Garage Heater – Recommendations?

[Ron H]

My old Lennox LF24 furnace has been reliable for over 15 years; but the past couple has been throwing one part after the other in it to keep limping along. Repair parts now far as I know could be necessary, would cost over 600 bucks. Seems dumb to toss that kind of cash w/o getting a new one.

Friend of mine has an electric heater (220V) he says does fine and says I should get one of those. Before I make a buy, thought I’d ask what some of you may suggest. My garage is fairly well insulated (could be better and need to work on that) it’s 3 car garage. I keep the temp around 40 deg in the winter when I’m not working in the garage.

Thanks for any recommendations you may have.

 

[toolmanmike]

My old Lennox LF24 furnace has been reliable for over 15 years; but the past couple has been throwing one part after the other in it to keep limping along. Repair parts now far as I know could be necessary, would cost over 600 bucks. Seems dumb to toss that kind of cash w/o getting a new one.

Friend of mine has an electric heater (220V) he says does fine and says I should get one of those. Before I make a buy, thought I’d ask what some of you may suggest. My garage is fairly well insulated (could be better and need to work on that) it’s 3 car garage. I keep the temp around 40 deg in the winter when I’m not working in the garage.

Thanks for any recommendations you may have.

Low ceilings? Is the 220 volt electric you are talking about radiant or forced air (like an electric furnace) 3 stalls would be next to impossible to heat with a radiant heater unless it spans the hole work area.

 

[Fran Blacker]

I'd get spec's on how much electricity any any unit you buy. Calculate how much electricity will cost you. If you want to get fancy a heat pump.

 

[toolmanmike]

Do a simple Manual J calculation to see about how many BTU's you may need. A true Manual J takes many more things into consideration but this simple calc should work for a garage. It will give you a ballpark number. Heat systems can be slightly bigger than requirements and still work fine. With AC you have to be careful. More is not better.

5. Calculate the HVAC load​

Find the total HVAC load by plugging your measurements into the Manual J calculation. The formula for the Manual J calculation requires separate functions, which might look like this:

• (House surface in square feet) x (height of the ceiling)
• (Number of occupants) x 100 BTU
• (Number of exterior doors) x 1,000 BTU
• (Number of windows) x 1,000 BTU

After performing these calculations to determine square footage and total BTU, you can add your solutions together to determine the HVAC load. For example, if a house is 2,000 square feet with ceilings that are 10 feet high and has six occupants, 12 windows and three doors, the Manual J calculation can look like this:

2,000 x 10 = 20,000

6 x 100 BTU = 600 BTU

12 x 1,000 BTU = 12,000 BTU

3 x 1,000 BTU = 3,000 BTU

20,000 + 600 + 12,000 + 3,000 = 35,600 BTU

In this example, the HVAC load for the home is 35,600 BTU, which would call for an HVAC unit of 2.97 tons.

 

[WileERobby]

Depends. Cost = Natural Gas vs. electric supply. Cost = initial equipment outlay vs. years use expectancy. Type of equipment = How much volume to be heated, BTU's required. Constant use, or intermittent use. A lot of factors to be considered overall.

 

[Ron H]

Low ceilings? Is the 220 volt electric you are talking about radiant or forced air

9-foot drywall ceiling, el heater my friend has is forced air.

 

[hunt2elk]

No way I would install an electric heater in my shop. Stick with gas, it will be far cheaper in the long run.

 

[WileERobby]

What system do you have now ? I'd go NG especially if you have the feed already.

 

[Jeff Peterson]

This works great in my 30x30, 9.5 ceiling
A few years back we had a record low of -33 and it still cycled like normal when even the house furnace was struggling

 

[Mackman]

Electric anything would be my last choice.

 

[RemCharger]

No way I would install an electric heater in my shop. Stick with gas, it will be far cheaper in the long run.

In Sask it's crazy to use an electric.. but one province over Manitoba, nobody uses NG.

