# Figuring gas cost for heater

#### Aquaman7

##### Well-known member
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.

#### ajw22

Gold Supporter
TFP Guide
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

Last edited:
Aquaman7

#### JamesW

TFP Expert
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

##### Well-known member
Ahhh yes. Thank you aj & James.

#### Aquaman7

##### Well-known member
I was just thinking, don’t I have to deduct for the efficiency of the heater?

#### JamesW

TFP Expert
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.

Bronze Supporter

#### Aquaman7

##### Well-known member
Got it James. Nice spread sheet home. Thank you guys.

Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.

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