How much propane will i use?

[rvcoaster]

as i was working on my shop today (still insulating walls) i got to wondering how much propane i am using, and i have no idea. i think i may be burning 10 gallons a week but i am not sure.

shop is 24x30x9. R19 ceilings, R13 walls. insulated doors. furnace is 45k btu modine, i keep it at 38F at night and raise it to 53F in the day.

from searching around here it seems i may burn anywhere from 100 gallons in 5 months to 100 gallons in ONE month. ouch.

the propane installer said he put 30 gallons in my tank when he delivered it (1000# tank or 150 gallons) and today the dial on the top said "9". i have no idea what it said when he filled it, i didnt even know there was a dial until today.

have i used 21 gallons in two weeks?

 

[Chetter]

I have used as much as 1 40lb bottle in a week when it is bitter cold, 0-low teens during a week. I leave my 45000btu propane heater on 24/7 with the temp set at 48-50* once the temp comes back to the 20's-30's I can get about 2 weeks or more out of one bottle. I have R-30 attic banket and 1" thick styrofoam 4x8 sheets as well and my garage walls are wrapped and the walls have 1" styrofoam glued to the osb and then there is 1/2" osb over that which is painted white. I have insulated doors as well and no windows when I built the garage in 1996. I can turn the heat up to 60-65* and it will run for about 1/2 hour or so and it is up to temp and then I set it back. My cost to heat my garage has averaged about 250-350.00 for the entire season I heat it depending on the current cost of propane and winter temps. The propane supplier I go to has been real good at holding costs steady and not moving the price up and down almost daily which a lot of retailers do any more.

 

[trbomax]

You dont say where you are,but your insulation seems a little light to me. In northern mi min code is 30 in cielings. My shop cieling is better insulated than my house ,50 vs 30. walls in the house and shop are 30 with an outside wrap. My house is small,only 1500 ft and it runs about $350 - $450 per month from mid nov to march.I just got a fill last week and it was 211.5 gal @2.499,so $528.44 since the last fill in august. The part of the shop that is heated 24-7 with propane is only 1000 ft and this is the first year doing it.So far this season Im down about 50 gal on my 500 gal shop pig,so roughly $150 but we did not start heating out there untill around nov 1. The house is kept at 70 and the shop 45 unless we are there which averages about 40 hrs/wk.

Propane useage is hard to predict but so far I am about where I thought I should be with the shop.

 

[rvcoaster]

i'm in the fargo ND area. yes the isulation is a little light; the plan is to blow in insulation over the R19 in the ceiling when this is all done. the rafters are 2x4 truss so r38 didnt make a lot of sense to me, even the r19 sticks up past the joists quite a ways. i figure if i blow in another 6" all around that ought to be about right. i made the attic entrance box out of 1x12".

the walls? i dont know what else to do- they are just 2x4 walls. i'm still open to suggestions at this point, i'm no expert at this. from what i read you arent supposed to stuff fiberglass in too tight so r13 was the limit unless i firred out the walls with 2x2"s or something

the more insulation i get up the faster i can raise the temp from 38 to 54. took around 10 minutes today, took 30 minutes two weeks ago.

 

[trbomax]

Are the walls finished on the inside? you should blow 12" minimum of cellulose in the cieling for it to be worth the bother. My cielings are 3.5" foam board between the trusses,3/8" reflective wrap on the heated side of that with steel roof sheeting for a cieling. The finishing touch was blowing 20" cellulose above that.

 

[rvcoaster]

walls arent finished at all. i have one 30' wall nearly done with R13 but thats it. (that wall is REALLY stinking warm to stand around too

 

[trbomax]

Good. Fir it out 1.5" horizontally.You should install 1.5" sheet foam of your choice in the voids. Blue will give you an added r-13,white, r9. Tape all joints with foil tape.Cover the whole wall then with 3/8" Polar brand reflective fan fold wrap attached with 1" cap nails. Tape all joints and seams with foil tape. You have added another r-1.5 - r 3. Cover the walls with the material of your choice,they are now approx. r-26 and have a very small thermal transmission signature. An infra red heat loss imageing device will show nothing worth measureing.

edit) If you had done the OUTSIDE of the stud walls this way too before you hung the sideing you would have an r-33 wall panel with NO thermal transmission sig. This is how mine are.

 

[rvcoaster]

well, today i ran out, nine days later. i guess i am burning around 1 gallon a day.

its mighty cold in my shop this christmas.

 

[Kevin54]

If it is for instance 20F out, I can go maybe 1 1/2 months on a 120 gallon propane tank.

That is with a 45,000 BTU hanging furnace, 28'x36' garage w/8' ceilings, R30 in ceiling and R13 in the walls. Maybe spending 6-10 hours /week and 12+ hours on the weekend, keeping it at 68 in the garage. I kick it back to 50 at night.

 

[Sledneck]

Propane costs are hard to estimate, a lot depends on the temps outside.

I have a Mr Heater 45K unit in a 25 X 25 double garage, with R25 walls and R50 ceiling. I spend about $700 per year heating it.
Propane costs here are $0.69 a litre (approx 4 litres in a US gal). So quick math would indicate that I used roughly 1015 litres or 254 us gals to heat for the season Nov - Apr.

I usually leave the garage at 5C when I'm not in there.