Garage heat options

W

WA1DH

Joined
Dec 16, 2009
Messages
141
Location
Rhode Island
I had a 24'x24' detached garage with 12' ceiling built recently. I have an insulated door insulated the walls and ceiling. Drywall is up and I'm working on finishing the interior walls. Over the past winter I ran a torpedo heater on diesel fuel and a thermostat. Based on several cold temperature runs, my heat loss is 31,000 BTU/hr at our typical coldest temperature (10F).

I want to move away from the torpedo heater and install a more permanent heating solution that doesn't put fumes into the space. I have 100A service to the garage, so a single zone heat pump seemed ideal. I started looking into cold weather heating performance and found that only the 36k BTU Mitsubishi Hyperheat units can produce the needed heat capacity at 10F. These units go for around $8k total, so I may have to rule that out. I'm in RI so electricity is not cheap ($0.35/kWh). I have oil heat and have used a 5 gal can to pull from the house tank to run a generator and the torpedo heater.

I'm considering:
Chinese diesel heaters:
I would need 3 units to produce ~30k BTU/hr. Low entry cost (~$300-400) but not the most reliable choice. I would need to do some fabrication for safe exhaust pass through the wall, setting up a single small tank to draw from, set up a battery/charger to power the units, etc. I would fill off my house oil tank from the 5 gal can I use right now.

Toyotomi Laser wall heater:
A single unit produces 40k BTU/hr and runs in the $2,800-$3,000 range. They have a single connector that brings in combustion air and passes out exhaust gases. No chimney required, and plugs into a 120V outlet. I would need to install a small tank and fill off my 5 gal can.

Mobile home furnace:
60k-80k BTU oil burner options available. Priced around $3k new, but I may be able to find a used unit for less. I would need to install a small tank and either a chimney or power vent.

Indirect fired torpedo heater:
70k BTU/hr and priced around $1,500. It's a torpedo heater that has a vent for the exhaust gases. To run indoors I would need to install a flue to vent, which seems like a clunky solution for what is still essentially a portable heater. I could run it outside and pipe the heat in, but I don't want to have to roll it into the yard and set it up every time I want heat.


I'd like to keep the total install cost at or under $3k if possible. The space won't be heated regularly, but I plan between 8-16 hours a week when I'm working out there. Any other suggestions or experience with these heater options?


Here are my utility costs:

Electric: $0.35/kWh ($103 /1mil btu)
Propane (30 lb tank fill): $4.23/gal ($46 /1 mil btu)
Diesel (heating oil): $2.89/gal ($21 /1mil btu)
 
Just noting for your research, the exhaust on a diesel heater is small and they typically come with exhaust pipes that you can route to an outer wall, you could even route it to an old radiator to increase the efficiency.

You can also convert the diesel heaters to use 110 with some power supplies instead of batteries. Or use batteries and hook to a trickle charger.

 
Last edited:
Are you near a wood supply? A nice wood stove can be fired in the morning and keep the place warm all day. Have to be careful about storing flammables in the garage with this option
 
My garage is not detached, but I want to keep it above freezing in the winter, and have the ability to warm it up so that I can work out there for extended periods. I have an overhead heater in the garage that is a separate zone on my hydronic oil fired heating system. The zone is controlled by a simple Honeywell thermostat. When the garage is unoccupied, I leave it at 45 degrees, and when occupied, I set it to wherever I feel comfortable.

There are insulated water lines that can be directly buried to get the heating water out to the detached garage.
 
My one friend has soap stone wood stove in his garage (and his house). The stone heats up and radiates nicely and evenly He put a couple big fans in ceiling to help circulate that. In his house a blower setup behind it that draws cold air low and shoots it past the stove.

Woodstove.com

My other friend has I think 2 pellet stoves, one on each side of a very large garage so on thermostat feed as needed.
 
k1xv said:
My garage is not detached, but I want to keep it above freezing in the winter, and have the ability to warm it up so that I can work out there for extended periods. I have an overhead heater in the garage that is a separate zone on my hydronic oil fired heating system. The zone is controlled by a simple Honeywell thermostat. When the garage is unoccupied, I leave it at 45 degrees, and when occupied, I set it to wherever I feel comfortable.

There are insulated water lines that can be directly buried to get the heating water out to the detached garage.
Click to expand...
I was thinking like that but my parents and many friends have forced hot air in their houses not water/steam.
 
Although it's below the loss you could buy two so you can be above it as this seems to draw 32 amps. Two of them would deliver 51k btu's. Northern tool is having a blowout sale on heaters with this one getting the biggest discount since it's almost summer. I put in a random Rhode island zip and says $28 to ship two of them which isn't terrible. $14 for one.

