40x40x10 BTU’s needed

[Lizstitches]

I’ve checked many posts here to see if I’m in the ball park
I did find a calculator online that gave me a outrageous number and I’m wondering if it could be true, going to be running nat. Gas
I have a 40 x 40 x 10’ceiling with good insulation r19 I the walls and r38 thruout the ceiling I live in the Buffalo, NY area so it gets cold here in the winter the heater will probably run all winter to keep it at about 50 or so and bump it up occasionally as needed to work out there. From the newair.com website it. Is recommended a 150,000 BTU unit I thought that is way too big, I was thinking something in the 60-80,000 range would suffice, from the feed back I got from friends and neighbors that have heaters of this style

 

[sarman47]

I am currently installing a 80k Big Maxx natural gas heater in my insulated 45x30 Garage with a 12’ ceiling's here in Eastern Ontario.

May be a little on the plus side, but should be fine.

Here is a link from Menards with some suggestions.

https://hw.menardc.com/main/items/media/MRHEA001/Prod_Tech_Spec/6350032_4_POP.pdf

 

[Shop Specialties]

80,000 BTU should work just fine for your application.

 

[Showkey]

Agree 80k should do the trick:

Menards wall chart.......

 

[marinusdees]

I have a 40' x 40' with 12' ceiling, well insulated, but 3 10' x 10' uninsulated garage doors, lots of glass. I keep it at 40 degrees minimum, don't want anything to freeze. Turn it up to 60 when I go in. I have a 150,000 BTU ceiling furnace because it was surplus (thirty some years ago) and the price was right. It may be overkill, but when I go in, it warms up in 10 minutes. Granted our winters are milder than yours. I'd do it the same now. I have had to replace the gas control valve once, cost about $50 on Amazon.
You can find a "garage thermostat" that goes down to 40. Most conventional thermostats have a minimum of 50.

 

[D45]

Honeywell low temp tstat......down to 35°

$25

Works great!!

https://www.honeywellstore.com/stor...eraturegarage-non-programmable-thermostat.htm

 

[strutaeng]

Honeywell low temp tstat......down to 35°

$25

Works great!!

https://www.honeywellstore.com/stor...eraturegarage-non-programmable-thermostat.htm

Yup, I have that thermostat on a detached 25x25 with 45kBtu with only 2 walls insulated. Roof not insulated yet. I added domestic water in the attic for clothes washer, so I set it to lowest setting when it gets down in the teens (rarely down here, but does happen.)

Otherwise it stays off and only turn the heater on if I need to go wrench on something in the garage.

 

[Showkey]

That minimum set of 50* just happens to correspond to the furnace manufacturer’s minimum intake temperature.

Prolonged low intake temperatures void the rust warranty on the furnace parts like the heat exchanger.

 

[Lizstitches]

Looks like 80,000 BTU’s it is, thanks for the advice

 

[toyotadriver]

Since you plan to keep it a steady temp and bump it up when you work out there, the 80k should do it. If you planned to let it cool down between uses, then I’d recommend something larger since it takes more BTUs to heat up a cold soaked building and its contents.

 

[yeldogt]

With a well insulated shop and cheap NG -- you will keep it above 50. I have propane and keep mine in the low 60's .. 1700sf. My unit is a net of 38k BTU in PA. The savings from 50-60 are nothing.

 

[Milzo]

if your heating it full time 60k, for occasional use 75k