28x36x13 Pole Barn Unit Heater

[bagsanthony]

All, I just got done installing a Modine Hot Dawg 75,000 BTU heater in my 28x36x13 pole barn in Western NY. The pole barn is 1990s construction. Insulation is there, is it the greatest, NO! I do plan on adding additional batts in the ceiling as I have access. I have heard a lot of people talk about going small with heaters to avoid short cycling.... that's great but with a barn I feel going just slightly bigger is better. Also, what was strange was I had local guys tell me that I needed 100-125,000 BTU's. That did not seem reasonable. I plan on keeping the space at 46 unoccupied and bumping it to 55-58 working.

Wanted to get your thoughts, does my heater size make sense? Should I do I anything different with the heat turning on/off? Thanks!

 

[AC-WC]

You should really run a heat load calculation. Try calculatornow.com.
I think 75k should be fine especially if you add more insulation.

 

[dscheidt]

Also, what was strange was I had local guys tell me that I needed 100-125,000 BTU's. That did not seem reasonable.

It’s not, if you plan on keeping it heated. If you’re turning on the heat when you get to the shop, an oversized heater will bring it to temp faster. It will also recover faster when the door is opened. They may be sizing for that, they may be knuckleheads who don’t know how to size stuff, they might be thinking they make more if you buy a bigger unit. They might be all of those, hard to say from here.

 

[bagsanthony]

It’s not, if you plan on keeping it heated. If you’re turning on the heat when you get to the shop, an oversized heater will bring it to temp faster. It will also recover faster when the door is opened. They may be sizing for that, they may be knuckleheads who don’t know how to size stuff, they might be thinking they make more if you buy a bigger unit. They might be all of those, hard to say from here.

Agreed. Just listening to them come up with the values, I knew they had no idea on what they were talking about. I did speak to an engineer who I bought the Modine unit from. He was confident that a 60K would suffice. Again, this is Western, NY very cold! I think people in the area are thinking full commercial automotive shop- doors opening constantly and limited insulation.

 

[finn]

The 75k overhead heater in my garage (32x54) brings the temperature up from 45 to 65 just fine. It takes longer if the building and contents are in the teens or twenties, but it still has the capacity to do it.

Any larger and it would be short cycling.

I have the same 75k btu heater in my shop that’s got a 32x75 “work area and 16’ ceilings. I use it to bump the temperature from the low forties to 65 when I am working. Again, I think it would short cycle if it was any larger.

 

[bagsanthony]

Thanks

 

[bagsanthony]

The 75k overhead heater in my garage (32x54) brings the temperature up from 45 to 65 just fine. It takes longer if the building and contents are in the teens or twenties, but it still has the capacity to do it.

Any larger and it would be short cycling.

I have the same 75k btu heater in my shop that’s got a 32x75 “work area and 16’ ceilings. I use it to bump the temperature from the low forties to 65 when I am working. Again, I think it would short cycle if it was any larger.

Awesome, thanks for your reply. So based on roughly 1,000 sqft, 75k should be plenty if not oversized. 65 degrees is way too warm for me lol. I usually like 56-58.