let’s take a look at some of the common ventilation problems in three areas of your house—the foundation, kitchens and bathrooms, and the attic—and what you can do about them.
The Foundation
Take a walk around your house, and look at the foundation. You should see some rectangular openings that are covered by a grill of some kind. These are foundation vents, which allow air to move under the house. If your house has a basement, you’ll find them only under the porch. If you have a crawlspace, they should be around the whole foundation.
Have a look in the crawlspace or under the porch for a vapor barrier. This is a sheet of plastic that covers the soil under the house, and it’s there to prevent moisture in the soil from evaporating and rising up onto the framing. This can lead to dry rot, insect damage, and mold. (These are all part of the natural process of wood decay, which is great on the forest floor, but not so great under your house.)
If your crawlspace or basement does not have proper vents, or if there are no moisture barriers on them, you should install proper ventilation as soon as possible. A poorly ventilated basement is a prime candidate for mold and mildew problems.
Kitchens and Bathrooms
Wherever there’s water that steams up, like kitchens and bathrooms, exhaust fans are a great way to get rid of excess moisture. If you have a recirculating fan over the range (the kind that sucks air through a filter and sends it back into the room) you should consider installing a ducted fan instead. This will remove the moist air and send it outside.
You should definitely have an exhaust fan in the bathroom, and use it every time you shower or take a bath. If your exhaust fan is so loud that you don’t ever use it, consider getting a new one; there are some pretty quiet ones on the market.
The Attic
If your attic gets really hot in the summertime, chances are you don’t have enough ventilation, or the system isn’t working right. For example, the air pathway may blocked by insulation. Here’s how it’s supposed to work: warm air is drawn into vents in the soffits (the horizontal areas directly behind the gutters). From there (remember, hot air rises) it moves up and out the ridge vents (square plastic things along the peak of the roof). This airflow keeps the temperature down. It also helps remove moisture. Some houses are equipped with fans in place of vents to increase the flow of air.
How many vents you need depends on a lot of factors, like roof design, the location of your house and amount of direct sunlight it gets. However, a minimum venting system should have one square foot of roof vent area for every 300 square feet of attic area. To learn more about ventilation, check out this guide to energy efficiency from the U.S. Department of Energy. And if you think you have a mold or moisture problem in a poorly ventilated area of your home, contact us for information about mold testing.
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