Heater (Pool or Spa) Cost of operation of Propane heater

[mnittler]

How do I calculate the fuel cost of operation of a spa or pool propane heater? Last Saturday I routed my spa heater to the pool and raised the temperature of the pool 14 degrees in 6 hours to make it tolerable to swim. The heater never reached setpoint so it was on the entire 6 hours.
My spa propane heater is rated 400,000 btu.
Assume $2.35 per gallon of propane
How do you calculate the gallons of Propane used per hour?

 

[jblizzle]

I think it is close to this:
1 gallon propane = ~ 92,000 BTU
Heater = ~400,000 BTU/hour

So in 6 hours, you used 2,400,000 BTU / 92,000 = 26 gallons of propane = $61

Your specific question: 400,000 BTU/hr / 92,000 BTU/gallon = 4.35 gallons / hr ... assuming the heater stays on the entire time

 

[Bama Rambler]

JB beat me but our answer is the same.

The heater is rated for BTU/H so in 6 hrs you used 2,400,000 BTU's or about 26 gallons of propane.

Propane has about 91,500 btu per gallon so that heater will use about 4½ gallons per hour

 

[mnittler]

Thanks for the input. I guess using cowboy arithmetic I can pretty well assume $10/hr in 2013 propane prices of $2.35 in my area. Part of the cost of enjoying a pool.
I don't know if it is or ? The kids and grand kids (14 swimmers in all) are still talking about swimming when it was cold outside. Memories are forever.

 

[Christian]

Sounds like the party was a hit so I'd go with over !