Shop heat decision

The Fuji mini-split I installed has a console like interior unit that mounts high on the wall. There are several other options for the interior unit: Floor mount, Mount in the ceiling between joists, mount in the ceiling/attic and use short runs of conventional AC or flexible AC duct. The interior console units are most common but with a little looking around you will find there are a lot of options. The Fuji I installed is one of the highest efficiency rated units and I REALLY like it! Dead silent!
 
I have a Mitsubishi Electric Split-System Heat Pump in my 26' x 40' x 11' shop building. Works well for A/C, struggles a bit when it gets below 20 degrees outside.
 
gi_984 said:
Went from bare walls, zero insulation, and wearing heavy winter coat/boots to this:

http://www.reznorhvac.com/en/na/products/udas

Rated for commercial and residential use. So the insurance company has zero issues with it. Also got the recommended fresh air intake/vent. Separate combustion chamber so you aren't burning the dust and crud in the shop air. So better air quality. Got the 45K BTU size.

Fiberglass insulation in the walls (R-13), Insulated garage doors & entrance door, Drywall interior walls & ceiling,blown in fiberglass in ceiling (R-60). Thermostat set at 40. During the cold months it only runs when the temps stay below freezing. Easily holds it at 40. When I want to work in the shop area just turn it up to 68. Takes about half an hour to bring to temp. Very little increase in the gas bill. Was expensive but worth it. Only regret not doing it before moving in.
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In my old shop I finally got this same unit, best desision I ever made! Went from the open flame propane infrared heat to the reznor separate combustion chamber (no open flame in the area your heating) What hasn't been mentioned is when you have a open flame you are creating moisture. Moisture and machine tools are a bad idea. Fighting rust on Tools/ metal/ machines, etc. went away after getting the Reznor.
 
"gi_984, How big and high is your shop area?"
Approximately 38 feet by 28 feet, 9 foot 8 inch tall ceilings. The 45K BTU works fine for this space. The biggest heat loss is around the garage doors (even with insulation and weatherstripping). My heater runs off natural gas.
 
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You need to do a heat loss calculation as suggested. In my small shop (about 18 x 20) I use a sidewall venting condensing gas furnace gotten off craigslist for $50. Easy to install and very "efficient." The only real issue is that it has to be drained in freezing weather. With a good inlet air filter it can serve double duty as a room air cleaner for woodworking. Some of these are "multipoise," meaning you can hang them up horizontally if you have the headroom.

In some places, if the alternative is propane, a heat pump might be a good alternative. Prices vary a lot from place to place.

Radiant floor heating gives good comfort but is slow-responding, so is good for continuous heating but not so much for I-turn-it-on-when-I'm-working.

Just my thoughts. Not a HVAC designer.
 
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