Most homeowners think about turning their basements into cozy bedrooms, family rooms, or entertainment centers. After all, basements contain hundreds of square feet of space. Many of them also think, “It’s cold down there. How can I make my basement warmer?”
Many people don’t utilize finished basements because they are cold and feel clammy. Spending a bunch of money and time turning your basement into a comfortable usable space only makes sense if you can make, and keep it warm.
Why Basements are So Cold
Average soil temperatures are 55 degrees F. But that varies with the time of year and location. The R-value of an 8” concrete wall is 1.35, meaning that the inside is about the same temperature as the outside.
All that concrete is a huge thermal mass. It takes a lot of heat to change the temperature. Not to mention the soil temperature. Where I live, we get frost down to 4 feet in winter, and it takes 69 days for the soil temperature to recover after the frost is gone.
Basements are also cool because:
- Warm air rises.
- HVAC vents in the ceiling prevent warm air from circulating to the floor.
- Uninsulated dryer vents, ducting, and pipes that extend to the exterior. Metal is a great conductor of heat and cold.
- Uninsulated rim joist.
- Old windows.
How to Keep a Basement Warm
Basements you have already finished restrict your heating options. Unless you are planning wall and ceiling removal and additional insulation, you can only improve what you have. Using a combination of the following suggestions will help make your basement cozier.
Some of these suggestions are inexpensive, while windows and stoves are pricier but more efficient.
Space heaters are quick, easy, quiet, and inexpensive. They will not heat the entire basement, but most keep an enclosed room (under 200 square feet) toasty warm for less than $50.00.
Most space heaters have timers and safety features to prevent fires. Even so, do not leave your heater on and unattended. Warm is good. Fire, not so much.
Baseboard heaters operate similarly to space heaters. They are long, low, and sleek–without taking up much space. You can purchase plug-in units or hard-wired units. A little more expensive than space heaters, they are available in multiple sizes–up to 84”–for comfort in various-sized rooms.
To heat a room comfortably, you need approximately 10 watts of power per square foot of area. A 1500-watt unit will heat 150 square feet. A 9000-watt and 50-amp heater will keep a 900-square-foot room warm.
Note: Larger baseboard heaters are power hogs. Make sure you understand how much power you may end up using.
Wall heaters are related to both space heaters and baseboard heaters. They hang on the wall and operate without fans. Most are very slim, sleek, and non-invasive.
Wall heaters are cool to the touch and come with many safety features. The unit pictured below heats a room for as little as $0.04 cents per hour. Some wall heaters draw so little power you can plug multiple units into one circuit.
Carpet and Radiant Floor Heaters
Even if you have flooring such as laminate over your concrete floor, it will likely still be cold. Thick heavy area rugs with good underlayment help to keep your feet warm. You may want to tape down your area rugs to prevent movement.
For extra warmth–not only for your feet–but to add heat to the entire room, add a radiant floor heating mat under the carpet. Available in multiple sizes, these mats are one of the more expensive heating options. Hot air rises, so having a warm floor means having a warm room. They are very safe and thermostatically controlled.
You should not install radiant floor heaters directly onto the concrete floor because you will lose half your heat. Make sure you have something with an insulating value between the mat and the concrete. Almost anything that will not conduct heat works, such as another carpet, underlayment, jigsaw puzzle exercise mat, laminate, etc.
Wood or Pellet Stoves
A wood-burning stove and a cheap source of fuel are an energy-saving alternative. Although heating with wood can be a little messy with ashes and wood chips, it provides the greatest heat source (in my opinion). Get a glass-fronted stove, and you can watch the flames.
Another option is a pellet stove. You will have to buy fuel, and the unit requires electricity, but these stoves also provide all-around comfortable heat. Depending on size, pellet, and wood stoves can heat 2000 square feet or more.
Pellet and wood-burning stoves are excellent choices for an open-concept basement. Although the heat will travel throughout even if your basement isn’t an open concept. They will also add warmth to the main floor, saving you more on energy costs. Expect to pay $2,000.00 – $5.000.00 plus the cost of a chimney and installation.
Not only does warm air rise, but it also hovers against the ceiling. Installing a reversible ceiling fan that circulates the warm air ensures uniform temperatures throughout the room. Moving the air around saves energy because you require less heating.
To get the full benefits of the fan, it needs to circulate clockwise–pulling air towards the ceiling and circulating it down the walls. You can find a good remote control fan for around $100.00.
An old single-glazed basement window has an average R-value of 0.91. A dual-glazed window with Low E coating is around R-3.13–almost three and a half times better. Warmer air is closer to the ceiling where your windows are.
Replacing basement windows is one of the best ways to retain heat. Most of the time, you can accomplish the job without disturbing interior walls or finishing. A good installation crew can even cut the wall and install egress windows without causing too much damage.
ndows are always a weak spot in the building envelope. Standard 6” walls have an R-value of 20. The windows are 3.13.