Question about heater sizing

[isaac338]

I know this question is asked pretty often, but in my searching I haven't found anyone with a building quite like mine.

My shop is 24x24, the ceiling is 16 feet high in the middle, and 12 feet high at the edges. I have a loft upstairs that covers half of the floor space (so like 15x24) but is open to the downstairs (just a railing). The loft has couches and stuff and is used pretty frequently.

The walls and ceiling are insulated pretty well, and I have two double glazed skylights, but three or four old sash windows in the downstairs. The doors are big hinged wooden doors that have some pretty significant leaks around them (which could probably be fixed).

Given this, is the 45,000 BTU Big Maxx big enough, or should I spring for the 75,000? I'd like to keep the shop at a steady 12 or 15 degrees to keep moisture off the machinery and keep stuff from rusting. I also don't want the thing short cycling constantly.

I can post a pic of the building if it'll help.

Thanks for any advice..

 

[RAMBIN]

first question....occasional heat..or heated all winter?...

 

[isaac338]

Heated all winter if it's not overly expensive - the main goal isn't really to keep it super warm all year (unless I'm out there for whatever reason), but to keep it at like 10-12 degrees to keep the rust off the machinery.

 

[isaac338]

Does anyone have any advice? The price for the tank install is surprisingly cheap from the local propane co and I'd like to get this done soon..

 

[bomber]

I'm no expert, but given your heat loss issues, I'd go as big as I could -- your building will "look" bigger to the heater with the single pane windows and leaky doors

 

[gotta56forme]

have you tried something like this...

http://http://www.heatershop.com/btu_calculator.htm

 

[isaac338]

Yeah, I've looked at several calculators and they all give pretty varying answers. That one puts me at about 46,000 BTU for a 10 degree temperature increase with loose leaky insulation.. I'm still undecided

 

[mikester]

My garage is 22 x 30 with an 8' ceiling, 2 insulated 9' doors and I have a 45K Hot Dawg and I thing I could have gone with the 30K. I doesnt seem to short cycle but it runs for 5 minutes and the garage is warm. Ive got it mounted on on the far side and when the thing comes on you can feel the blown heat 25' away.