Updated on 03.14.07

Five Minute Finances #11: Open All Your Vents In The Winter

Trent Hamm

Five Minute FinancesFive Minute Finances is a series of tips on how you can save significant money or reorganize your financial life in just five minutes. These tips appear Monday, Wednesday, and Friday on The Simple Dollar.

This is a tip that my parents discovered the hard way after I moved out, and it simply works. When I first moved out, my parents stopped heating the upstairs of the house because there was no one using the bedrooms upstairs. They simply went upstairs and closed up all of the vents without thinking too much about it. It makes sense, right? You’re just paying extra for the furnace to blow heat into rooms that aren’t being used.


They didn’t notice the problem the first winter because it was viciously cold; the bill was quite high, anyway, and they blamed it on the frigid temperatures.

The second winter, though, they expected to have nice low bills – and they weren’t so low. In fact, their average bill was roughly $30 higher a month than they expected. Why? It turns out that their gas usage in the furnace was higher than two winters previous, even though the outside temperature was warmer.

How is that possible? First of all, the furnace in their home was designed to blow hot air into every room in the house. By shutting off the vents, they were wasting a lot of hot air that was simply just circulating around and eventually coming out of the other vents.

Second, and more importantly, the cold air upstairs was draining the heat downstairs. Heat rises, and thus the heat from the first floor would seep up into the cold second floor through the stairwell and even directly through the ceiling to a degree. This same principle is true even in a one-story home if you have some rooms that you’re not heating – you’re often losing heat if one room is significantly colder than the rest.

In the summer, for their central air, it didn’t matter nearly as much because, again, the upstairs would be hot and they wanted only cool air. However, in the winter, they are much better off with the vents open than with them closed.

If you have closed vents in your house during the winter, open them up, especially if you have multiple stories in your home.

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  1. Brandon says:

    Could this also be because your parents have cold air returns in the house?

    Instead of pulling warm air from the house to heat again, it is pulling unheated air from those rooms and trying to heat it to the right temp?

    While getting bids for our old house, this comment came up when we said we were not going to heat certain areas of the house to save money.

    Take care!

  2. Dave says:

    Strangely enough I follow what your folks do, but take it a step farther. Currently living in an old 3 story townhome. Thermostat is on the middle floor and master bedroom is on the 3rd. If I was to open up the vents on the 1st as well as keep that door open the temperature difference btwn 2nd and 3rd jumps about 15 degrees. By closing of the lower part of the house (which I don’t use as much as I could admittedly) the temp difference btwn 2nd and 3rd is only 5-10 degrees. I’ve not considered what that does to the energy bill, admittedly. I’m more concerned about sleeping through the night.

  3. akl168 says:

    …and don’t forget to change the air filter in your furnance.

  4. Daisy says:

    I can attest to this one. We have electric baseboard heat, not a furnace, but it works out the same. Last month I decided to try closing doors to the rooms we’re not using and turning the heat off in those rooms. Imagine my surprise when the power bill came today and it was increased over last year’s bill at this time (a much colder year, btw) by 15%. Yikes! Wish I’d come across this post a month ago!

  5. V says:

    This “phenomenon” occurs because by closing off the vents or just the entire rooms a temperature gradient is created. Now the warm air that is circulating in the rest of your house will “want” to go to the colder rooms in order that the temperature in the house will be in equilibrium, thus the colder rooms get a warmer and the parts of the house that you are using and want to be warm are cooled down.

  6. Rosie says:

    would this work the same for air conditioning [cooling?] i find that my ac is colder in my kitchen than my bedroom… so i closed the vent in my kitchen. do you think that will help? or hurt?

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