May 20, 2022

How Much Fuel Does a Generac Generator Use?

You have many important factors to consider when deciding what Generac home generator to install. Fuel consumption rates and their associated costs are first and foremost for many homeowners. Rates vary depending on the generator’s fuel type and capacity, as well as the electrical demand it’s under. Compare your options here to help you find the right Generac generator for your needs.


Generators once primarily ran on gasoline or diesel fuel, but propane and natural gas are fast becoming the most popular options for home and commercial use because of their efficiency, eco-friendliness, and longer run times.

After all, consider that 24-hour tanks are the most common size for portable gasoline generators. On the other hand, propane-powered standby generators draw from tanks that range in size from 250 to 1,000 gallons, providing multiple days or even weeks of backup power for your home. Most impressive of all are natural gas generators, which attach to your home’s gas lines for an infinite supply of fuel.


As you might imagine, larger generators burn more fuel, especially if you push them to their maximum power output. A typical Generac home generator might be 22 kilowatts (kW), which means it can supply up to 22,000 watts (W) at a time. For many homeowners, this is enough to power the “essentials.”

To determine if 22kW is large enough for your needs, add up the wattage of everything you want to run at once during a power outage. Here are the typical wattage requirements of some high-usage appliances:

  • Ovens: 2,200W
  • Coffee makers: 700W – 1,400W
  • Refrigerators: 150W – 400W
  • Microwaves: 950W – 1,750W
  • Dishwashers: 1,200W – 1,500W

Remember, the startup wattage is often much higher than the running wattage, so to prevent exceeding your generator’s limits, you’ll want to overshoot your estimate by about 10kW.


A typical propane-powered 22kW Generac standby generator burns about 2.1 gallons per hour at half load. At around $2.50 per gallon, that’s $110 per day. At full load, a propane generator may consume up to 3.6 gallons per hour, costing almost $220 per day. If necessary, you can run your generator for three to 20 days straight, depending on tank size and your exact usage.

By comparison, a 22kW Generac standby generator connected to your home’s natural gas supply consumes about 5.9 cubic meters of fuel per hour at half load. While the exact cost depends on the price of natural gas, this could come to about $20 to $30 per day. At full load, the generator consumes about 9.7 cubic meters of fuel per hour, costing about $30 to $50 per day. As a Certified Select Generac PowerPRO dealer, Seidel Electric Inc is highly qualified to install and repair Generac generators. We have served homeowners and businesses throughout Blairstown, NJ and the entire Tri-State Area since 1944. To learn more about our generator services and financing options, please contact us at (908) 760-6941.