Generac 18 kW Home Standby Generator

A Generac 18 kW generator is a permanently installed home standby generator sized to keep most of a house running when the utility power drops. This air-cooled standby generator sits outside on a pad, runs on natural gas or propane, and starts on its own within seconds of an outage, so your family is not left waiting through a Southeastern storm or a strained-grid blackout.

Anderson Power Services sells, installs, and maintains this backup generator as a local, veteran-founded authorized Generac dealer. Our factory-trained technicians handle the set, the fuel connection, and the transfer switch wiring, and our team stays on for maintenance and monitoring after startup.If you are comparing sizes across Generac generators, our team can confirm whether the 18kW or another unit is right for your house during a free consultation.

The Generac 18 kW at a Glance

The 18kW air-cooled standby generator is built around Generac’s G-Force 800 Series engine and the Power Zone 200 controller, and bundled versions ship with a service-rated automatic transfer switch. Key specifications from the manufacturer:

• Power output: 18 kW on liquid propane, 17 kW on natural gas
• Fuel: natural gas or liquid propane. The unit draws fuel automatically from your gas line or propane tank, so there are no gas cans to fill or extension cords to run during an outage.
• Power quality: 240V single-phase with less than 5% total harmonic distortion, Generac’s True Power technology, for sensitive electronics
• Engine: Generac’s G-Force 800 Series, a two-cylinder 817 cc pressure-lubricated engine with electronic fuel and ignition control and an oil level sensor
• Transfer switch: 200-amp service-rated automatic transfer switch included with bundled models
• Remote monitoring: Mobile Link cellular standard, with Wi-Fi and Bluetooth
• Enclosure: sound-attenuated, corrosion-resistant aluminum, rated to withstand winds up to 150 mph
• Sound level: about 65 dB(A) at 23 feet under normal load and 55 dB(A) during the weekly Quiet-Test self-test
• Footprint: roughly 46 by 26 inches, and it can sit as close as 18 inches to the house where local codes allow
• Warranty: 5-year limited warranty covering the generator and the transfer switch

The G-Force engine is built for long run times, and full-pressure lubrication supports a service interval of up to two years or 200 hours between oil changes. True Power technology holds total harmonic distortion under 5%, which is what lets the 18 kW run variable-speed HVAC and other sensitive electronics cleanly rather than only powering basic circuits.

How the 18 kW Home Standby Generator Works

The 18 kW connects to your main electrical panel through an automatic transfer switch and draws fuel from your natural gas line or a propane tank, so there is nothing to refuel and no cord to run. The transfer switch monitors your utility feed, and when it detects a loss of power, it disconnects the house from the grid and signals the generator to start, restoring backup power at your panel within seconds.

When utility service returns, the transfer switch moves the house back to the grid and shuts the generator down, with no action needed from you. Because it wires into the main panel, a right-sized 18kW standby generator can carry your air conditioning, heat, water heater, refrigerator, and the priority circuits your household depends on rather than a handful of outlets. Because it sits outside and vents away from the house, it keeps exhaust out of your living space.

Is the 18 kW Right for Your Home

The 18 kW sits toward the upper end of the air-cooled lineup, which makes it a common fit for mid-sized and larger homes that want a whole-home generator or for a big all-electric home where a few managed loads keep the rest running. What it can cover depends on your square footage, the size of your air conditioning, and whether your heat is gas or electric.

Sizing is the part worth getting right, since a unit that is too small leaves you short during an outage and one that is larger than you need costs more up front. A free on-site consultation is where our factory-trained technician reviews your panel and your priority loads and confirms whether the 18kW is the correct whole-house generator for you or whether a different size delivers the standby power you need.

What Installation Looks Like

Generator installation ties into both your gas and electrical systems and has to meet local code, so it is work for licensed professionals. Anderson Power Services handles the full installation, including the transfer switch installation, and once permitting clears, most home installs take only a few days on site. The project runs in four steps:

1. Free on-site consultation: we review your electrical panel and main breaker and size the system to your home.
2. Permitting: we handle the required permits and coordinate the inspection.
3. Installation: we set the pad and the unit, connect the natural gas or propane supply, and wire the transfer switch into your panel.
4. Startup: we commission the generator, run a transfer test, and walk you through how it operates.

Keeping Your 18kW Ready

A home backup generator earns its cost on the one day you need it, so it has to be maintained to be reliable. Each week the 18 kW runs a brief self-test in a quieter, lower rpm mode that uses less fuel while it checks that the unit is in top operating condition. Its long service interval and pressure-lubricated engine keep routine maintenance light, and in colder climates Generac offers cold-weather accessories like a battery and oil heater to help the unit start in freezing conditions.

The Mobile Link connection lets you monitor the generator from the Mobile Link app on a phone, tablet, or computer, with real-time operating status, maintenance alerts, battery status, and local weather conditions in one place. It also tracks maintenance intervals and confirms generator readiness, so you know the unit is ready before the next power outage. Anderson backs the 18kW with maintenance and service plans that include 24/7 remote monitoring, so it is tested on a schedule and watched year-round.

Generac 18kW Generator FAQs

What can a Generac 18 kW generator power in a home?
On propane, the unit delivers 18 kW, and on natural gas, 17 kW, which is enough for many homes to run air conditioning, heat, a water heater, the kitchen, and daily-use circuits together. In a larger house, pairing the 18kW standby generator with load management keeps the systems that matter most online. We confirm exactly what it will carry when we size it for your home.

Is an 18 kW big enough for my house, or do I need something larger?
For a lot of mid-sized and larger homes, the 18 kW works as a whole-house generator, and for a big all-electric home, it can protect priority circuits while managing the rest. The right answer depends on your square footage, air conditioning, and heating type, which is why our technician sizes it during the free consultation rather than guessing from a chart.

Does the 18 kW run on natural gas or propane, and how much fuel does it use?
Its dual fuel capability means it runs on either. On natural gas, it draws roughly 164 cubic feet per hour at half load and 235 at full load, and on propane, about 1.65 gallons per hour at half load and 2.87 at full load. A natural gas unit runs as long as the line supplies fuel, while a liquid propane unit’s run time depends on tank size.

Does the Generac 18 kW come with a transfer switch?
Bundled models include a 200-amp service-rated automatic transfer switch, which is the component that senses the outage, starts the generator, and moves your home between grid and generator power automatically. We handle the transfer switch installation and wire it into your main panel as part of the job.

How loud is the 18 kW when it runs?
It’s quiet enough to hold a conversation next to. For the specifics, it produces about 65 dB(A) measured at 23 feet under normal load and drops to around 55 dB(A) during its weekly self-test, which runs the engine at a lower rpm and uses less fuel. The sound-attenuated, corrosion-resistant aluminum enclosure is a large part of why this standby generator stays that quiet.

Can I check on the 18kW from my phone?
Yes. Mobile Link cellular monitoring is standard, with Wi-Fi and Bluetooth as well, so the Mobile Link app shows real-time operating status, maintenance alerts, battery status, and generator readiness from a smartphone, tablet, or computer. You can also connect your account to Anderson for proactive customer support.

What warranty comes with the Generac 18kW?
The unit carries a 5-year limited warranty that covers both the generator and the transfer switch. Keeping up with the manufacturer’s maintenance schedule is what keeps that coverage in force, and our service plans are built to do exactly that.

Be Sure You Have Power When You Need It Most

The 18kW is a lot of standby power, but the right size for your home is a conversation, not a guess. Book a free on-site consultation and our team will size the system, walk you through this Generac home standby generator, and lay out installation and financing built around your home. For local customer support and peace of mind that the unit will start when you need it, call 706-348-1501 or reach out online to get started.