Why Your Basement Is Always So Cold—and 10 Expert-Approved Ways to Fix It

Whether you have a finished basement for additional living space or an unfinished basement for storage, it’s likely the coldest room in your home. In the summer, this may be an asset—but getting through the winter with a chilly basement is less than ideal, as it can affect the temperature in your entire home.

Here, we spoke with experts about why basements are so cold, and how you can fix it—from simple DIYs to larger projects. 

Why Do Basements Get So Cold?

The main reason is that basements are built below ground level, and enveloped in soil that's about 50 to 55 degrees Fahrenheight year-round. They're also typically built out of concrete—a naturally porous material that absorbs and retains the cold. 

Add less insulation and drafty rim joists to the equation, and you’ve got a recipe for an ice-cold basement. “Rim joists—the wood frame that attaches to the foundation where it meets the floor above—are major sites for cold air entry, but often ignored by homeowners,” says Scott Eyman, project manager at Eyman Plumbing, Heating, & Air.

How to Keep Your Basement Warm

Looking to make your basement warmer? There are many different things you can try, from budget-friendly quick fixes to larger projects that may require professionals. Here’s how you can warm up your basement—and keep it that way. 

Lay a Rug or Foam Tiles on the Floor

Concrete basement floors radiate cold back up into the space, but an easy way to stop it is to cover the floor. “Interlocking foam floor tiles, a large area rug over a moisture barrier, or even rubber-backed carpet remnants can make the basement feel several degrees warmer,” says Phil Adkins, president of Adkins and Sons.

Use a Portable Space Heater and Draft Snakes

If you have a finished basement that serves as a playroom, TV room, or game room, a few inexpensive additions can make the space warmer and more comfortable.

“Draft snakes can be placed along any doors to the basement, and portable, electric space heaters can be used in rooms that are used frequently,” says Eyman. 

Seal Air Leaks

Sealing up any visible air leaks or gaps around windows or pipes can stop cold air from coming inside. “Weatherstripping, caulk, or foam sealant is a relatively inexpensive DIY project that helps prevent heat loss to keep your basement warmer,” says Elizabeth Shavers, general manager for HVAC and plumbing at Oncourse Home Solutions.

Check the Dryer Vent Damper

Many people keep their washer and dryer in the basement, which likely means the dryer is vented through the basement wall outside.

“These dampers are supposed to close when the dryer isn't running, but they frequently get stuck open from lint buildup or a broken spring,” says Adkins. “A stuck-open dryer vent is essentially a three-inch hole in the wall, pulling cold air straight into the basement around the clock.” If yours is stuck open, clean or replace the damper.  

Insulate Exposed Pipes

Exposed cold water pipes running through the basement are another source of radiant cold—but they’re easy to insulate. “Foam pipe insulation is inexpensive and takes minutes to install," says Adkins.

Run a Humidifier

Your home’s heating system naturally dries the air, making it feel even cooler. Managing humidity levels in your basement can help the air retain heat a bit longer.

“Running a humidifier to help maintain a balanced humidity between 30 and 50 percent helps hold heat more effectively, and makes your basement feel warmer without increasing your thermostat," Shavers says.  

Apply Window Film

Adkins suggests applying heat-shrink window film as a temporary measure to keep the cold out. “The key is creating an airtight seal around the entire frame, not just covering the glass,” he says. “The film's real value is in the dead air pocket it creates between itself and the window.”

Seal the Rim Joists

This is a bigger project, but it’s worth doing for maximum heat retention. In many older homes, the rim joists at the top of the foundation wall sit uninsulated with gaps on the sides, allowing cold air to rush into the basement.

“This is the single most overlooked source of cold air in a basement,” says Adkins. “A can of expanding foam and a few pieces of rigid foam board cut to fit each joist bay can make a dramatic difference. Focus on the corners first, as that's where the largest gaps tend to hide. The full perimeter takes a dedicated afternoon, but delivers one of the highest returns of any fix on this list.”

Insulate the Basement Walls

Adding insulation to the cold concrete walls can go a long way to retaining warm air in the basement. Eyman says that using rigid foam board offers long-term savings on your overall energy costs. “Filling the gap with cut-to-fit foam board plus spray foam is considered one of the best home renovation moves anyone can make,” he says. 

Insulate the Basement Ceiling

Your cold basement could have another unintended consequence—making the living areas above it cooler, too. Adding insulation to the basement ceiling can stop cold basement air from cooling the floors above it and keep the entire house warmer.

“If the basement is unfinished and primarily used for storage or utilities, then insulating the ceiling between the joists keeps the main living space warmer and can noticeably reduce heating costs,” says Adkins. “Friction-fit fiberglass batts work well here and don't require a contractor.”