Heating option opinions.

[3rdgendslmech]

800sf pole barn. Walls are R-19 with 7/16 osb. Open ceiling with 1" expanded foam with foil as a vapor/radiant barrier on the bottom (inside) roof purlins.
Spent this winter using a 80K btu diesel torpedo heater.
Worked great, kinda loud, kept inside at 50-60 when it was 30 and below. Didn't really notice any condensation on anything. Have a full ridge vent and soffit vents.
Looking ahead for next year.... obviously more insulation in the ceiling would be a huge factor.
I'm curious about a big Maxx heater being run off of 2 100lb tanks with a dual line set up. I'm only really interested in keeping the shop at 45 when I'm not out there, or even not even having it on at all since there isn't anything that could freeze. How long would both tanks last if I went with a 50Kbtu unit?

My other option was going to be 18-24K mini split. I like the idea of having a/c and heat but with bare minimum insulation in the ceiling I don't think it would keep up.
During the summer I'm going to try to install 2 44" ceiling fans in between the trusses to keep air moving, and that would be a huge help come winter. I used a basic oscillating house fan up on a shelf running the torpedo heater...night and day difference using a fan.

No gas to area, and barn is detached, about 100ft from access Rd.

 

[Jackfre]

Bring the load back in with insulation. I have found that insulation companies will do the job for about what I can buy the material for. Reduce the load and then make a decision on heating appliances.

 

[xyster101]

Without decent insulation in the ceiling, you will loose all your heat quickly. Is the roof insulated and then sealed or can the heat go out the ridge vent?
Fix your insulation before you do heat. Otherwise you will not buy the proper heat size device.

 

[theoldwizard1]

I'm curious about a big Maxx heater being run off of 2 100lb tanks with a dual line set up.

Are you saying 2 separate lines so you have a primary and a backup (by far the best solution).

With your current insulation and trying to maintain 45° continuously, my wild guess is less than 2 weeks in the middle of winter. You need to check with your distributor to see if they will come out and refill such small tanks.

My other option was going to be 18-24K mini split. I like the idea of having a/c and heat but with bare minimum insulation in the ceiling I don't think it would keep up.

First, I really like mini-splits, but they are expensive ! If you can live without A/C or maybe one or two large window A/C units, you can buy a lot of propane for the money you will save.

Long term (5? 10? years), the mini-split will be a win because of how little energy it uses when the outside temperature is between 40° and 80°.

The other problem with mini-splits is "buyer beware" ! You have to understand the ratings to see if it can provide adequate heat when the outside temperature goes down to 0° ! Some can some can NOT without resistance heat strips which ruins your savings !!


YOU PAY FOR INSULATION ONCE ! YOU PAY FOR THE ENERGY TO HEAT/COOL YOUR BUILDING EVERYTIME THE THERMOSTAT CALLS FOR IT !!

 

[jack stand]

I'm in with the insulate gang. With a great insulation/ air sealing "pkg" your heating & cooling decisions become minor decisions, regardless of the source.