Different Types of Garage Heaters (How They Work & Safety)


If you live in a cold climate and spend a lot of time DIY or some work or project in a garage. You may be asking yourself how to keep your garage warm in winter. Let’s look at various kinds of heaters.

Primary heater types are forced air, convection, and radiant. They can be mounted or portable and are powered by electric, natural gas, kerosene, or propane.

Let’s look into the best type of heater for your garage and safety features to look out for.

Types of Garage Heaters

Forced Air Garage Heater

Blasts hot air in cycles into the room. These have different fuel types like natural gas and propane. Very cost-effective to operate because gas is often cheaper than electricity.

Gas-powered units cost more than electric units and often require installation by a licensed professional.

A forced air heater will stir up any particles in your garage. Big problem if you work with wood or paint or coat things. With a forced-air heater, the air is warmer at the ceiling and cooler at your feet.

Convection Garage Heater

Radiators with heating elements to warm the air around the unit. Usually, oil or water-filled. Among the most affordable units. But they take a long time to heat a cold space to a tolerable temperature. Portable and mounted types available.

Radiant Garage Heater

Infrared reflectors direct heat outward for spot heating. Large overhead units will heat the entire garage efficiently. Well suited to DIY.

Offers steady warmth without blowing air to stir up dust or keep dust airborne that can ruin your coating projects. Available in a range of sizes.

Mounted or portable and powered by natural gas, propane, or electricity. Infrared heaters are quiet, but placement in the garage can be critical.

Avoid High-intensity infrared heaters that glow visibly red. Most of them aren’t approved for residential usage.

Infrared heats objects first. Then the air.

Radiant heating systems can also be installed under a floor. Underfloor installation works great with epoxy floors.

Types of Power for Garage Heaters

Electric Garage Heaters

Electrical heaters don’t use open flames and don’t create waste fumes. Hence, they’re safe to use in small spaces—Compact, reliable, and lightweight.

Pulls a lot of power and usually requires a designated electrical circuit and breaker.

Heats areas up to 600 sq. ft.

Natural Gas Garage Heaters

Good option if you already have natural gas serviced to your home. You won’t run out of fuel, as you might with propane or kerosene.

Most economical choice. Requires venting. Highly durable and extremely powerful, but some gas is burned off as waste. Requires maintenance. More powerful than electrical heaters. Lots of heating capacity for medium and large garages.

Heats areas up to 4500 sq. ft.

Propane Garage Heaters

Self-contained heaters connected to propane tanks. Warms heating coils by burning propane gas. Uses an open flame, so poses a higher fire risk. Less efficient than electrical heaters. Generates more heat than the electrical heater.

It can be installed on your home’s propane line and also available in individual tanks.

Some heaters don’t require ventilation. Be sure the one you buy is designed for ventilation-free use if that is your intent.

Heats areas up to 4500 sq. ft.

Kerosene Garage Heaters

It is similar to propane, only harder to get a hold of and not quite as clean of a fuel-type. Also typically more expensive. Filling a kerosene heater is messy and potentially dangerous, Not much reason to take this over propane.

Portable Garage Heaters

Can be moved between workstations. But take up space and are trip/tip-over hazards. Multifuel forced air options works fast to produce heat where needed most.

Credit

Power fans stir up all dust and other particles in your garage. Some models produce fumes of water vapor which makes ventilation necessary.

Portable electric units cost less than multifuel. Available also in radiant heat and convection varieties.

Portable garage heaters are popular. Propane is most common, followed by electric and kerosene. Gas models produce a lot of heat for their size.

Mounted Garage Heaters

Mounted to the wall or ceiling. Wide variety of options, including energy type. Size and price. Almost all models have adjustable thermostats, built-in safety features, and remote control.

Usually cost more than portable types. Frees up floor space, and you don’t need to worry about cords or tripping over a heater.

Some fan-forced heaters come with adjustable louvers that allow you to direct the heat where you want it to go.

Fastest Way to Heat Your Garage

You can use forced air heaters to heat the garage when you need to spend time in the garage.

