Costs, Runtime & Maintenance FAQs

Plan for outage operation with inspection and service stops, not a guaranteed number of uninterrupted hours. Follow your model’s limits for load and operating conditions, fuel supply, oil checks, and shutdown/cooldown before maintenance. Fuel on hand alone does not establish safe runtime.

One example: Generac G007325-0, an air-cooled standby model rated at 22 kW on liquid propane (LP) and 21 kW on natural gas (NG). Its published NG use is 221 ft³/hour at half load and 311 ft³/hour at full load. LP use is 2.45 gallons/hour at half load and 3.71 gallons/hour at full load.

These are the separate fuel/load ratings in Generac specification A0005151077, Rev. D, August 13, 2026, page 4 (model listed on page 1). They illustrate this model only; they are not a range for all 22 kW generators or a prediction of your home’s varying load. Confirm the exact model revision, fuel, site conditions, and fuel-system capacity with your installer.

Fuel cost = consumption per hour × hours operated × local price per matching fuel unit. For a varying load, calculate each load period separately and add the costs. This estimates fuel only; maintenance, installation, and fixed utility charges are separate.

Use your current delivered propane price or utility tariff, including applicable usage-based delivery charges and taxes. Match gallons with price per gallon, or cubic feet with price per cubic foot. If gas is billed in therms, use the utility’s heat-content conversion before multiplying; cubic feet and therms are not interchangeable. No current fuel price or typical daily bill is assumed here.

Ask your propane supplier and installer to size the tank for the exact generator, expected load, desired outage duration, other connected appliances, and refill access. Nominal tank capacity is not all usable fuel: filling limits and the minimum operating level matter.

The system must also deliver enough propane vapor at the lowest expected temperature and fuel level, through correctly sized regulators and piping. Dividing nominal tank gallons by a generic burn rate cannot establish reliable runtime. We do not assign a universal duration to a tank size.

Before work begins, ask your local building department which electrical, fuel-piping, site, zoning, and inspection approvals apply to your address and proposed installation. Have the installer identify who will obtain any approvals and include their fees in the quote. This FAQ does not determine local requirements.

Compare the exact model’s published sound level together with its measurement distance, load or exercise mode, and measurement direction. A low-speed exercise rating is not the same test condition as operation under load. Ask the installer to review placement and applicable local noise rules.

Use the maintenance schedule for your exact model and serial number. Check both calendar and accumulated run-hour limits, follow whichever comes first where specified, and check for break-in, continuous-use, and severe-condition instructions. Do not substitute an annual service visit for inspections needed during an outage.

Ask the service provider to separate owner inspections from professional service and to itemize oil/filter, air-filter, spark-plug, and battery work applicable to your model. Perform only owner tasks you understand and can safely complete under the manual’s shutdown instructions; arrange qualified service for the rest. This page assumes no universal replacement interval or service price.

Follow the exercise settings in your model’s owner manual and controller. Confirm the schedule and duration with your installer, and check reported faults. Exercise options vary; an exercise run does not replace scheduled maintenance or establish fuel consumption while powering the house.

Get itemized local quotes for your site. Separate generator equipment, transfer equipment, electrical work, NG/LP supply work, pad/site preparation, any permit fees, optional upgrades, and unusual service or site conditions. Confirm what each quote includes.

Installation cost depends on the location and work required, so this page gives no national installed-price range. Use the generator sizing calculator as a planning starting point, then have the installer confirm equipment and site requirements before quoting.