Running a whole-home standby generator typically costs roughly $40–$90 per day on natural gas and about $90–$150 per day on propane, depending on the unit’s size, how much of your home it is powering, and local fuel prices. Natural gas is usually cheaper to run and never needs refilling; propane costs more per day but keeps running independently of the gas utility. (These are estimates — your actual cost depends on load and fuel prices.)
What determines your running cost
- Generator size and load. A bigger unit, or one powering your whole home including A/C, burns more fuel than one running just the essentials.
- Fuel type and local prices. Natural gas is billed through your utility; propane is purchased by the tank. See propane vs. natural gas for your standby generator.
- How long the outage lasts. Cost is per hour of runtime, so a multi-day hurricane outage costs more than a short one.
Running cost on natural gas
Because natural gas feeds continuously from the utility line, you never refuel and the day-to-day cost is modest — often in the $40–$90 per day range at typical household load, more if you are running the whole home at full tilt.
Running cost on propane
A home standby unit uses roughly 2–3 gallons of propane per hour under load, so a full day of backup can run about $90–$150 at typical load. The trade-off is independence: propane keeps running even if the natural gas utility is affected.
How to keep running costs down
- Right-size the unit. An oversized generator wastes fuel; proper sizing keeps costs efficient.
- Use smart load management. Prioritizing circuits lets a right-sized unit cover more without overworking.
- Keep up with maintenance. A well-tuned engine runs more efficiently — see our maintenance schedule.
Frequently asked questions
Is it expensive to run a whole-house generator?
It is modest on natural gas and higher on propane, but usually far less than the cost of spoiled food, frozen pipes, or a hotel stay during a long outage.
How much propane does a standby generator use?
A typical home standby unit uses about 2–3 gallons per hour under load, and less at partial load.
Does a standby generator run constantly during an outage?
Yes, but it modulates with your home’s demand, so it burns less fuel when less power is being used.
Want help choosing the right size and fuel to keep running costs low? Book a free consultation with Texas Star Power, serving Houston and Montgomery County.