Combustion space heaters can run multiple types of fuel. But they are very loud and introduce moisture to the air. And fuel odors may bother some people.

Propane has most of the heating power over a short time, and you can grab a cheap propane tank from just about anywhere. Just remember to ventilate your garage.

Combustion heaters produce carbon monoxide. They should never be used without opening your garage door several inches and/or opening windows to create ventilation. They should also never be used inside your home. Even in well-ventilated garages, you should install a carbon monoxide detector for added safety.

How Can I Heat My Garage Cheaply?

Most forced-air units cost half as much as low-intensity infrared tube heaters.

Geothermal systems provide the most efficient type of heating for your whole house. They can cut heating bills by up to 70 percent. Like other types of heat pumps, they are also very safe and environmentally friendly to operate. Can be very expensive to install after initial construction.

If you have very mild winters, Only Insulating your garage can be enough. That is, you are ready to wear some layers while you work. But you won’t have any control over the temperature in your garage.

What Type of Heater Is Best for Garage?

The best garage heater for your space will be the one that produces enough heat for you to comfortably work on your projects without breaking your budget. You have to decide what option works best for you.

What Size Heater Do I Need for My Garage?

It depends on things such as garage size. Climate zone where you live and temperature you feel comfortable to work in.

Gas heaters are typically better suited for larger spaces.

When calculating the size of the heater you need, you first should know the amount of square footage, the height of your ceilings, the insulation level, and the amount of temperature increase from the outside.

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

How Many BTUs Does It Take Heat a Garage?

British thermal units ( BTUs) are how heat output is measured.

But you don’t have to calculate formulas to figure out what size heater you need. Most manufacturers tell you the maximum area in square feet that units adequately heat.

The number is based on garages with 8-foot ceilings. If your ceiling is higher, take that into consideration.

A BTU is energy required to heat a single pound of water by one degree Fahrenheit. This comes out to roughly 1055 joules. One watt equals just under three and a half BTU.

A heater producing 1,000 BTU will heat 1,000 lbs of water by one degree Fahrenheit per hour.

If You Want to Calculate Btus, Here’s the Formula

Insulation * Cubic Feet of Garage * Temperature Rise) / 1.6 = # of BTU

  • Heavy insulation 0.5
  • medium 1.5
  • Light insulation 2.5
  • no insulation 3.5

Area of 3,840 cubic feet, with a 35 degree temperature rise with average insulation (or 1) would come out to this: (1 * 3840 * 35) / 1.6 = 84,000 BTU. To get this down into watts, divide the amount of BTUs by 3.41. At 84,000 BTU, this comes out to approximately 24,633 watts.

Alternative way

1. Take the cubic feet of your garage (length x width x height).

(say 25x25x12 = 7,500 cubic feet)

2. Estimate the coldest outside temperature, and think of your ideal room temperature

(say 30°F and 70°F)

3. Subtract the cold temperature from your goal temperature

(70°F-30°F = 40°F)

4. Multiply that by your cubic feet

(40 x 7,500 = 300,000)

5. Then Multiply by 0.133 (or 0.2394 if you used Celsius)

(300,000 x 0.133 = 40,000 BTU for a 25′ x 25′ garage with a 12′ high ceiling)

Rule of thumb: 1 sq ft = 10 W = 34.1 BTU


Here is a table of common garage sizes and the corresponding garage heater capacity, based on this rule of thumb

Garage SizePower in WattsPower in BTUs
240 sq ft (12×20 1 car garage)2,400 W8,200 BTU
440 sq ft (22×20 2 car garage)4,400 W15,000 BTU
620 sq ft (31×20 3 car garage)6,200 W21,200 BTU
800 sq ft (40×20 4 car garage)8,000 W27,300 BTU
1000 sq ft 10,000 W34,100 BTU
1500 sq ft15,000 W51,200 BTU

Obviously, this is a very rough estimate. To more precisely size a garage heater, you have to consider climate, ceiling height, and insulation as well.

