Help sizing LP heater

[JOHN39]

I am looking for some advice on sizing a propane garage heater.
My garage is 26x26 with 12’ walls, walls are 2x6 and will be insulated with R-19. I’m located in Massachusetts close to Boston. My plan is to heat the garage full time to roughly 55-60 degrees.

I have been looking at the Modine Hot dawg heaters but am open to other options. If I go with a modine I was leaning towards a 45k btu possibly a 60k btu. Any opinions on what size would be best for my situation?

 

[MrFreeze]

I have a 60,000 Btu/hr Reznor in my 32 x 48 shop with 13 ft ceilings. I'm in the Pacific Northwest, so probably not seeing temps as cold as you would, but it will heat my shop from 42F to 60F in about 15 minutes when it is below freezing outside. Just a data point for your consideration.

Good luck,
MrFreeze

 

[The Cobbler]

my 400+ garage with 10' walls and similar insinuation does fine on the Modine 30k BTU. I'm sure the 45 will do you fine, but it might be a tad slow on rise if you wanted to bump the heat up any significant amount.

 

[PoorUB]

I looked at the weather in that area and average winter temp, daily low is +20F.

I did HVAC service and install for years. I would stick a 30,000 BTU heater in there and not even think about it being large enough.

I would not install a 45,000 BTU, too large, the 30,000 is probably too large!

I heat my 24x38, poorly insulated garage in North Dakota with 45,000 BTU. Granted, it has only 9 foot side walls, but it easily heats it. I have a buddy with a poor to average insulated garage, 24x32 and he heats his with 17,000 BTU. Keep in mind we get -20F in January, and maybe colder.

I would recommend a ceiling fan to stir the air.

 

[theoldwizard1]

Any non-vented propane heater will put a large amount of moisture in the air. If you are running it full time, your walls will sweat !

Time to investigate a mini-split heat pump. Probably a lot cheaper to operate compared to LP.

 

[Jackfre]

Are you installing this yourself? A Rinnai EX-38 is the best option for LP heat in this application. Yes it is more costly than the hanging heaters, but quiet and cool to the touch. Built in programmable stat. It is well known by LP techs in the region. I know that because I trained most of them over my 25 yrs there.
TOW1 has you on a good track as well. There are rebates on the HP’s and they perform well in MA. The real advantage of the HP in MA is the summer operation. It will cool and control the humidity. Used to drive me crazy that once morning in the spring when the dew point would get hit and I open my tool box to find condensation on my tools.

 

[PCustoms]

Any non-vented propane heater will put a large amount of moisture in the air. If you are running it full time, your walls will sweat !

Who said anything about non-vented?

 

[JOHN39]

My plan was to have the heater vented. I will not be installing this myself, a plumber I know will be doing the install. I haven’t given much thought to a HP, are they able to get the heat back up fairly quickly if the garage was opened or I wanted to bump up the heat? Not sure cost wise what is more affordable to run, electric in my area isn’t cheap.
What size HP would be adequate for this space?
Thanks