Garage heater sizing

[spencerb]

Hello,
I am looking to install a heater in my garage this winter. I have a 28x35 attached garage that will be insulated with fiberglass r-19 in the walls (2x6) and R38 in the ceiling. My walls are approximately 9' to the top plate and the ceiling is vaulted 13' at the peak. I have a 16x8 & 10x8 overhead doors, 5 5x3 windows, 1 6' slider and 1 3' man door.

I did a heat loss calc at https://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm

Came up with design loss of 20K BTU per year. I am located in the northeast/Buffalo NY.

I was planning on a getting a separated combustion hot dawg unit just for the added safety. I just dont want to undersize the unit, will probably keep the garage around 68 degrees as I plan to have my dog in it the majority of the winter.

Before I did the heat loss calc I was thinking about a 75K unit, just off what I read for a large garage. Not sure if I should just go with the small 45K unit, or should I size up to a 60K BTU ? The price difference isnt much between the sizes. Just trying to find the proper unit.

 

[spencerb]

It will be a natural gas heater, have a line plumbed to the garage.

 

[Bert_]

I didn't do any math but 45k btu will be more than enough.

I heat my 1000 sqft garage with a 70,000btu heater. The garage has a ceiling and the walls are lined but there is no insulation. I can warm it up to 60* in all but below 0* weather.

 

[pvanderlugt]

i have a 60000 btu Reznor in my 1000 ft2 , 13 ft ceiling shop, here in NW Ohio, and it keeps up fine... no problem with recovery after opening a door and bringing a cold car in...we have similar doors/windows/insulation....I heat all winter, use about 250-300 gallon of propane a season....

Now I am working on cooling it in the summer as well....
Pete

 

[Showkey]

Same here........1000 sqft well insulated similar climate as OP.........had a 60k died after 20 years of unknown service or use. Replaced with 45k btu.........works fine.

The wall charts say similar on sizing and the real choices in available sizes are 40-50k and 75-80k.

 

[D45]

Sounds well insulated.

A 45k will be good

A 60k will just heat up the space faster

Will it be heated all winter or just turned on when you're out there working?

 

[spencerb]

I’m going to heat all winter.

 

[outlander800]

I have a 24x40 on Grand Island so were in the same area. I have 2 man doors and a 16ft garage door, R13 in walls and R19 in the ceiling, no windows. I went with a 45k Reznor unit that I just purchased this spring so I haven't run it yet. I feel it will be just fine.

 

[spencerb]

Where did you buy the reznor? Online or local?