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How Cold Will An Unheated Basement Get

Whether you use your basement as a bedroom, recreation area, or just to store your unused treadmill, the temperature of this space can be 8-10 degrees different from the rest of the house. A cold basement can really affect what you use the room for and how often you visit it.

Knowing how cold an unheated basement can get is helpful. But knowing why it gets cold and how to make it a little bit warmer turns knowledge into power.

Unheated basement temperatures are not likely to fall below 40-50 °F. The minimum temperature your basement reaches depends on outside temperature, exterior insulation, state of finish, elevation, and heating in the rest of the house.

Basement Temperature Not Likely to Fall Below 40 °F

Although it may not feel like it, your basement is not actually freezing. The Chicago Tribune reported that average basement temperatures will only reach a minimum of 40 °F, and are very unlikely to drop lower than that.

Research into the effects of cold climates on basement temperatures has also been carried out. A Canadian longitudinal study (carried out over 7.5 years) reported basement temperatures dropping to about 15 °C (59 °F) in winter.

The temperature that your basement can reach will depend on a number of factors to be discussed in the next section.

Sometimes, you can use the basement’s chilly environment to your advantage, like converting it into a handy root cellar.

What Influences Basement Temperature?

Outside Temperature

The lower the outside temperatures and ground temperatures drop, the lower the basement temperatures can drop as well. So, a colder climate means a colder basement, and typically, your basement will be colder in winter than in summer.

Exterior Insulation

If your basement has exterior insulation, the thick foundation wall will slow down the rate of temperature change from the outside. So, if it is super hot outside, it will take a long time for that heat to transfer into the basement, which makes it feel colder in relation to current conditions.

This means that in summer, the temperature in the basement will be chillier than the temperature outside.

On the other hand, the air will be slightly warmer than the outside temperature in the winter months, which is not a bad thing.

Finished vs Unfinished Basement

If you have properly insulated your finished basement, you shouldn’t experience temperatures lower than 60 °F. The finished floors and walls will not get as cold as exposed concrete.

There are even some benefits to converting your basement into a bedroom area and the lack of living space in cities is causing more people to look at living in basements entirely.

Your unfinished basement will be colder as there is less of a barrier (little to no insulation) from the outside weather. If your walls or floors are still exposed concrete, the coldness of the concrete will transfer to your basement air and make it quite chilly.


The temperature of your basement can also be influenced by its elevation.

If your basement is above-ground to a certain extent (a walkout basement or a daylight basement), it might feel colder as there will be more windows that could let in a draft through small gaps.

However, the warm sunshine will also be able to get into the room, warming it up.

Your below-ground basement will have smaller windows if any, and will definitely be colder.

Heating in the Rest of the House

The type of heating you have installed in your home will determine how hot or cold your basement feels.

If you have one furnace supplying heat to the entire house, your basement will be a lower temperature than your upstairs rooms. The furnace is usually controlled by one thermostat upstairs.

The windows in the rest of the house will also allow solar heat to enter, making the upper floors much warmer than the windowless (or near-windowless) basement.

Therefore, you will adjust your thermostat to a comfortable temperature that takes into account the warmth from the sun. Your basement then suffers because the heating is at a lower temperature.

On the other hand, if the furnace is located in the basement, it can warm the air even if there are no vents supplying this space.

Moisture Drops the Perceived Temperature

Basements are notoriously damp. When there is moisture in the air, it makes the room feel colder. While this many not affect the actual temperature of the air in the basement, the perceived temperature is arguably more important.

Should Unfinished Basements Be Heated in Winter?

The newly framed basement area of a house. The central heat and air ductwork system is beside the stairs

If you want to limit the pairs of fuzzy socks for your weekly load of laundry, it is definitely best to heat your unfinished basement in winter. Even if you don’t use your basement all that often, this can provide numerous benefits.

If your basement is heated, by the law of science, the warm air will rise up to the rest of the house, keeping you toasty as the floors won’t be so cold.

If your basement is too cold, it could also trigger the onset of mold. This is because when the cold basement walls interact with the warm air, moisture forms. So, if you heat your basement, the walls will remain warmer, thus reducing the chance of mold.

Making sure your basement is ventilated properly also helps to reduce the chance of mold growth

However, if you don’t really use your basement regularly, or just feel that it doesn’t get uncomfortably cold, you can definitely choose to save a buck and leave it as is.

How Can I Keep My Basement Warm in Winter?

  • Seal up any windows. Over time, cold air can seep through the tiny spaces between your windows and the window pane, which can cause a chilly draft to enter your basement. Here is a quick and easy method for sealing your basement window that requires no previous expertise.
  • Choosing the right decor. An easy way to warm up your basement is to add a fuzzy rug, some blankets (if there is a couch/bed down there), and some warm-toned lighting. These quick fixes can help to warm up a cold basement in no time. If your budget allows you can install carpets.
  • Buy a space heater. If you use your basement, adding a small space heater, e.g., GiveBest Portable Electric Space Heater (amazon link), makes the world of difference in winter. Put it on for an hour or so before you want to use your basement so as not to waste electricity.

CCC Comfort Zone Metal 5120 BTU Deluxe Milkhouse Utility Heater with Steel Body CZ798BK,Black

You can read a more extensive list in my article on Practical Ways to Warm-up a Cold Basement.


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