Reznor BTU's Available?

[tod]

Hey Guys,

I'm considering having a contractor install a Reznor 100,000 btu UDAP ceiling hung propane heater in my pole barn. But, I'm not sure if I should go bigger (in BTU's) or not. Contractor and on-line calculators say 100,000 btu's should work. I'm in Michigan and plan on keeping barn heated at about 40 degrees during the winter when not in use. Then, when I'm out there cranking the thermostat up to about 65 degrees when I go out to work. This barn is just for my pleasure and is not a business.

Specifications of barn:
Size: 30x60x12 ft ceiling
Poured Cement floor
OSB on walls and ceiling
well insulated ceiling and walls
No windows
two garage doors insulated

So, calculators indicate between 86,400 btu's and 108,000 btu's dependent upon insulation factor.

Does Reznor make a 110,000 btu heater? I can't find it anywhere on their website. Or, is 100,000 sufficient for my application. I fear the heater will be too small and I'll regret it later.

Thanks
Tod

 

[2011laramie]

Id say anything in a 75-100btu would be fine even.

I just watched my garage all winter and it barely used 10 btu/sq ft on the coldest alberta winter.

 

[jim7]

Have a pole barn about your size 30 x 64 10 foot ceilings all insulated metal walls and ceiling 1 garage 1 service door door 4 windows live in the Chicago area. Did a ton of research and went with the Reznor UDAP-125 Worked great all winter kept it at 40 when not in use and could bring it to 70 in about 20 minutes. Did a horizontal vent right out the back of the building don't know if you can list websites but here is where I bought the parts
https://www.totalhomesupply.com/120000-btu-v3-power-vented-gas-fired-unit-heater/p/REZNOR-UDAP125

vent kit
http://www.littlegreenhouse.com/accessory/heater-pipe.shtml

 

[HoosierBuddy]

Jim makes a good point.

If you do a heat loss calculation that's for a steady state condition. If you want to RAISE the setpoint of the structure from 40 to 60, on a cold day, it will take a about a quarter btu per pound of air per degree of setpoint change to warm up the air in the structure.

Maybe there's an online calculator to do that for you, but in practice I'd suggest going with the next size larger heater when comparing your steady state load calculation to what the manufactuer has available. That will give you some margin of error, ability to raise the temperature fairly quickly as needed, ability to compensate of air loss when doors are opened, etc.

Phil

 

[tod]

Thanks guys, this is great information!

 

[brewchief]

What do you consider well insulated? How big are the doors? Close big city?

I looked in my files and had a 32x60x12 that I did a heat load on a couple years ago, with r-15 walls and r-19 ceiling it came out to just over 50k.

I can adjust things around and give you a pretty accurate number.

 

[finn]

I use a 75k hanging heater to bring a 32’x75’x16’ building from 42 degrees to 65 degrees.

Works fine, and we’re about as far north in Michigan as one can get.

The building is maintained at about 42-45 with in floor heat.

100k is a little bit oversized for your building, unless insulation is poor.

 

[6768rogues]

I have 40x60x14 and 36x48x14 in western NY and they each have 100K BTU Reznor hanging heaters. Our climate is similar to yours and my buildings are insulated, but not super insulated. Probably a little less insulation than you have. I use them as you do, 45 minimum, warmer when working. Both work well, and they heat right up when the thermostats are pushed up. Yours should be fine.