which friggin heater?

[jaysonsk5]

hey guys i have been lurking around for a while. i have a 30x40x12 pole bulibing that i use as a shop for auto, tractor repair, woodworking you know basicly everything. the end of last year i framed out the walls and ceiling 24 on center. i then put up r19 kraft faced on the walls and ceiling. i have noticed a difference inside the shop since. it is about 20 degrees warmer inside than out. im not shure how big of a heater to use? i have a concrete floor with a drain, 2 10x10 insulated doors, 1 36" sevice door and 1 window. i have looked at alot of options but i'm not sure. it would be lp for fuel. i'm not convinced that a 75k haning unit would be big enuff. why not just use a residetal furnace? i have been using a mr. heater 200k heater and now that it is insulated it makes me ill. anyone have some helpfull insight? i'm in eastern iowa and cold. thanks in advance.

 

[Shocker]

Man, I think that a 75k btu propane Mr Heater or the equivalent would be good for your shop.

I figured an average temp of 20 degrees in winter with the delta to 60 degrees. Math works out to about 76k btu.

 

[jaysonsk5]

i have run the numbers also. my concern is that 75k seems a little small. last week it was cold here, negitive temps with wind chill in the -30 range. i have been reading a lot of posts from others on the board, however they seem to run the 75k in smaller shops than mine. i,m not sure if the extra volume of the 12' side wall will make harder for it to heat?

 

[jdkenyon]

I thought a 45k was going to work for me but after reading this I am not so sure. Mine is a stick built 32x32x12 with R19 in the walls and eventually R48 in the ceiling. Right now I am about R13 in the ceiling. I have one 36" man door, 4 windows, 1 10x10 and 1 12x10 over head door. Both are insulated to R12. Using one 30k btu space heater and a Kero-Sun at around 18k btus I can raise the temp from around 35 degrees to 55 in about an hour when outside temp is 20 and the sun is down.

 

[regguy1]

I thought a 45k was going to work for me but after reading this I am not so sure. Mine is a stick built 32x32x12 with R19 in the walls and eventually R48 in the ceiling. Right now I am about R13 in the ceiling. I have one 36" man door, 4 windows, 1 10x10 and 1 12x10 over head door. Both are insulated to R12. Using one 30k btu space heater and a Kero-Sun at around 18k btus I can raise the temp from around 35 degrees to 55 in about an hour when outside temp is 20 and the sun is down.

Here is a guide to size your heater by calculating the cu ft of building

http://www.mrheater.com/upload/10-27-08 MH 2008 NT Heat Guide.pdf

 

[bd8134]

I have a 32x40 with the majority at 12' ceiling. R16 sprayed foam in the walls, R30 in the ceiling, 3 R16 garage doors, no windows. I have a 45k propane heater. Thermostat set lowest at 50. When it is outside at 20, it takes about 2 hours maybe longer to get it from 50 to 65, not good. It then holds it pretty good.
This heater is obviously not big enough but I only intend to replace it when it breaks.
A 75k sounds a nice size for you jaysonsk5, anything bigger might just keep cycling all the time. The 75k would hold it most likely give you a more even temp and useable in the fall and spring.

 

[trythis]

I have a brick wall 48 x 40 16 foot ceiling. I put in a 40 foot Detroit radiant HL2 (2 stage) tube heater. It runs 100K BTU and 60K btu. I have no insulation, a 12x 12 door, uninsulated. I can keep it at 40 no problem even if its 4 degrees F outside. It doesnt run in 100K mode for long, or often. Only if I leave the door open a long time, or if i raise the thremostat.

Its a big L shape, there is an office in one corner.

I havent gotten a bill yet, but the heater dos its job and seems like plenty.

 

[PurdueSD]

Mine is 30x56 or more importantly 18,000 cubic feet.
R19 walls, R30 ceiling and alot of overhead doors

Ive got a 75K BTU mr heater. I live in SW Indiana. Last week we had temps in the single digits and the heater never struggled to keep up.

30x40x12 =14,400 Cubic feet but your climate is probly a little colder.

If it were me i would start with (1) 75K BTU unit. You could always add another 30K BTU one later. I would bet 75 is the right number for you, but im not an HVAC expert either...just speaking from my experience.

Goodluck!

 

[jaysonsk5]

thank you for your insight

 

[getem2nd]

i sized this heater for you with the dimensions given by you. this heater is one of the best on the market. it is sealed combustion and even the motor for the blower is sealed so there are no worries working with fuels or chemicals. being a plumber/ pipefitter i installed the Modine Hot Dawg 30k btu unit in my garage recently and its the best move i ever made. you will find that the Modine hot dawg heater is one of the only heater that complies with state plumbing codes. its easy to install. good luck

 

[getem2nd]

sorry forgot to add the link...... here it is! http://www.greendroplet.com/product_info.php?products_id=1090

 

[jaysonsk5]

thanks. i guess i thought that the 75k was to small but the "pros" kept on that it would be fine. i was kinda thinking that the 100k would be the ticket but i wanted to see if anyone else shared my same opinion. sorry for the odd post. thanks agin