How To Heat a Garage Cheaply


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The garage is one of the handyman’s favorite places to hangout. With a plain concrete floor and unfinished walls, it’s a great place to work on dirty or messy projects. Unfortunately, the bare floor, unfinished walls, and lack of HVAC installation means that a garage can be cold in the winter. If you want to spend time working in your garage during winter weather, you need to do something to make the space more comfortable.

How can I heat a garage cheaply?  Heating your garage does not have to be expensive or complicated. Here is what you need to do to raise the temperature and make the garage a great place to work even in winter:

  • Know how much heat you need
  • Insulate first
  • Choose a heat source – electricity, gas, or wood

Know How Much Heat You Need

Start by figuring out the size of the heater you need. If you install a heater that’s too big, you’re wasting money. If you install a heater that’s too small, it will run all the time, and you still won’t be comfortable. Start by calculating your square footage. That’s just the length times the width of your garage. 

To calculate how many BTUs  (BTU is a unit of measurement. The BTU output measures how much heat a given appliance is generating) you need for an insulated garage, take the square footage divide by 200 then multiply by 6000.

For an uninsulated building, also divide the square footage by 200, but then multiply that number by 9000. Calculating the BTUs lets you know what size heater to buy.

If your garage is 400 square feet, you would come up with 18,000 BTU for a garage that lacks insulation.

Seal It Up

One of the most cost-effective things you can do to keep your garage warm is to insulate. Insulation will help you retain the warm air that’s there and keep the cold at bay.

Start by adding weatherstripping around your doors and windows. Add insulation to the walls and ceiling to keep your garage toasty.

Make sure to add insulation to the garage door, and check to make sure it seals against the floor.

Adding insulation to your garage reduces the size of the heater you need by about one third. That reduces both the up-front and ongoing costs of running your heater. The great thing about insulation is that, once it’s installed, it works for free.

There are lots of choices for installing insulation. If your building has open walls, you can hang fiberglass batts or spray the walls and ceiling with expanding foam.

If the walls are sealed, you can still punch small holes and spray foam or loose cellulose insulation into the cavities. Don’t forget to insulate the ceiling or roof – heat escapes from buildings by moving up. 

Be sure to check out my article on insulating garages for more details.

Heating Choices

When it comes to generating heat, there are three basic choices: electricity, gas, and wood. Each has advantages and disadvantages. You should consider factors like ease of installation, the ongoing cost to operate, and permitting requirements before installing a heater.

Electric heaters are the easiest to install and the safest, but the most expensive to operate. Gas heaters are cheap to run but may require professional installation. They can also potentially be unsafe. Wood-burning stoves can be inexpensive to run if you have a steady supply of wood but may require professional installation as well.

Electric Heaters

Electric heaters range from small plug-in space heaters to split ductless heating systems. These systems operate cleanly and pose no safety hazards. One drawback that most electric systems share is a fan – blowing air around a shop can lead to dust particles settling on surfaces that you are finishing.

The most straightforward electric system is the space heater. These little heaters plug into the wall and pump out heat. They are cheap and easy to place, but most are small. It is challenging to get adequate heat for a full garage from a tiny space heater.

Another good choice is an infrared electric heater. These heaters mount on the wall or ceiling of your garage and bathe the garage in infrared rays. These heaters feel like being outside on a warm summer day. Another good point of infrared electric heaters is that they are among the cheapest electric heaters to operate. 

The top of the line in electric heaters is the split ductless heater. These are installed in two parts, an internal air handler, and an external compressor/heat pump. Split ductless heaters will keep your garage toasty warm. They are also the most expensive electric heaters and usually require professional installation. They are great at heating but fail the cheapness test.

Pro tip: make sure your heater isn’t close to any combustibles. Keep wood finishes, fuels, solvents, and other items as far from the heat source as you can. 

Gas Heaters

The cheapest heaters to operate are gas heaters. They can be fueled by natural gas lines that feed your home, or from separate propane tanks. Gas heat is much cheaper than electricity, and the units tend to be less expensive than similar-sized electric heaters. 

Burning gas can produce harmful by-products like carbon monoxide. This gas is clear, odorless, and toxic. Make sure your gas heater has adequate ventilation when you install it.

If you aren’t sure, hire a pro – it’s literally a life and death situation.

The least expensive gas heaters are propane-fueled radiant heaters. These heaters burn propane to create infrared heat. They radiate out the heat like an infrared electric heater.

There are indoor propane heaters available; make sure you read the fine print to set it up safely.

Another fine choice is the forced-air propane heater. These heaters burn propane to heat air, then use a fan to push the air out into the room. They are cheap and straightforward to operate but can be noisy.

Forced-air propane heaters also blow dust around, which can make finishing wood difficult. These heaters may require professional installation to guarantee that they fumes are vented properly; installation can be expensive.

Pro tip: if you install a gas heater, spend another twenty bucks on a carbon monoxide detector. This device can warn you of a potentially lethal situation before any harm comes to you. It’s cheap insurance that can save your life.

Burning Wood

The oldest source of heat is burning wood. People have been using wood fires to stay warm since the time of cavemen. Wood-burning stoves work well if you have a source of timber, but they can get expensive if you must buy logs to feed the fire.

Make sure to check your local regulations before installing a wood stove. They are restricted in some places, or your town might require permits before installing a furnace.

Wood-burning stoves come in a range of prices. The cheapest is just a kit that lets you turn a steel barrel into a stove. The most expensive models cost as much as a used car. 

The biggest drawback to wood-burning stoves is control. Unlike electric or gas heaters that come with a thermostat, wood stoves don’t have an on/off switch.

The garage gets cold when you aren’t there to feed the fire, and the room can get uncomfortably hot if the fire is too big. Still, wood-burning stoves are the only heating method that can potentially work for free.

Pro tip: if you do install a wood-burning stove, keep as much of the stovepipe in the building as you can. The chimney is a source of heat, too; don’t waste the heat for appearance’s sake.

Which Heater to Choose?

Ultimately, heating a garage cheaply is an individual decision. Electric heaters are easy to install but cost the most to operate. Gas heaters take more work to install but heat very economically.

Wood-burning stoves offer the least control over temperatures but can run for free. The garage heater that’s best for you is a matter of your skill level, availability of fuel, and the amount of heat you need to be comfortable. 

Resources

Tony

Hi there, my name is Tony. Having worked in the construction industry for over 30 years and being a weekend warrior on my own home I definitely have plenty of war stories to share. Have a topic or project you are interested in trying? Let me know and we will try to put together an article or video on it!

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