The Department of Commerce encourages Minnesotans to keep furnace exhaust vents, air intake hoods, and chimneys clear of snow and ice in order to keep the heat on and prevent carbon monoxide poisoning.
Homeowners with high-efficiency furnaces and other vented combustion appliances may have air intake and exhaust vents that exit the home through an exterior sidewall rather than a chimney. Water heaters, clothes dryers, and air-to-air heat exchangers may have similar sidewall vents. If the vents are covered by snowfalls or drifts, it may prevent the fresh air intake needed to operate the appliance. Some furnaces will shut off automatically if intakes or exhausts are smothered by snow and ice. However, for those that continue to run, carbon monoxide (CO) can build up in the home and cause a very dangerous situation. CO is a colorless, odorless gas that can be lethal.
To prevent the dangerous backdrafting of CO and to help keep your combustion appliances operating safely:
• Make sure CO detectors are working throughout the house. Minnesota law requires CO alarms in every single-family and multifamily dwelling.
• Keep vents clear and free of snow and ice. Check them regularly.
Minnesota building code requires that intake and exhaust vents be located not less than 12 inches above ground to prevent clogging. Also, buildup of snow and ice on gas and electric meters can cause them to malfunction; utilities recommend keeping them clear.
A well-functioning, older, less-efficient furnace that vents through the chimney will usually create exhaust temperatures that are hot enough to melt any snow that might collect on the chimney. But it’s a good idea to check chimneys and rooftop vents (such as on mobile homes) to make sure they are not snow clogged. If you suspect a problem, clear the snow if it can be done safely or hire a snow removal pro.
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Minnesota Energy Tips is provided twice a month by the Minnesota Department of Commerce, Division of Energy Resources. Contact the division’s Energy Information Center at email@example.com or 800-657-3710 with energy questions.