Author	[Modern View]
George Marsh 03-06-2013 12:20:29 50.104.195.160 Report to Moderator	sflem849, Decided to crunch some numbers. My 30x40 pole barn has a 6 inch floor. Using my floor, it will take 444,444 BTU's to change concrete just 10 degrees. If I used a 5500 watt electric water heater, it would take 23.7 hours to do the job. Not factoring in any heat losses. SOOOOOO, it will cost me $15 to change my floor temp 10 degrees. If anyone wants to check my calculations: specific heat for concrete is 0.5 1 yard of concrete is 4000 pounds. these numbers may not be exact, but close. I was trusting my old memory. George [Reply]   [No Email]
sflem849 03-07-2013 04:42:00 69.197.84.39 Report to Moderator	Re: Shop Floor Heat in reply to George Marsh, 03-06-2013 12:20:29   Quoting Removed, click Modern View to see So wouldn't this be true for propane? There are 91,300 btus in a gallon of propane. Propane is around $3/gal right now. So it would cost $14.60 to heat the same floor with propane. About the same. Don't you need to account for efficiencies somewhere in the calculations?   [Reply]  [No Email]
GordoSD 03-06-2013 15:49:21 216.106.243.55 Report to Moderator	Re: Shop Floor Heat in reply to George Marsh, 03-06-2013 12:20:29   How many KWH to MAINTAIN it at say55 degrees?   [Reply]  [No Email]
George Marsh 03-06-2013 19:39:55 50.104.195.160 Report to Moderator	Re: Shop Floor Heat in reply to GordoSD, 03-06-2013 15:49:21   GordoSD, Heat loss is calculated by knowing the R rating of walls, ceiling, windows, doors, loss through ground, not to mention air infiltration. You also have to know the delta temp between inside and outside temps. Windows are rated in U ratings which you convert to R. R = 1/U Oh, you also need to know the surface area of each part of the building too, doors, windows, walls, ceiling, floor. Give me that, the rest is very simple. It's very cheap to heat just air. George   [Reply]  [No Email]