Gas Stove BTU Turn Down Rate Definition – In a lot of my gas stove and fireplace articles I talk about the turn down rate. This rate is the difference in BTU ratings between the highest and lowest settings on the fireplace or stove. The bottom line benefit to this is the more range that have, the more you can enjoy your gas stove or fireplace. The lower that your gas stove or fireplace can go the more often you can turn it on for longer and enjoy the ambiance of the fire.
So I think we should start by defining a couple things:
- BTU = British Thermal Unit, the amount of heat required to heat one pound of water, from 39° to 40° Farenheit.
- There are 91,600 BTU in a gallon of Propane (LP) gas.
- There are 100,000 BTU in a therm of Natural Gas. A therm is how it is normally billed to you.
So now that we got those definitions out of the way let me tell you how to apply them to a gas stove or fireplace. A gas stove is rated by BTU, but that is not the BTU’s coming out of the unit. It is the BTU going in. So if I have a stove rated for 30,000 BTU’s that simply means it will burn a gallon of propane every 3 hours, and a therm of natural gas every 3.25 hours. Ironically this has nothing to do with how efficiently the stove/fireplace will convert that fuel into heat in your home.
So bottom line, ALL BTU RATINGS ARE INPUT RATINGS, or the amount of gas being burned.
The turn down rate is the difference between the high BTU rate and the low BTU rate. This industry average rate goes from no adjustment in some inexpensive builder grade fireplaces. To a lot of the middle of the road units around 40% – 50%. And some higher end units up to 85% turn down, like some Mendota Fireplaces.
The biggest benefit to you as a consumer is that with a large turn down (range) you can use your gas stove or fireplace a lot more days out of the year, by being able to enjoy the ambiance of a small glow but not heat yourselves out of the room in 15 minutes.
Hope that helps you understand some industry lingo.
The Stove Guy