What it puts out
Generac rates it at 18,000 watts on propane and 17,000 watts on natural gas: 1,000 watts less on natural gas. If your home is on natural gas, size from the natural gas figure.
Generac Guardian 18kW home standby
Generac 18kW generator installed in San Antonio
Generac rates the Generac Guardian 18kW at 18,000 watts on propane and 17,000 watts on natural gas. Whether that carries your house depends on your load list, which a free sizing visit settles.
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The 18kW in plain terms
Does a Generac 18kW generator put out less on natural gas?
Yes, by 1,000 watts. Generac rates the 18kW at 18,000 watts on propane and 17,000 watts on natural gas, so a home on natural gas should size from the natural gas figure. That is 3,000 watts more on natural gas than the 14kW below it and 2,500 watts less than the 22kW above it.
What it can run
A 18kW unit carries the loads that fit inside its rating at the same time, including the extra current a central air conditioner draws as it starts. Only your load list can say whether that is the whole house or a set of essential circuits.
- Your air conditioning and how it starts
- The refrigerator, freezer and well or sump pump
- Medical equipment and the home office
Compared with the sizes beside it
The 14kW below it is rated 14,000 watts on natural gas, 3,000 watts less. The 22kW above it is rated 19,500 watts on natural gas, 2,500 watts more.
Transfer switch
The unit needs a transfer switch matched to your service and to the loads you choose: whole house, essential circuits, or load management for large air conditioning loads.
Installation
We set the unit, install and wire the transfer switch, pull the electrical permit and start it up under load. Gas line and gas connection are not included. That is a licensed plumber's work and we quote it separately.
Cost
The installed price for a 18kW is the unit plus the switch, the electrical work, the gas line, placement and the permit. We write yours after the free sizing visit.
Questions about generac 18kw generator installation? Call or get a quote.
From Generac's published specifications
What are the Generac 18kW generator's specifications?
Generac's published figures list the Guardian 18kW, base model G007226, at 18,000 watts on propane and 17,000 watts on natural gas. It runs a G-Force 800 engine, carries an 80 amp main line circuit breaker and weighs 420 lb. Generac publishes a 5 Year Limited Warranty, and its specifications are subject to change without notice.
| Generac base model | G007226 |
|---|---|
| Rated power, propane | 18,000 watts |
| Rated power, natural gas | 17,000 watts |
| Engine | G-Force 800 |
| Main line circuit breaker | 80 amps |
| Weight | 420 lb |
| Warranty, as Generac publishes it | 5 Year Limited Warranty |
Figures as Generac published them on 2026-10-31. Generac notes that specifications are subject to change without notice, and the written warranty terms for the exact model are Generac's. Source: Generac's 18kW product page and its spec sheet.
Questions about generac 18kw generator installation? Call or get a quote.
Generac quote
Is the Generac 18kW right for my house?
Leave your name and number. We set the free sizing visit and tell you plainly which size fits.
Prefer to talk? Call (210) 446-5446.
FAQ
What do people ask about the Generac 18kW generator?
Straight answers. If you do not see yours, call us and ask.
Generac rates it at 18,000 watts on propane and 17,000 watts on natural gas.