Figuring gas cost for heater

[Aquaman7]

Hello,
I’m considering buying a 400k master temp heater. Out of curiosity I would like to know how much it would cost in gas per hour to run the heater. Is it true that 1000 BTU is equal to 1 therm of gas? Where I live in New Jersey it cost $.79 per therm which includes the supply and delivery charges. Is it realistic to say that to figure out the gas cost I would multiply 400 x $.79 which will give me the hourly rate? 400x.79 = 3.16 p/hour.
I’ll also need this calculation to figure out the cost to run 2 fire bowls at 65k BTU’s each.
Thanks everyone for your help.

 

[ajw22]

I think you have some typos in what you wrote but get to the correct answer.

1 Therm = 99,976.13 BTU = round up to 100,000 BTU

Running your 400K heater is 4X.79= $3.16/hour

 

[JamesW]

1 therm = 100,000 btu.

A 400,000 btu per hour heater will use 4 therms per hour.

4 therms x $0.79 per therm = $3.16 per hour.

 

[Aquaman7]

Ahhh yes. Thank you aj & James.

 

[Aquaman7]

I was just thinking, don’t I have to deduct for the efficiency of the heater?

 

[JamesW]

I was just thinking, don’t I have to deduct for the efficiency of the heater?

A 400,000 btu/hr heater uses 4 therms per hour regardless of the efficiency.

The efficiency only tells you how much of the heat transfers to the water.

The gas company does not care how efficient your heater is.

They only care how much gas you use.

 

[homegameroom]

Here is a spiffy calculator (spreadsheet) to help you figure out the cost:

Natural Gas Heating Time & Cost Calculator Spreadsheet

There have been several recent posts inquiring how long it would take or how much it would cost to heat a pool / spa using a natural gas heater. In response, I have taken on the challenge of putting together this spreadsheet to help answer those questions. It’s now ready to be test driven...

www.troublefreepool.com

 

[Aquaman7]

Got it James. Nice spread sheet home. Thank you guys.