Calculating Lp burn rate??

Quick question for hvac guys

I have an extra carrier 92% 80,000 btu furnace I’m going to throw in a pole barn.

Just need a reasonable ballpark idea of consumption or burn rate per hour of operation. I can calc loss and all that. After it’s up to temperature , it should run about 5 – 6 hours per 24 hour period based on average 40 degree differential to outside. Just need to see f I have enough in the tanks to leave it for two weeks

With your numbers you should burn about 5.25 gallons of propane per day.

Dave maze wrote:

With your numbers you should burn about 5.25 gallons of propane per day.

Thanks Dave. I was coming up with 8+ and knew that was wrong

Dave maze wrote:

With your numbers you should burn about 5.25 gallons of propane per day.

How do you arrive at that figure? I just googled it and it said to take 91,502 and divide it by the BTU rating which gives you the number of hours for 1 gallon of propane. You get a ridiculously higher number than yours. Im trusting your calc, but was wondering how you arrived at it.

CaptainMusky

I’m not a hvac guy but I think you need to flip your equation and account for efficiency.

80000/.92/91500×5.5= 5.23

Furnace rating/ efficiency/ btu of 1 gal x hours

Mr. Derek wrote:

CaptainMusky

I’m not a hvac guy but I think you need to flip your equation and account for efficiency.

80000/.92/91500×5.5= 5.23

Furnace rating/ efficiency/ btu of 1 gal x hours

Ah that makes sense! Thanks!

Btu per hour input x hours running per day ÷ by btu content per gallon of propane. I rounded up to 5.25.

Dave maze wrote:

Btu per hour input x hours running per day ÷ by btu content per gallon of propane. I rounded up to 5.25.

Thanks! I knew there was something radically wrong with the calc I found since poor Randys tank would have been empty in a couple days LOL