Why Is My Basement So Cold

When I first moved into my house, it didn’t matter when in the year it was; my basement always felt cold.

After doing a lot of research, I was able to find out that moisture can make your basement feel cold. A lot of the times the reason your basement could feel cold is that it has a high level of humidity, and without the proper ventilation set up.

Basements can be damp, and when you mix that with humid air, the combination of the two will make things feel cold. One other problem with this is that the humidity and cold will create condensation, which could lead to mildew, mold, and rot.

By not having the proper HVAC ventilation set up in the basement, you won’t be able to combat the cold temperatures correctly.

solar heat gainAnother culprit could be what is called Solar Heat Gain. If you are heating your home with a single furnace, chances are your thermostat is located upstairs on the main floor. During the day, the sun will help provide a little extra solar heat through the windows surrounding your home, resulting in the furnace not having to turn on as often.

When the thermostat turns off, the heat that is in the basement will slowly make it’s way up to the upper floors, while the cold air from the upper levels will make its way into the basement.

There are some other common problems why your basement is cold, and I would like to share with you below what I have learned.

Why It Gets Colder As You Walk Down Into The Basement

The most straightforward way to explain this is that warm air rises, while cold air is denser and sinks to the ground. Cold air will tend to move to the lowest point of the room, or until it has nowhere else to go. Warm air in your home will move up to the highest point in the room.

If you were to get down on your knees in your basement and then begin to crawl up the stairs slowly, you should start to feel a temperature change of warmer air on your face as you get closer to the top.

If you have a heated basement, you might also notice that when you start to walk down the stairs into the basement, you are hit with warm air. The reason for this is because of the heated air being pumped into the basement is rising to the highest point of the room, and in this case, up the stairs.

Should I Heat My Basement in The Winter?

The short answer is yes; you should heat your basement during the winter. Even if you don’t use your basement as a living quarter, there are two key reasons why you should consider to heat it.

#1. Health Reasons – During the winter months when warmer moister air comes in contact with your cold foundation walls, the two will create additional moisture that could turn into mold or mildew.

However, when you heat the basement, you keep those foundation walls from getting too cold, which will reduce the likelihood for mold to grow especially during the winter months.

#2. Save on Energy – Believe it or not but if you heat your basement during the winter, this will ultimately help you save money on heating.

Let me explain; The cold air in your basement will make its way out of your home through ductwork or water lines, which sounds like a good thing but it’s not. This loss of heat will begin to bring in colder air from outside, which makes your basement even colder, and as a result, it will make the rooms upstairs feel colder as well.

Most people would turn the heat up higher to counter this problem. When they do this, they are running the furnace more than they need to, which results in a higher monthly bill.

How Can I Make My Basement Warmer?

A lot of people think if they only insulated their basement walls, and installed a sub-floor to come up off the concrete that this alone will help make their basement warmer. But there is more to it than just that.

By installing additional HVAC vents throughout the ceiling in the basement, this will help distribute more heat. But before you do this, you will need to make sure that your furnace is capable of handling the extra square footage.

You will also need to Install a cold air return at the base of the wall; this will help pull the cold air that hangs out at the bottom of the room and take it back to the furnace where it will get recycled into warm air.

Often people have their cold air return mounted at the ceiling or up close to the ceiling, and by doing this, you are not moving the cold air, only the warm air.

This is how an adequately positioned cold air return vent will help make your basement warmer:

image 1Image #1 (Wrong Setup) – Let’s say you have cold air return mounted near the ceiling like in image #1. When the hot air is coming out of the register from the ceiling, all of the hot air will hang out around the middle of the room and up to the ceiling. Making the lower half of the room colder.

All that the cold air return will be doing is, it will be pulling the warm air out of the room and sending it back to the furnace.

image 2Image #2 (Correct Setup) – Now, by moving the cold air return down towards the bottom of the wall, this will now begin to pull the cold air circling the floor out of the room and back to the furnace, while also sucking the warm air down closer to the bottom of the room.

Here are some other tips to help make your basement warmer:

  • Check windows – Often you might find that the basement windows will have bad drafts. You can fix this by either replacing the windows, sealing cracks or replacing weather stripping or installing a plastic weatherproofing over the window.
  • Seal air leaks – Look around at the wiring and piping that exits your exterior walls and make sure they are sealed nicely. Use regular caulking to seal up small holes and cracks up to 1/4 inch in size. For larger gaps, you are going to want to use a can of spray foam insulation.
  • Crawl space – If you have a crawl space, check and make sure that the door going into the crawl space is sealed correctly. Cold air will tend to leak of crawl spaces from under the door.
  • Space Heater – A space heater is another excellent way to help keep your basement warm if you don’t want to extend your ductwork or if you are unable to extend the ductwork because your furnace is not rated for the additional square footage.

Should I Dehumidify My Basement?

It is recommended that you have a dehumidifier going in your basement at all times. The reason for this is because basements tend to be a damp and cold environment, due to moisture coming up through the foundation, water sources, or from high humidity inside of your home.

When the humidity level rises above 80%, mold and mildew start to grow. It doesn’t matter if you have a finished basement, or not, you should keep the humidity level at or below 50% at all times.

There are tools on the market such as a thermo-hygrometer that will help monitor the humidity levels for you. These tools are relatively inexpensive, and you can pick one up on Amazon for around $15. Click here for the current price.

Average Basement Temperature

The average basement temperate should consistently be between 57 to 60 degrees Fahrenheit.


As you can see, for both your health and your comfort, it is important that you make sure to maintain the proper level of temperature and humidity in your basement.

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