36,900 BTUH: This is suitable for a 2 to 2.5 car garage or up to 350 square feet. 49,200 BTUH: This is suitable for a 3 to 3.5 car garage or up to 550 square feet. 61,500 BTUH: This is suitable for large garages or up to 750 square feet.
A basic rule of thumb for forced-air heaters is 45,000 Btu to heat a two- to 2-1/2 car garage, and a 60,000 Btu garage heater for a three-car garage. The makers of low-intensity infrared tube heaters say that 30,000 Btu can heat a two to 2-1/2 car garage, and suggest 50,000 for a three-car garage.
For a 2 car garage with 500 sq ft to 700 sq ft, the estimated heater size is 30,000 to 45,000 BTUs. For a 3 car garage with 750 sq ft to 900 sq ft, the estimated heater size is 45,000 to 55,000 BTUs. The height of your ceiling will impact the size of the heating unit you get.
A general rule of thumb is to use 10 watts per square foot for electric heaters, or 45 BTUs per square foot for gas heaters.
Here's a rough guide to determining the BTU requirement based on your garage's size: One-car garage (150-300 sq ft): 6,000 – 9,000 BTUs. Two-car garage (400-600 sq ft): 9,000 – 12,000 BTUs. Three-car garage (600-900 sq ft): 18,000 – 24,000 BTUs.
12,000 BTU – ~550 sq. ft to ~800 sq. ft. 15,000 BTU – ~750 sq.
To heat an average two car garage, you'll need a garage heater that is capable of heating roughly 6,000 - 9,000 cubic feet of air. We recommend getting a 30,000 - 50,000 BTU garage heater to get your two car garage to a comfortable temperature.
The average sized 2 car garage's square footage usually ranges from 400 (20×20), 576(24×24), and 720 (24×30) square feet.
A garage heater that is too large for the space will not heat the space more quickly. A heater that is too large for the room will continue to heat for an extended period of time beyond the temperature set point, wasting energy. We call this a temperature swing.
The most cost-effective method to heat a garage is often through insulation and sealing gaps first, as this reduces the amount of heat required. Once that's done, portable electric heaters have the lowest initial cost outlay.
The Tradesman 1500 provides radiant heat energy, which instantly warms people and solid objects within the beam of heat. It is ideal for patios, balconies, workshop, garage, etc.
Most standard two-car garage sizes are 20×20 feet, 22×22 feet, 24×24 feet, or 28×28 feet.
Open garage windows and doors to let sunlight in. This warms up the space without any cost. Cover windows with clear plastic to keep the warmth inside. Another way is to use the heat from your house.
Since a 20×20 garage is the minimum sized two car garage we recommend, you might think about going larger or higher so you don't crowd yourself out the first day! A 20×20 Garage can hold two smaller cars, but you will have very little extra space around the cars for getting in and out and for storing extra items.
A recommended garage heater size for a one-car garage is about 8,000 to 12,000 BTUs. Keep in mind that smaller spaces heat faster, so you won't need a garage heater with as much power and range as larger garages.
The answer is yes, as long as you choose the right heater and operate it safely. You'll want a space heater that's rated for indoor use and does not require extra ventilation (since garages typically have little airflow).
To heat a 40×60 shop, which is 2400 square feet, you'll typically need between 108,000 and 132,000 BTUs.
Calculating Your Garage Heater Size
Watts are easy enough to follow as they can be quantified by 10 watts per square foot of space. For example, in an area that is 20 feet by 24 feet you would need 4800 watts of power (it's just the total square footage, 480, multiplied by 10).
Site-Built 24×24 Garage Cost: Around $25,000
However, $25,000 is a good entry point for a custom, site-built garage. It is also important to note that while only a site-built garage can make use of the convenience of a concrete floor, that is not included in the $25,000 average price point.
A standard two-and-a-half-car garage is generally 26 feet wide and at least 20 feet deep (26×20). This is a little larger than the usual two-car garage, but smaller than a three-car sized version. The extra space is ideal if you have additional vehicles such as a motorcycle, or for a storage or workshop area.
As a general rule of thumb, a 20 lb propane tank will last for approximately 10-12 hours when used for heating purposes at a rate of 30,000-40,000 BTUs per hour, depending on the heat setting.
Whether you use it in your garage to keep your cars warm or in your shop to keep the work force busy and comfortable, this garage heater transfers almost all of the fuel it burns directly into clean safe radiant heat. Utilizing a unique power pile thermocouple to control the valve, there is no electricity required.
If you have a smaller garage that's well-insulated, then a propane heater or a combustion space heater would work well. If you're looking for a heated garage floor, then infrared heaters are the best option.