What Is Better Infrared or Blue Flame Heaters?

Both blue flame (propane and natural gas) and infrared heaters are extremely efficient (usually 99 percent), using about the same amount of gas to produce the same amount of overall heat.

Blue flame heaters operate, warming the air in the room.

Infrared heaters use gas or electricity to heat panels that radiate heat outward very targeted way.

Infrared energy is absorbed by the objects with which they come in contact.

What Is Better Gas or Electric Garage Heater?

Gas heating is generally less efficient, but it’s much cheaper than electricity.

Electric heaters are cheaper to buy. Gas heaters leak heat and fumes, but any type of electric heater is 100% efficient. If you don’t want any heat being wasted, go electric.

Propane can be stored safely in a tank on your property, while electricity is subject to power outages.

Do Garage Heaters Use a Lot of Electricity?

Using an electric heater depends on the per kilowatt cost in your region. If your heater has a 1000 watt rating and your electricity cost is $0.15/Kwh, your cost to operate for one hour would be $0.15. Check your electricity bill to see the rate per kilowatt-hour.

Check the power requirements of your current heater or a new one. It’s on the specification label. Power usage is measured in kilowatts—the equivalent of one kilowatt-hour.

Track your daily usage how long your heater is on average. Multiply the hours of use by the heater size, and you get your daily energy cost. Multiple by the estimated number of yearly usage days. You get estimated annual power costs.

Room Sq. Ft.Heater Wattage
50500
100750
1251000
1501250
1751500
2001600
2502000
3002500
350-4003000
450-5004000

Determine Square feet by multiplying room width by room length. 

Look at recommended watts from the chart.

Lots of windows? Exact square footage not listed? Choose the next highest wattage.

Warmer climate? Newer home? Choose the next lowest wattage. 

This is a very rough estimate. To more precisely size a garage heater, you have to consider climate, ceiling height, and insulation as well.

For every million BTUs of heat output, a gas heater will cost you $18, propane is around $30, and an electrical heater will cost about $35. These prices can change due to fluctuations in fuel and energy costs.

How Can I Heat My Garage Without Electricity?

With portable propane, kerosene, or infrared heater.

Some gas heaters may still require electricity to function.

What Type of Heater Is Cheapest to Run?

Gas generally costs less than electricity.

Oil-filled radiators: oil is excellent at holding on to heat, making oil-filled radiators among the most efficient. They’re also one of the cheapest.

Where Should a Heater Be Placed in a Garage?

Usually at the back of the garage facing toward the door. And aimed downwards at a 45-degree angle. Between car bays are suitable too if there are space and clearance.

Can You Heat an Uninsulated Garage?

You can. But in a very cold climate, you will be wasting money.

Insulate your garage walls, doors, and ceiling. The insulation will pay for itself in 2-6 years through lower energy costs.

When the ceiling, walls, and door are insulated, garage heater efficiency goes up 100% or more. Insulation is cheap compared with the cost of electricity, natural gas, liquid propane, and K-1 kerosene.

Infrared heaters are ideal for uninsulated and drafty spaces. They heat objects and not air.

Suppose you can ventilate your garage properly. In that case, a portable propane heater is a good choice for an uninsulated garage.

Oil Filled Heaters

Oil-filled radiators are cheap to run. There is no need to replace or refill the oil. They operate warming the oil inside the unit. These warm the room slow. Oil-based radiators do not produce Carbon monoxide.

What Temperature Should You Keep in a Heated Garage?

45-60 F or 8-15 C. This saves a lot of energy. And keeps your stuff and car form keeping freezing.

If you need to use the garage for a DIY project or work. Raise the temperature to 70 F or 20 C

Humidity should be 45-50%. If it’s higher, you may need to ventilate your garage better. You can also use a de-humidifier or shut off the heating system and open the garage door about 10 inches or 30cm for 15 minutes.

How Much Does It Cost to Heat a Garage?

