GENMAX GM4500iSAD review: our full analysis

4,000 running watts: what can it power?

The GENMAX GM4500iSAD delivers 4,000 W continuously and up to 4,500 W for a few seconds to start motors on gasoline. On propane, the manufacturer rates it at 3,600 running watts (4,000 W starting), 10% less. It handles 12 of the 14 loads on our typical list one at a time; add up the running watts of everything you run together, plus the extra starting watts of the biggest motor. As an inverter, it produces clean power suited to laptops, TVs and furnace control boards.

Typical figures; check the label of your own appliances. One load at a time: add up everything you run together.

GENMAX GM4500iSAD4,000 running W · Dual fuel inverter · typical price $500–$800 Check best price

How long does it run on a tank?

The fuel tank holds 0.9 gallons of gasoline. The manufacturer quotes 4 hr 50 min at a quarter load. At half load, count on roughly 3 hr (our estimate from the quarter-load figure). That is about 0.30 gallon per hour at half load, or 7 gallons for a full day of running, so plan your fuel storage for a multi-day outage. On propane, a standard 20 lb tank holds about 4.7 gallons of LP; propane does not go stale, which makes it the easiest fuel to stock.

62 dB(A): how loud is it?

The manufacturer rates the GENMAX GM4500iSAD at 62 dB(A), usually measured at 23 feet (7 m) and a light load. That is about the level of a conversation or a dishwasher: acceptable at a campground.

Outlets: home, RV and tools

Its panel offers 2 × 120 V household outlets (5-20R), TT-30R 30 A RV outlet, 12 V DC outlet. It has no 240 V outlet: it runs plug-in appliances through extension cords, not hardwired circuits or a 240 V well pump. The TT-30R outlet plugs straight into a 30 A RV. It is parallel capable: linked to a second compatible unit with a parallel kit, the two outputs combine.

Start type, CO shutoff and warranty

It starts with a recoil (pull) cord. A CO shutoff sensor stops the engine if carbon monoxide builds up around it; it does not replace distance (20 feet from the house) and CO alarms indoors. It is listed as EPA compliant; check California availability if you live there. The warranty runs 3 years (residential use).

Typical price $500–$800: good value per watt?

Relative to its running watts, the GENMAX GM4500iSAD scores 7.2/10 on value: an average result. Inverters always cost more per watt than open frames: compare it with other inverters. Generator prices on Amazon move a lot, especially before hurricane season: check the current price before you buy.

GENMAX GM4500iSAD4,000 running W · Dual fuel inverter · typical price $500–$800 Check best price