Two of them with tax and shipping would be about $170 with the huge discount right now. Sure it uses a lot of power but it won't be used often and the higher energy cost is justifiable because you spent nothing on these compared to what other options cost except diesel which has good economics. I'd cover them up when not in use to keep bugs from getting in them.

You could also just buy 1 and buy a regular 120v space heater so it's almost at 31k btu.

https://www.northerntool.com/products/keebar-7500w-manual-electric-overhead-garage-heater-240v-25-590-btu-model-hs1275-06-5212168?cm_mmc=Google-pla&utm_source=Google_PLA&utm_medium=Heaters & Stoves + Fireplaces > Electric Heaters > Overhead Electric Garage Heaters&utm_campaign=Keebar&utm_content=5212168&ogmap=SHP|PLA|GOOG|STND|c|SITEWIDE|INTRADE|{campaign_name}|{adgroup}||857740797|42214667263&gad_source=1&gclid=Cj0KCQjwy46_BhDOARIsAIvmcwMd7ShrhYystusKIieWfdx2Zrcp_f_6Vfm0NIbbxdTZPVL4M-aGrEAaApGJEALw_wcB&gclsrc=aw.ds
 
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I go to hospital a lot with fire dept /EMS. They have electric overhead radiant units that are crazy the heat they put out. How warm do you want it in there when working? Electric or propane quick and easy. Stoves longer to heat and more work.

One of the heat pump units depending on cost is nice IMO. You would have AC for the summer when you want to work on things and it's 90 and humid.

Get a larger propane tank outside?
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Electric version.
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Modine-AMP090AA1401-Brochure.pdf

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Do you have natural gas or propane available?
If so, a "blue flame" heater would do well. They are inexpensive (around $250 or less) and have thermostat controls. Many models are rated to 30k BTUs.
Should be a good match. The blue-flame heaters are certified for occupied areas; no ventilation required. They can be either floor or wall mounted.

The reason I recommend blue-flame over infrared is that blue-flame are convection devices; they heat the air, and so the whole garage would be warmed if you use a small fan to circulate the air inside. However, infrared only heats by radiation, and so the air does not warm up; only objects in direct LoS will be warmed with infrared heaters.

Examples:
https://www.amazon.com/blue-flame-heater/s?k=blue+flame+heater
 
It will be warmer than 10F inside :)

Even a 1500W electric space heater with a fan should suffice. Just turn it on an hour before you start the work.

If those standard 1500W units aren't good enough, Grainger should have something satisfactory.
 
Whatever you do I recommend a heater that vents to the outdoors. You want to get away from fumes and carbon monoxide. Otherwise you are back to ventless fumes such as your torpedo heater.

I had a Blueray heater in a shop and it was not the best choice but I had a lot of air infiltration so it was not a big deal.

I had another shop with a propane ceiling radiant heater and it did an amazing job but again you have combustion byproducts to deal with.
 
WA1DH said:
I had a 24'x24' detached garage with 12' ceiling built recently. I have an insulated door insulated the walls and ceiling. Drywall is up and I'm working on finishing the interior walls. Over the past winter I ran a torpedo heater on diesel fuel and a thermostat. Based on several cold temperature runs, my heat loss is 31,000 BTU/hr at our typical coldest temperature (10F).

I want to move away from the torpedo heater and install a more permanent heating solution that doesn't put fumes into the space. I have 100A service to the garage, so a single zone heat pump seemed ideal. I started looking into cold weather heating performance and found that only the 36k BTU Mitsubishi Hyperheat units can produce the needed heat capacity at 10F. These units go for around $8k total, so I may have to rule that out. I'm in RI so electricity is not cheap ($0.35/kWh). I have oil heat and have used a 5 gal can to pull from the house tank to run a generator and the torpedo heater.

I'm considering:
Chinese diesel heaters:
I would need 3 units to produce ~30k BTU/hr. Low entry cost (~$300-400) but not the most reliable choice. I would need to do some fabrication for safe exhaust pass through the wall, setting up a single small tank to draw from, set up a battery/charger to power the units, etc. I would fill off my house oil tank from the 5 gal can I use right now.

Toyotomi Laser wall heater:
A single unit produces 40k BTU/hr and runs in the $2,800-$3,000 range. They have a single connector that brings in combustion air and passes out exhaust gases. No chimney required, and plugs into a 120V outlet. I would need to install a small tank and fill off my 5 gal can.