 

[toolmanmike]

This works great in my 30x30, 9.5 ceiling
A few years back we had a record low of -33 and it still cycled like normal when even the house furnace was struggling View attachment 1525792View attachment 1525793

As it should 37,000+ is pretty big

 

[toolmanmike]

Do a simple Manual J calculation to see about how many BTU's you may need. A true Manual J takes many more things into consideration but this simple calc should work for a garage. It will give you a ballpark number. Heat systems can be slightly bigger than requirements and still work fine. With AC you have to be careful. More is not better.

5. Calculate the HVAC load​

Find the total HVAC load by plugging your measurements into the Manual J calculation. The formula for the Manual J calculation requires separate functions, which might look like this:

• (House surface in square feet) x (height of the ceiling)
• (Number of occupants) x 100 BTU
• (Number of exterior doors) x 1,000 BTU
• (Number of windows) x 1,000 BTU

After performing these calculations to determine square footage and total BTU, you can add your solutions together to determine the HVAC load. For example, if a house is 2,000 square feet with ceilings that are 10 feet high and has six occupants, 12 windows and three doors, the Manual J calculation can look like this:

2,000 x 10 = 20,000

6 x 100 BTU = 600 BTU

12 x 1,000 BTU = 12,000 BTU

3 x 1,000 BTU = 3,000 BTU

20,000 + 600 + 12,000 + 3,000 = 35,600 BTU

In this example, the HVAC load for the home is 35,600 BTU, which would call for an HVAC unit of 2.97 tons.

The only thing the calculation doesn't take into consideration is garage doors. Those make a huge difference in heat loss.

 

[#41]

Heat pumps don't work that well when it is super cold or super hot. On top of that, if your plan would be to keep the shop at 40 still, heat pumps don't like that. 60 degree minimum is what I have been told several times, including my neighbor's son-in-law who runs his own small HVAC company.

Weather a 220V electric heater will work for you depends on how big of a heater, if you can handle the max amp draw, and how "fairly well insulated" your garage is. I have a mix 50amp 220v heater in my 3-car pole building and it is insufficient to make it warm, just enough to make it ok to work in during cold snaps. Insulation is only R19 (doors are also insulated). If it's 30 degrees outside, the heater struggles to keep it at 50, and I have to let it get a head start because it takes a long time to get it up there. The thing about a 220V resistance heater is that it is very inefficient compared to say a heat pump.

Personally, I would go with a heat pump mini, keep the temp at 60 min all the time, and then you will also have AC for the summer.

 

[Ron H]

What system do you have now ? I'd go NG especially if you have the feed already.

Lennox NG LF24 model, was thinking about the same thing since I had gone through all the work to hang, pipe, and vent it back when..

 

[Ron H]

The only thing the calculation doesn't take into consideration is garage doors. Those make a huge difference in heat loss.

Yep, I have insulated doors, but along the top is where I find a lot of outside air blowing in. Had thought about some sort of rubber or vinyl flap overhang there that would bend when opening/closing the doors..

 

[5.7 hemi]

How about a mini split ac system? I’m looking at that for my shop 22x25x12. It’ll be 25000 btu’s and the plus side is that it’s a heat pump style. You can find them for $1500 on up.

 

[Ron H]

How about a mini split ac system? I’m looking at that for my shop 22x25x12. It’ll be 25000 btu’s and the plus side is that it’s a heat pump style. You can find them for $1500 on up.

I’m in da nort country; AC would sure be nice on some hot days; but far fewer of them than bone chilling ones of winter in my parts.

 

[toolmanmike]

I’m in da nort country; AC would sure be nice on some hot days; but far fewer of them than bone chilling ones of winter in my parts.

I was thinking of a mini split system but like mentioned before, they are only efficient down to 25-30°f. Not good for heat in Wisconsin in the middle of the winter.

 

[WileERobby]

Lennox NG LF24 model, was thinking about the same thing since I had gone through all the work to hang, pipe, and vent it back when..

View attachment 1525800

Probably your most cost-effective, and least-work solution would be to repair, or replace, the existing unit. As long as it suits your needs, and it results in the least cost/time/labor outlay, my opinion that's your best bet. Good luck with your resolution !