Generac 8917 GP18000EFI 18,000-Watt Gas-Powered Electric-Start Portable Generator with Cosense & EFI Engine, Transfer Switch Compatible

From emergency home backup to DIY projects to the jobsite, the Generac GP18000EFI portable generator provides high wattage, dependable portable power. Equipped with an 816cc engine with Electronic Fuel Injection, the GP18000EFI delivers power efficiently, providing as much as 9 hours of runtime at 50% load. TruePower™ Technology safely powers sensitive electronics, appliances and tools whilst onboard COsense® Technology provides powerful protection against hazardous carbon monoxide. The GP18000EFI also features electric start (battery included), low-oil shutdown protection, circuit breaker secure outlets and an hour meter with maintenance resets. The included never-flat wheel kit and to be had lifting eye accessory make transportation easy around the home or jobsite.

COsense Technoology – Stops. Alerts. Saves. Powerful protection against hazardous carbon monoxide
Generac 816cc EFI Engine – Delivers the correct quantity of power to get the most productive performance and efficiency out of your engine
TruePower Technology – With lower than 5% THD, safely powers sensitive electronics and tools
Low-Oil Pressure Shutdown – Routinely safeguards engine from damage
Large Capacity Fuel Tank – With incorporated fuel gauge, provides durability and extended run times
Homelink Manual Transfer Switch Compatible – When paired with a manual transfer switch, the GP18000EFI is powerful enough to offer whole home backup and is a brilliant alternative to a Home Standby Generator.
Hardened 1 ¼” Steel Tube Cradle – For added strength and durability
Hour Meter – Tracks maintenance intervals
Heavy-Duty, Never-Flat Wheels – For reliable portability
Electric Start – Battery Included – Provides hassle-free start-up

4.5Expert Score

Generac GP18000EFI Review — Extreme Power, EFI Efficiency & Built-in Safety

The Generac GP18000EFI is one of the most powerful portable generators available, designed for serious backup needs or heavy-duty jobsite use. Delivering 18,000 starting watts and 14,000 running watts, it can keep nearly an entire home running or power multiple commercial-grade tools at once. Its EFI (Electronic Fuel Injection) engine improves efficiency, ensures smooth startups in all weather, and reduces maintenance compared to traditional carburetors. Generac includes its COsense technology for added safety, automatically shutting down the unit if carbon monoxide levels rise. The generator is also transfer switch compatible, making it easier to tie into home electrical systems for reliable backup. At over 400 pounds, it’s far from portable in the casual sense, and its noise and fuel consumption are substantial. Still, for those who need maximum wattage with modern safety and efficiency, the GP18000EFI stands out as one of the best in its class.

Power / Performance

5

Fuel Efficiency & Technology (EFI)

4.6

Safety Features (COsense)

4.7

Portability / Ease of Use

3.2

Value for Money

4

PROS

• Massive 18,000 starting watts / 14,000 running watts
• EFI engine = easier starts, better fuel economy, lower emissions
• COsense technology for carbon monoxide safety
• Transfer switch compatible for home backup integration
• Heavy-duty build with trusted Generac brand reputation

CONS

• Extremely heavy and difficult to transport (over 400 lbs)
• Loud operation (open-frame, high power)
• High fuel consumption under load
• Premium price point compared to smaller dual-fuel options