Gas Appliance BTU Chart: Typical BTU Ratings for Home Appliances
Typical gas appliances are rated at 100,000 BTU per hour for a house furnace, 65,000 for a freestanding range, 35,000 for a clothes dryer and 35,000 for a 30 to 40 gallon water heater. These are the approximate inputs the plumbing code uses to size gas piping when the real ratings are unknown. The rating plate on your own appliance always wins.
Part of the project planner: Planning heating, cooling and ventilation.
Gas appliance BTU chart
Input at full fire, with the gas burned per hour (natural gas at 1,100 BTU per cubic foot, propane at 91,500 BTU per gallon) and the same heat in kilowatts:
| Appliance | Input (BTU/h) | Natural gas (ft³/h) | Propane (gal/h) | Same heat in kW |
|---|---|---|---|---|
| Warm-air furnace, single-family house | 100,000 | 91 | 1.09 | 29.3 |
| Warm-air furnace, apartment (per unit) | 60,000 | 55 | 0.66 | 17.6 |
| Hydronic boiler, single-family house | 100,000 | 91 | 1.09 | 29.3 |
| Hydronic boiler, apartment (per unit) | 60,000 | 55 | 0.66 | 17.6 |
| Combination boiler, single-family house | 120,000 | 109 | 1.31 | 35.2 |
| Combination boiler, apartment (per unit) | 75,000 | 68 | 0.82 | 22.0 |
| Storage water heater, 30 to 40 gallon | 35,000 | 32 | 0.38 | 10.3 |
| Storage water heater, 50 gallon | 50,000 | 45 | 0.55 | 14.7 |
| Tankless water heater, 2 GPM | 142,800 | 130 | 1.56 | 41.9 |
| Tankless water heater, 4 GPM | 285,000 | 259 | 3.11 | 83.5 |
| Tankless water heater, 6 GPM | 428,400 | 389 | 4.68 | 125.6 |
| Circulation or side-arm water heater | 35,000 | 32 | 0.38 | 10.3 |
| Range, freestanding | 65,000 | 59 | 0.71 | 19.0 |
| Built-in oven or broiler | 25,000 | 23 | 0.27 | 7.3 |
| Built-in cooktop | 40,000 | 36 | 0.44 | 11.7 |
| Clothes dryer | 35,000 | 32 | 0.38 | 10.3 |
| Gas fireplace, direct vent | 40,000 | 36 | 0.44 | 11.7 |
| Gas log set | 80,000 | 73 | 0.87 | 23.4 |
| Barbecue (built-in or connected) | 40,000 | 36 | 0.44 | 11.7 |
| Gas refrigerator | 3,000 | 3 | 0.03 | 0.9 |
Source: the table of approximate gas input for typical appliances in the plumbing code, as reprinted in county gas pipe sizing handouts. Appliances only burn at full input while the burner is on: a furnace cycles with the thermostat and a range rarely has every burner on high.
How to read your appliance's rating
- Find the rating plate. Furnaces and water heaters have it inside the access panel; ranges under the cooktop or in the drawer; dryers inside the door or on the back. Look for "Input" in BTU/h (sometimes written MBH, thousands of BTU per hour).
- Check the gas type. The plate says natural gas or LP (propane). The burner orifices differ, so an appliance must be converted with the maker's kit before switching gas.
- Output is not input. A furnace plate shows both. A 95% furnace with 100,000 BTU/h input delivers about 95,000 BTU/h of heat to the house.
Adding up a house
To check whether a meter, a propane regulator or a gas line can carry everything at once, add the inputs of every appliance on it. A typical house with a gas furnace, water heater, range and dryer:
| Appliance | Input (BTU/h) | Natural gas (ft³/h) |
|---|---|---|
| Furnace | 100,000 | 91 |
| Water heater (40 gal) | 35,000 | 32 |
| Range | 65,000 | 59 |
| Dryer | 35,000 | 32 |
| Total if all run at once | 235,000 | 214 |
That total is about 2.6 gallons of propane an hour if everything ran flat out together, which they rarely do. A propane tank runtime calculator turns any rating into hours from a cylinder or a bulk tank, and how long a propane tank lasts has the charts for grills, heaters and furnaces.
Gas or electric: the same heat in kilowatts
One kilowatt is 3,412 BTU per hour. The last column of the chart is the electric power that would give the same heat, which shows why gas ranges, dryers and tankless heaters would need very large electric circuits. Convert any figure with the BTU converter, or see the BTU conversion chart for tons, watts and therms.
Sizing a new appliance
- Furnace: size to the heat loss of the house, not the old unit. Use the furnace size calculator.
- Tankless water heater: size by flow and groundwater temperature with the tankless water heater calculator and the tankless GPM chart. Large units may need a bigger gas line than the old tank heater.
- Backup power: a generator on natural gas or propane is rated in watts, not BTU. See the generator wattage chart.
Safety: gas piping, connections and conversions are jobs for a licensed installer in most places, and usually need a permit. Fit carbon monoxide alarms near bedrooms, and if you smell gas leave the house and call the gas company from outside.
Frequently asked questions
How many BTU does a gas range use?
A typical freestanding household range is rated about 65,000 BTU per hour with every burner and the oven on: about 59 cubic feet of natural gas or 0.71 gallons of propane an hour. The label on the range gives the exact figures for each burner.
How many BTU is a gas dryer?
About 35,000 BTU per hour, which is 32 cubic feet of natural gas an hour while the burner is on.
How many BTU does a gas furnace use?
The code table assumes 100,000 BTU per hour for a single-family furnace (91 cubic feet of natural gas an hour), but furnaces are sized to the house. Check the rating plate, or size a new one with the furnace size calculator.
How do I convert BTU to cubic feet of gas?
Divide the BTU per hour by 1,100, the average heating value of natural gas used in the pipe sizing method. A 35,000 BTU/h dryer burns about 32 cubic feet an hour. For propane divide by 91,500 BTU per gallon.
How many therms does an appliance use?
A therm is 100,000 BTU, so a 100,000 BTU/h furnace burns one therm per hour of running, and a 35,000 BTU/h water heater about a third of a therm.
Can I use this chart to size a gas line?
Only as a starting point when the real ratings are unknown. The pipe size depends on the total load, the length of the run, the pipe material and the gas pressure, from the tables in your plumbing or fuel gas code. Gas piping usually needs a permit and a licensed installer.
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