The average price for an electric garage heater ranges from around $100 to $400. Most units can be installed manually. Be advised that their energy use can boost your electric bill by about $20 to $100 a month. The average price for such an installation can range from about $500 to $2,000.

A natural gas garage heater usually ranges from about $400 to $800. Many heaters come with ventilation equipment, but some companies sell them separately. If that’s the case for your unit, expect to pay about $150 to $300 extra. If you hire a plumbing professional or an HVAC expert. The average price for such an installation can range from about $500 to $2,000.

The cost for a propane gas garage heater usually is around $150 to $450. Still, you might need to pay more if ventilation equipment is sold separately.

For every million BTUs of heat output, a gas heater will cost you $18, propane is around $30, and an electrical heater will cost about $35. These prices can change due to fluctuations in fuel and energy costs.

How to Install Garage Heater

Tools

  • Screwdriver kit
  • Multitool kit
  • Adjustable wrench or wrench set
  • Cordless drill
  • Pipe wrench
  • Plumbers tape
  • Tape measure

Materials

  • Gas lines
  • Gas line connectors
  • Heating unit
  • Vent pipes

Installation

Infrared heaters have to be installed a minimum of 7 ft. above the floor and require clearance of a minimum of 4 inches. from the ceiling (Always check the manufacturer’s instructions and recommendations)

Mount The Heater

Check manufacturer instruction for clearance from the ground and mount with hanging brackets. Check where to put gas, vent, and electrical connections.

Gas pipe size and installation

Size the gas pipe properly, checking the manufacturer’s instruction manual for your gas heater. You have to provide adequate gas pressure to the heating unit. Use proper joint compounds and test for leaks. Check the local building codes also for gas piping. It will likely have to pass inspection before you can operate it in some states and countries.

Electrical Connections and Venting

Pick a place to mount the thermostat. Check manufacturer recommendations. Keep it in an area where it’s exposed to the average temperature. Set up wiring connections by referring to the wiring diagram. Set up proper venting.

If you don’t have expertise with electrical and/or gas systems, hire a professional to safely install your model.

Garage Heater Safety

  • If you suspect a leak, switch off the gas supply at the source when it’s safe to do so. Don’t use lighters or anything else that can produce a spark
  • If you smell gas, oil, or other fumes in your garage, don’t ignite a heater
  • For portable heaters, don’t place them in high-traffic areas. Keep them away from animals and children
  • Don’t place the heater near items that are easily flammable when they get hot
  • Don’t use extension cords with heaters. They are prone to getting hot and causing shorts.
  • Clean the heater periodically to prevent dust and debris from building up and catching fire.
  • Purchase a heater that is suited for indoor purposes
  • Switch off the heater as soon as you’re done using it
  • Heaters that use open flames. Keep flammable liquids or sprays away from them
  • Don’t leave your heater unattended
  • Don’t move the heater while it’s on. Switch it off and wait for it to cool down. Then it’s safe to move it

Look for These Safety Features Found on Most Heaters

  • Tip-over switch: This switch automatically turns the heater off when it’s tipped over or if there is an operational failure
  • Thermostats: A built-in thermostat will switch the heater off if it identifies the oxygen is below a certain level
  • Automatic shutoff in case of high temperatures
  • Cool-touch body: If you accidentally touch the heater, it won’t burn you.

Combustion heaters produce carbon monoxide. They should never be used without cracking your garage door several inches and/or opening windows to create ventilation. They should also never be used inside your home. Even in well-ventilated garages, you should install a carbon monoxide detector for added safety.

A Word of Caution for Woodworkers

Two big things come to mind when it comes to garage safety and heaters: sawdust and flammable vapors. Neither one of these mixes well with heaters.

If you do woodworking, we always recommend checking in with heater manufacturers to see which products can be safely used in your garage.

If you’ll be working on wood projects or using spray finishes, choose a heater with a separate combustion chamber. They burn fresh outside air instead of the dust or paint-laden air inside a garage. There’s a slight fire danger using a conventional heater. The dust and paint particles will cause burner problems that require service calls.

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