Mobile home furnace:
60k-80k BTU oil burner options available. Priced around $3k new, but I may be able to find a used unit for less. I would need to install a small tank and either a chimney or power vent.

Indirect fired torpedo heater:
70k BTU/hr and priced around $1,500. It's a torpedo heater that has a vent for the exhaust gases. To run indoors I would need to install a flue to vent, which seems like a clunky solution for what is still essentially a portable heater. I could run it outside and pipe the heat in, but I don't want to have to roll it into the yard and set it up every time I want heat.


I'd like to keep the total install cost at or under $3k if possible. The space won't be heated regularly, but I plan between 8-16 hours a week when I'm working out there. Any other suggestions or experience with these heater options?


Here are my utility costs:

Electric: $0.35/kWh ($103 /1mil btu)
Propane (30 lb tank fill): $4.23/gal ($46 /1 mil btu)
Diesel (heating oil): $2.89/gal ($21 /1mil btu)
Click to expand...
Air seal the ceiling and make sure you have a bunch of loose fill insulation up there. A house in your climate zone would require R60 in the ceiling per current code. Air leaks make the interior space feel really cold and are primary cause for heat loss. If you air seal the ceiling and add a bunch of insulation up there you should really cut down on the heat loss which will impact the amount of energy required to heat the space.
 
Following this. I have a similar sized garage that I've been trying to keep above freezing. This winter I ran a lot of $$$ worth of kero through a wick heater and it kinda maintained the temps. If I wanted it warm, I would build a fire in the wood stove.

I will have a spare mobile home oil furnace soon as we're upgrading the house to gas. I was debating on moving the oil tank next to the house and just running that to maintain above freezing temps and supplementing with wood when I want it warm but I really don't want to go through the hassle of counting to deal with an oil furnace. It's expensive, needs constant maintenance and I'm pretty sure the tank is full of water and sludge. And I can't even run cheap heating oil / diesel in it due to being outside.

The biggest reason I haven't done anything is the wood stove. It's cheap (free) to operate because I get wood for free and am having some trees of my own cut down. It just isn't something I can leave unattended beacuse it always needs to be manually fueled. I can't justify spending a lot of money on a heating solution when I have a free one.

I thought about the diesel heaters. I'm not looking to heat the garage, just keep it above freezing when I'm gone. I'd need multiple diesel heaters ... and then that gets me back to where I'm looking at a a cheap / free mobile home furnace and running it on bulk heating oil or diesel as needed.
 
JavierH19 said:
Although it's below the loss you could buy two so you can be above it as this seems to draw 32 amps. Two of them would deliver 51k btu's. Northern tool is having a blowout sale on heaters with this one getting the biggest discount since it's almost summer. I put in a random Rhode island zip and says $28 to ship two of them which isn't terrible. $14 for one.

Two of them with tax and shipping would be about $170 with the huge discount right now. Sure it uses a lot of power but it won't be used often and the higher energy cost is justifiable because you spent nothing on these compared to what other options cost except diesel which has good economics. I'd cover them up when not in use to keep bugs from getting in them.

You could also just buy 1 and buy a regular 120v space heater so it's almost at 31k btu.

https://www.northerntool.com/products/keebar-7500w-manual-electric-overhead-garage-heater-240v-25-590-btu-model-hs1275-06-5212168?cm_mmc=Google-pla&utm_source=Google_PLA&utm_medium=Heaters & Stoves + Fireplaces > Electric Heaters > Overhead Electric Garage Heaters&utm_campaign=Keebar&utm_content=5212168&ogmap=SHP|PLA|GOOG|STND|c|SITEWIDE|INTRADE|{campaign_name}|{adgroup}||857740797|42214667263&gad_source=1&gclid=Cj0KCQjwy46_BhDOARIsAIvmcwMd7ShrhYystusKIieWfdx2Zrcp_f_6Vfm0NIbbxdTZPVL4M-aGrEAaApGJEALw_wcB&gclsrc=aw.ds
Click to expand...
Sold out
 
If I were you I'd get a large enough propane tank to supply a gas overhead unit. It'll do a good job keeping a set temp and easily warm the space up when you want it warmer. Do not go electric...it'll cost you an arm and a leg at those temps and your rates are high.
 
tbm5690 said:
If I were you I'd get a large enough propane tank to supply a gas overhead unit. It'll do a good job keeping a set temp and easily warm the space up when you want it warmer. Do not go electric...it'll cost you an arm and a leg at those temps and your rates are high.
Click to expand...
Propane isn't far behind electric on cost
 
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