Alternative to conventional propane heat idea

[David Roberts,Fitchburg,Ma]

I live in North Central Massachusetts, almost in New Hampshire, so it gets cold in the shop in the winter. I built a 24' x 40' 2 story pole barn shop about 5 years ago, its pretty much completed. Has R19 in walls and ceiling. I have a small pellet stove, and also another direct vent heat source, an Empire propane space heater. They are each about 35,00 BTUs, but unless I ran them continously, they just aren't enough to warm up the building. I am considering a propane house air furnace, in the 100,000 +BTU range to help, but I also had another idea. I thought about using a 250,000 to 400,000 BTU propane pool heater, they stay outdoors, so don't need venting, and I could loop the hot water into one or two Modine style heat exchangers. (the cost is reasonable for a used one also) My goal is to only heat the shop up for actual use time, mostly weekends and some evenings. Does this make sense? I await any other ideas, I don't want to go with a woodstove, I don't have acess to free wood and it requires more storage space outdoors that I don't have. thanks

[Chris Friesen]

My dad had a ~100K BTU house forced air furnace in his garage. Worked just fine. It had no ducting, just a 90 degree bend on top to blow the air horizontally. I have a 45K unit heater in my double car garage/shop (attached). I keep it just above freezing then warm it up to use it.

Water is excellent at storing heat, so anything using a hydronic heater is going to spend some time heating up the water before it heats up the shop...not so good if you just want to warm it up when you actually use it.

Not sure about your climate, but more insulation in the ceiling might make sense. I'm in the Canadian prairies and have R30 in the ceiling (but only R12 walls). Air leaks lose a lot of heat so make sure you've got good vapour barrier on the walls/ceiling and weatherstripping around any doors.

[David Kreuzberg]

I have a 30' x 52' Morton steel building with 6" of insulation in the sidewalls and 12" in the 10' ceiling.

My heat source is an 80,000 BTU forced air propane furnace with output ducting run above the ceiling to 6 - 4" x 10" diffusers. No return air ducting. Keeps the place toasty warm in the coldest weather.

Since our shop volumes, insulation and climates are similar, you may not need a 100,000 BTU furnace. Have a heating contractor size your shop for a furnace.

kreuzie

[David Roberts,Fitchburg,Ma]

I can't really afford to increase the insulation in the roof, I am stuck with R19 through out, however I guess my second best choice would be a greater than 100,000 BTU heater that can heat up the shop to >50 degrees and than use my pellet stove and propane space heater to maintain the heat. I had a high hat type heater when I was building, maybe something similar would be best. My plan is not to heat except when I am working, I can't try and maintain a reasonable heat thru the winter.

[Lee Schierer]

Wow, that seems like a lot of BTU's for less than 2000 square feet. I heat my entire house 24/7 in NW PA with a 50,000 btu heat pump and keep it constantly at 68 degrees and it only runs intermittantly. I know it gets a bit colder where you are, but needing more than twice the BTU's to heat your shop seems to indicate you have another problem with air infiltration. My walls are R-19 and I'm about R30 in the ceilings.

[Bruce Wrenn]

Because you aren't using system full time, how are you going to keep it from freezing? An oil furnace will deliver more BTU's per buck than a propane furnace. A gallon of oil, and a gallon of propane are about the same in cost. Propane has 96,000 BTU's per gallon, while oil has 146,000 BTU's per gallon.

[David Roberts,Fitchburg,Ma]

My shop does freeze in Jan and Feb, but I would like to find a less expensive way to heat it from sub 32 degree temps to working conditions when I work on weekends. I have enough BTUs to maintain a working temp, once I get it up to about 50. I don't plan to pull a permit, so adding an oil tank would stand out. I have been using a 100lb propane tank for the Empire direct vent space heater, I can throw the tank in the back of the pick up, and not bring attention to my shop in the neighborhood. Have been leaning towards a hot air furnace, with >100,000 BTUs to run for an hour or two to get the shop warming started. Electric is expensive, (so electric space heaters are out) I live in the second most expensive town for electricity in the USA. (Or so I've heard). The other choices would be towards a non vented heater, which is not where I wanted to head if I don't have too. I feel direct vented heat sources would suit be best, or my original thought of a high BTU propane powered, outdoor pool heater. The budget for improvements to the heat is only 350 to 500$, ( I just bought a new toy, a 1968 Datsun Roadster, which will live in the barn in the winter). A wood stove isn't a problem, but its the chimney, either expensive piping or building a masonry one.