Shop heat decision

My experiences with radiant in the floor are all positive. Building is 28' x 40' with 10' ceilings with one bay being a high bay. 6" walls, trusses with 6" foam in ceiling. 2-10' insulated garage doors. No windows ! I use a oil fired 30 gal. HW heater, 1100 ft. pex tubing on about 6" centers and 12" or 18" from edge of reinforced slab. Slab is insulated on bottom and sides with 2" owens-corning foam. I use about 175 gallons fuel a yr. to heat and keep at 50 degrees during a cold upstate NY winter.
 
MikeInOr said:
I have a mini-split heatpump that does a really nice job. Much more efficient that a straight electric heater in my neck of the woods and much less hassle than propane. I installed it myself.

When I was growing up my father put an old natural gas forced air furnace in the corner of the garage... without any ducting. It did a nice job. Make sure you put some kind of dust collection on the intake to filter the shop air and keep the innards relatively clean and efficient.
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I too installed my own mini-split. Takes up very little space on my garage wall and it's great for the summer, too.
 
Do the mini-splits allow for air ducting or are they just a single radiator/fan unit on the wall? Cooling would be a nice bonus since the sun actually does come out sometimes here.
 
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Reddinr said:
Do the mini-splits allow for air ducting or are they just a single radiator/fan unit on the wall? Cooling would be a nice bonus since the sun actually does come out sometimes here.
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A mini split works just like a typical heat pump/air conditioner. It is just a lot smaller. The indoor unit mounts on the inside of any wall, and the outdoor unit is like a miniature heat pump or A/C unit. They are quick and easy to install. The hoses are pre-charged, so all you need to do is run the hoses through the wall, mount the outdoor unit on concrete or similar, hang the indoor unit on the wall, and run wiring to both. It is as quiet as the central heat in a house, perhaps more so. A lot of people put streamers on the outlet so they can tell if it is running. They may not be the best choice is a really cold climate, because they are taking the heat out of the air, and that air is COLD, so it is less efficient and has less output under those conditions. In more moderate climates, they are almost always a winner. They are hugely more efficient than resistance heat and window air conditioners. HUGELY. They are also a lot less expensive than you think. Advice: look very closely at the efficiency numbers and quality ratings before buying, and look for ones with really high ratings. The cost of power quickly overtakes a few dollars saved on the initial purchase and installation. My other advice is to insulate and stop air infiltration really well before adding any heat or cooling to a shop. Otherwise you are just throwing money away heating and cooling the outdoors.
https://www.energystar.gov/products/heating_cooling/ductless_heating_cooling
 
Electric heat is 100% energy efficient. Assuming you meant cost effective which it is not. Clean, convenient, and expensive on day 2

Kinda like Inkjet printers!!
Lol
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Heat pumps and air conditioners are MORE than 100 percent efficient under typical conditions. That is possible because they are not creating the heat, they are only moving it from one place to another. A decent mini split will be about 400 percent efficient while heating at 35F outdoor temperature. It gets worse as it gets colder. Same thing happens with cooling, in reverse.
 
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.
 
gi_984, How big and high is your shop area? That unit is similar to the one I have now but am thinking of trading in for something less noisy. The fan in mine is very loud.
 
I did a little more research and found a surplus high-efficiency propane furnace/air-handler locally. I think I will go with the propane / forced air route. It seems to make sense for my situation. I found a bunch of resources for HVAC sizing, laying out ductwork and air-handler sizing. A little complicated but interesting! If nothing else, a challange! These all appear to me to be open-source documents and tools.

BTU Calculator: http://www.calculator.net/btu-calcu...=50&temperatureunit=f&calctype=heat&x=76&y=24

ACCA Manual D is apparently the bible for HVAC mechanicals.

ACCA Manual D Spreadsheet: https://www.acca.org/viewdocument/acca-speed-sheet-for-manual-d

ACCA Manual D (Newer draft on ACCA Website): https://www.acca.org/HigherLogic/Sy...tFileKey=7fc1b1b0-d18d-8eb1-7949-3fa6ed32d50f

ACCA Manual D Video:
 
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