tmshort
Well-known member
All-
Yet another heating / cooling question. Here are the basics:
Central Indiana. Detached shop. 24x36 on the ground, concrete slab. Walls are 2x4 with R-13. No windows downstairs, 2 exterior doors and 2 insulated overhead garage doors. 10' ceilings. The shop is of a gambrel roof design, and there is finished upstairs space which I would like to heat as well. It is insulated with R-19 in the 2x6 space between the sheetrock and the roof. There are several windows upstairs. There is an open stairway in the corner which leads to this space, so it is fairly contiguous with the downstairs.
I did not build this - came with the house. I would have insulated better, but it has pretty standard R-13 and 19 in the walls / ceiling. I have some work to do on sealing the doors / windows.
Last winter I heated with a 10kW electric heater which I installed (shop has its own 200A service). I have a wifi t-stat to control it, and keep it around 44F when I am not there. Electricity runs about 0.08+/kwh. The unit is downstairs. We had an unusually cold winter last year, and I spent some serious cash heating the place. Plus, it takes a long time for the 10kW heater to heat the place up to a comfortable temp for working.
I live in the country - no natural gas available. I have a 500 gal propane tank buried elsewhere on the property, but it is 300'+ away from the shop, with obstacles in between (house, pool, etc).
I've considered the following options and would like thoughts / input:
- mini split system.
- the good here is that the new ones are efficient. I would also have AC for the summer, but the shop stays pretty cool as it is tucked along the N side of the woods and well shaded. I don't do as much indoor work in the summer, as I am busy outside with garden / orchard etc.
- another benefit is the use of a dual system, with one unit upstairs and one downstairs to even out temps
- I can do the install, but it is not something I have done and there would be some learning curve.
- propane forced air
- I've looked at the Modine high efficiency forced air units (http://www.modinehvac.com/web/Greenhouse/Greenhouse-Heating-Solutions/Effinity93-High-Efficiency-Gas-Fired-Unit-Heater.htm#.VG2xZdLF9SA) which seem great, easy to install, vent through PVC.
- downside here is that I'd need another propane tank. Have not looked into costs of rental vs purchase, etc.
- I'm not exactly sure what size; I've run all kinds of calculators online, and am guessing at the 85,000 BTU unit. Any thoughts?
- Is there any downside to the units that have a sealed combustion chamber? Does using outside air decrease the overall efficiency of the unit? Just wondering if pulling in 0F air affects how well the heater can heat the inside of the building.
Thanks in advance for any thoughts / analysis. I'd be interested to hear what you all think about sizing, type of heat, etc. The 10kW heater I have works, but it takes a couple of hours to get up to temp, and is undersized for what I need.
Yet another heating / cooling question. Here are the basics:
Central Indiana. Detached shop. 24x36 on the ground, concrete slab. Walls are 2x4 with R-13. No windows downstairs, 2 exterior doors and 2 insulated overhead garage doors. 10' ceilings. The shop is of a gambrel roof design, and there is finished upstairs space which I would like to heat as well. It is insulated with R-19 in the 2x6 space between the sheetrock and the roof. There are several windows upstairs. There is an open stairway in the corner which leads to this space, so it is fairly contiguous with the downstairs.
I did not build this - came with the house. I would have insulated better, but it has pretty standard R-13 and 19 in the walls / ceiling. I have some work to do on sealing the doors / windows.
Last winter I heated with a 10kW electric heater which I installed (shop has its own 200A service). I have a wifi t-stat to control it, and keep it around 44F when I am not there. Electricity runs about 0.08+/kwh. The unit is downstairs. We had an unusually cold winter last year, and I spent some serious cash heating the place. Plus, it takes a long time for the 10kW heater to heat the place up to a comfortable temp for working.
I live in the country - no natural gas available. I have a 500 gal propane tank buried elsewhere on the property, but it is 300'+ away from the shop, with obstacles in between (house, pool, etc).
I've considered the following options and would like thoughts / input:
- mini split system.
- the good here is that the new ones are efficient. I would also have AC for the summer, but the shop stays pretty cool as it is tucked along the N side of the woods and well shaded. I don't do as much indoor work in the summer, as I am busy outside with garden / orchard etc.
- another benefit is the use of a dual system, with one unit upstairs and one downstairs to even out temps
- I can do the install, but it is not something I have done and there would be some learning curve.
- propane forced air
- I've looked at the Modine high efficiency forced air units (http://www.modinehvac.com/web/Greenhouse/Greenhouse-Heating-Solutions/Effinity93-High-Efficiency-Gas-Fired-Unit-Heater.htm#.VG2xZdLF9SA) which seem great, easy to install, vent through PVC.
- downside here is that I'd need another propane tank. Have not looked into costs of rental vs purchase, etc.
- I'm not exactly sure what size; I've run all kinds of calculators online, and am guessing at the 85,000 BTU unit. Any thoughts?
- Is there any downside to the units that have a sealed combustion chamber? Does using outside air decrease the overall efficiency of the unit? Just wondering if pulling in 0F air affects how well the heater can heat the inside of the building.
Thanks in advance for any thoughts / analysis. I'd be interested to hear what you all think about sizing, type of heat, etc. The 10kW heater I have works, but it takes a couple of hours to get up to temp, and is undersized for what I need.
