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Garage Heating and Cooling

Post your mechanical questions here. Tips. Trick. Techniques.

Post Fri Sep 09, 2016 11:30 am

Posts: 448
My garage is hot as !@#$. Last night I was dripping sweat just putting a front suspension on. Plus my beer fridge is working overtime. :omg: I'm looking into a wall installed exhaust fan. Any suggestions on models and CFMs and all that bs. Also, around the corner is cold weather and then the garage is cold as !@#$. Ceiling mounted heating units?

For's a tight three car garage.

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Post Fri Sep 09, 2016 2:40 pm
C Class Poster

Posts: 172
what about a whole house fan. I doubt it would have done anything about the humidity yesterday/today but crack the doors and turn that Bad boy on for air flow. PS I know nothing about heating or cooling but my attic fan works good to vent the heat.
whole house fan.png

Post Fri Sep 09, 2016 7:39 pm

Posts: 5
If you are going to heat and want to cool as well, look into a ductless mini split system. Get one that has the heat pump and it will do both. The cost of these units are not as much as you might think and are quite easy to install.

Post Wed Sep 14, 2016 5:52 pm

Posts: 338
Location: Ellington, CT
The ductless splits work good for cooling but if you don't have a good tight garage it will struggle during real cold weather as they loose capacity as the weather gets colder. For heat only, an LP Gas Unit Heater works well. You need to have a decent size tank for reliability during cold weather as small tanks will loose pressure once drained down a bit when it is super cold and the heater will lock out. A 125 Gallon Tank is usually good. Pricing for a 2 car garage? For DIY Guys figure $800 for a Unit Heater and $1,500.00 for a ductless A/C Unit. Obviously more if you need to bring in trades. Myself, I have a hydronic unit heater in my garage that runs off the same boiler and loop that heats the house. It costs just about the same as the LP Gas Heater but is most of the time only a good choice during new construction. The plan is to put a ductless split A/C in this Winter, if and when we slow down a bit. Here is a link below for a popular heater but you can buy locally from FW Webb or other supply houses. As far as ductless splits, stick go to the good ones. There is a lot of garbage out there. Mitsubishi, Sanyo, and Fujitsu are brands we use but Mitsubishi is by far the market leader. Anybody looking for any help in this area PM me your specifics and I'll see if I can head you in the right direction. ... P&addons=y

Post Fri Mar 24, 2017 3:04 pm

Posts: 76
Location: Lowell
This will keep you toasty... doesn't help with the cooling. ... 2252256718

Post Sun Dec 08, 2019 11:32 am
I have an overhaed propane heater in 28 x 28 garage,takes hours to warm things up. Anyone ever tried an overhead electric heater instead? Saw some 42000 btu units that draw about 45 amps on high,thinking of hooking one up to my welder circuit. Couple things make me wonder,chart shows it pulls less amps at 208 than at 240,isnt that backwards? Also dont know if its big enough,anyone tried one? Tired of the propane taking hours to warm things. Here are specs.

features + Benefits
ECO2S electronic controller with a large LED display
Automatic 2-stage heating uses lowest wattage required to effectively heat spaces
Includes a 1- to 9-hour timer and a summer fan-only mode
Constructed of 20-gauge electrogalvanized steel with a rust-inhibiting baked enamel finish
Totally enclosed fan motor for long-lasting performance
Spiral steel fin element produces superior heat transfer
Built-in fan delay
Adjustable louvers direct airflow
Single phase
Key Specs
Item# 58595
Brand King Electrical
Manufacturer's Warranty 5 year limited warranty
Ship Weight 34.0 lbs
Product Type Forced air
Blower Included Yes
Thermostat Included Yes
BTU Output 42,700
Heat Settings 2-stage
Blower (CFM) 825
Volts 240/208
Watts 12,000
Amps 52.0/45.1
Thermal Cutoff Safety Device Yes
Remote Included Yes
Plug Type Required hardwired connection
Dimensions W x D x H (in.) 13 1/2 x 15 x 16 1/2[+] How can we improve these key specs?

Post Sun Dec 08, 2019 12:47 pm

Posts: 120
You'd have to ask PRZJohn as I'm no HVAC expert, but 42,700 btu seems small for that size space. I have a 64,000 gas unit in my 12 x 24 shop that does well with it being insulated, but with the most of the insulation removed (I'm redoing some things and adding on) it takes a while to heat up from stone cold.

Post Mon Dec 09, 2019 7:28 am

Posts: 746
I have a 65k Hot Dawg Propane for my detached Insulated 24x36 garage and it warms up nice. It also doesn't take very long for it to warm up I'm sure the insulation and sheetrock etc helps it warm quickly. I have had it for about 20 years and so far works great.

Post Tue Mar 24, 2020 4:48 pm

Posts: 896
I would leave the math to PRZJOHN. One thing to consider when performing said math is to account for the literal TONS of freezing cold steel and aluminum that's inside the actual space. My barn heats right up with a couple bikes in it, but if it's packed tight it takes a very long time to get those rolling heat sinks warmed up too.
Valves are STILL for toilets!

Post Thu Jul 16, 2020 12:56 am

Posts: 435
After freezing my butt off for too many winters, I bought this last year. ... /202043073 Didn't want to deal with a big plumbing project and an unsightly tank of explosive gas behind my house so went electric. It heats the half of my insulated 3-car garage that I work on bikes in nicely. I put it on about 20 minutes before I go out there and its 'comfortable' but not toasty for a long winter wrenching session. It was easy to install and mounts on the ceiling so out of harm's way. No muss, no fuss, does the job and I didn't really notice any uptick on my electrical bill.
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Post Thu Jul 16, 2020 7:55 am

Posts: 422
Location: Foothills of the Berkshires
I heat my garage the old fashioned way, with a wood stove. Doesn't matter what the temperature is outside, can get the garage nice an toasty and can work out there in a tshirt.

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