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Can a Space Heater Heat a Garage?

Whether you use your garage as a workshop, a home gym, or as a place to store your household belongings, installing a space heater is a great way to enhance the comfort of your garage, but the ability to heat the entire area will depend on how big space is and the type of space heater you invest in.

A quality heater can easily warm a garage of any size, assuming the heater’s power capacity is optimal for the square footage of the space, it complements the garage’s insulation. It is affixed in an ideal location to thoroughly circulate warmth throughout the entire room.  

We will explore further your garage’s characteristics that make it cold, how space heaters work to circulate heat, and what type of space heater is right for your garage based on a few factors.

Reasons Your Garage Always Feels Cold

Garages feel colder when temperatures drop because they typically lack insulation to retain warmth, unlike the rest of your home.

Most garages are simply designed as extensions of your home for basic storage and vehicle parking, but not suitable living spaces. For this reason, garages are often constructed using concrete because of its durability and building practicality. However, its porosity means that if no heat is present, it will continue to retain cold air from the outside. When heat is present, concrete has a high thermal mass that can keep a room warm for several hours.

This is where the use of a high-quality space heater comes into play and can benefit a well-insulated garage.

Consideration #1: A Space Heater Can Only Heat So Much

It might seem simple enough to purchase a space heater outright and place it in your garage. However, this likely won’t return the warmth retention that you want because you have a lot of space to heat and only a small heater, so you’ll have to keep the device on for long hours to feel the warmth at all.

Space heaters are designed to heat a specific room size, so attempting to heat anything larger goes well beyond the capacity of the space heater itself and could result in less efficiency, more energy used, and little outcome.

To maximize the use of a space heater in your garage, you’ll need to account for your garage’s area and utilize a high-quality space heater that is designed to heat larger areas, not include desk heaters or personal heaters. 

Consideration #2: Your Garage Isn’t Designed To Be Heated

Garages are built-in simplistic forms and with materials that focus on strength and structural integrity rather than comfort or temperature management.

Just because your garage wasn’t designed to be heated doesn’t mean it can’t be. To increase the longevity and efficiency of your space heater so it can distribute warm air throughout the entire garage, you should take practical steps to secure your garage by filling or sealing off any crevices where warm air can get out or cool air can get in.

The metals used for garage doors can also provoke more frigid conditions inside since the doors themselves are not insulated. 

Thus, you wouldn’t roll down your car window when the heating is on for the same reason. Your garage requires the same level of protection to retain the heat more efficiently. Doing so will encourage your garage to hold the heat for longer, meaning you won’t have to rely on keeping the heater constantly switched on to feel the warmth.

DIY Ways To Insulate Your Garage

You don’t need to spend a fortune to have your garage insulated, as there are other ways you can increase heat retention internally with a few simple DIY tricks.

To start, it is recommended that you seal off any drafts where cold air can seep through. This includes your window frames or door frames, as well as any cracks or crevices present between your garage door and the garage flooring. You can easily purchase weather seals and strips that can be measured to cover any air drafts internally. 

White Weather Stripping 50 Feet, 1/4 Inch Wide X 1/8 Inch Thick, Window Seal High Density Foam Sealing Strip Adhesive Foam Gasket Tape for Door Insulation, 16.5 Ft x 3 Rolls Each

Once completed, you’ll then want to use some textiles throughout your garage, as they help trap and retain heat within their fibers, keeping the space warmer for longer. You can consider curtains, low-pile rugs, or rubber garage mats, depending on your garage’s needs.

Insulating your garage isn’t complete until you’ve insulated the garage door as well. The metals used to create your garage door work to protect your home’s exterior more than they do to manage the temperatures inside of your garage. For this project, you can opt for a garage door insulation kit to make the job easier and more budget-friendly.

Reach Barrier 3009 Garage Door Insulation Kit

If DIY projects aren’t for you, you may feel more confident in enlisting the services of a licensed insulation contractor to install insulation for you. Some of the most common types of insulation include fiberglass, cellulose, rigid foam, and spray foam insulation.

How To Choose the Correct Space Heater

Once you’ve taken steps to insulate your garage, you’ve then set up your area for success and can move on to choosing the correct space heater. Don’t look at purchasing just any space heater, as you’ll need one that’s capable of emitting enough heat at a distance that covers a decent portion of your garage. If your garage is larger, purchasing more than one heater to situate on opposite sides of the garage is suitable as well.

Sizing Formula

To further determine the size and power of a space heater, experts calculate approximately 10 watts of power per square foot of your garage. So, if you have a total area of 120-square-feet, but you only anticipate about half of that space for personal use, then a 600-watt space heater could be sufficient enough to keep you warm. 

Now, if you plan on using the whole 120-square-foot area, then you’ll want to size up and purchase a 1,200-watt space heater or two smaller 600-watt heaters that work together to equal the same power capacity.

If your garage already has insulation or you’ve recently installed some, the formula will be slightly different in calculating what power level of space heater you need. 


The location of your space heater will also determine the level of output it offers to your garage. Keep in mind that you should locate your space heater away from flammable objects, liquids, sprays, and fabrics, and you should never place anything on top of or in front of your space heater for safety purposes. 

Both mounted, and portable space heaters provide a range of coverage the heater can reach. Direct, close exposure to the heater may leave you feeling uncomfortable or that the heat is too localized, while the rest of your garage is still cold. Placing a space heater at a safe distance will ensure you receive comfortable levels of warmth and that your heater isn’t at risk for potential fire hazards. 

Heating, cooling, and air conditioning expert Richard Tretheway suggests angling your space heater for a wider aperture and more heat coverage.


When deciding how to heat your garage efficiently, ensure that the space heater you choose is optimized to fit the space of your garage, keep in mind these two things:

  • How you plan to insulate your garage further and;
  • What size and power level of space heater you should purchase

Space heaters can deliver an excellent supply of heating to any garage space, as long as the heater is in the right size and emits the correct wattage in the area. Calculating your space’s needs, investing in a high-quality space heater, and maximizing your garage’s heat-retention, are all ways to ensure that your garage is safely and efficiently heated for long-term comfort.


  • Chris Hewitt

    Chris is a Texas-based freelance writer who loves the outdoors and working in his garage. When he's not enjoying the Texas sun, he can be found tinkering with all sorts of things in his workshop.

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