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Should I Close the Vents in Unused Rooms to Save Energy?

small_4753578952Given the fact that you have the ability to shut individual air vents in your home, you might be tempted to close off the vents in rooms that you don’t use very often in order to save energy. But as it turns out, doing so can have some unintended consequences. Today we’re going to help you understand this common misconception by answering the question, “Should I close the vents in unused rooms to save energy?”

What’s the idea behind closing vents in unused rooms?

In theory, closing off vents in unused rooms sounds like a great idea. By closing the vents and shutting the doors in rooms that mostly stay unoccupied, the hope is that we won’t waste energy on heating those rooms and that the blocked-off warm air will be used to heat other parts of your home instead. The reality of what happens, however, is quite different.

What actually happens when you close off vents in unused rooms?

Your heating system is designed to operate under a specific pressure load that is measured for your entire home. When any of your vents are closed off, that pressure load is thrown off balance. This creates a scenario where the pressure in your ducts increases and the airflow to your furnace is restricted.

Problems that can be caused by closing vents in unused room

  • Decreased efficiency. It may come as a surprise, but closing off vents in unused rooms can actually have the opposite effect of what you hoped for. For one, the restricted airflow will force your furnace to work harder and consume more energy (similar to what happens when you have a dirty air filter). In addition, the increased pressure in your ducts that is created when you close off the vents to a room can force warm air to leak out of cracks and holes in your ductwork. That means your furnace will waste energy on heating air that doesn’t even end up in your living spaces.
  • Furnace breakdowns. Another problem that arises from restricted airflow is that your furnace runs the risk of overheating. When this happens, your heating system will shut down and you won’t receive warm air in any parts of your home.
  • Comfort problems. When you close off the supply vents to a room, the return registers in that room will pull air from anywhere it can get it. Often times, this means pulling in cold air from outside through leaks around windows or doors, which can make your home colder. In addition, warm air naturally moves to colder spaces. This causes the heated air from the areas surrounding your closed-off room to leak into that space and make the rest of your home cooler.

If you have any questions about whether or not you should close vents in unused rooms, or if you’d like a heating system serviced or installed in your home, contact Jerry Kelly, your St. Louis heating and cooling contractor. We service the entire St. Louis area, including towns like St. Charles, Town and Country and Weldon Spring.

photo credit: jasleen_kaur via photopin cc