GENMAX GM1200i review: our full analysis
Brand: GENMAX · Ranked 152nd of 174 · Our methodology
5.9/10 Power4.2 Runtime6.0 Noise9.2 Features6.3 Portability6.0 Watts per dollar4.8 Dotted line: average of the 174 models. Relative scores based on specs, no hands-on testing. Where to buy Today's best priceTypical price: under $300 Check best price Affiliate link: As an Amazon Associate we earn from qualifying purchases.Not clearly published by the manufacturer, take with caution: EPA compliance, CARB compliance.
Pros
- 1,000 running watts at 57 dB(A) at 23 ft and 25% load.
- 25.3 lb with a carry handle.
- Parallel-ready, with CO shutdown and dual USB ports.
Cons
- 0.7-gallon tank: 6.5 hours at half load.
- One 5-20R duplex only, no 30 A outlet.
- Recoil start only.
Best for
- Camping, tailgating and small jobs away from an outlet
- Places where noise matters: campgrounds, close neighbors
Specifications
| Type | Gas inverter (inverter: clean power) |
|---|---|
| Running watts | 1,000 W gasoline |
| Starting watts | 1,200 W gasoline |
| Fuel | Gasoline |
| Fuel tank | 0.7 gal |
| Runtime | 10 hours at 25% load · 6 hr 30 min at 50% load |
| Noise | 57 dB(A) (manufacturer figure) |
| Weight | 25.3 lb |
| Outlets | 2 × 120 V household outlets (5-20R) · USB ports |
| Transfer switch ready | No (no 240 V outlet) |
| Start | Recoil (pull start) |
| CO shutoff sensor | Yes |
| Parallel capable | Yes |
| Emissions | EPA compliant |
| Engine | 57 cc |
| Warranty | 3 years |
GENMAX GM1200i1,000 running W · Gas inverter · typical price under $300
Check price and availability
Who is it for?
The GENMAX GM1200i is mostly suited to:
- Camping, tailgating and small jobs away from an outlet.
- Places where noise matters: campgrounds, close neighbors.
Power output: running and starting watts
The GENMAX GM1200i delivers 1,000 W continuously and up to 1,200 W for a few seconds to start motors. It handles 4 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.
| Appliance | Running / starting watts | Will it run? |
|---|---|---|
| Wi-Fi router and modem | 20 W / 20 W | ✅ Yes |
| CPAP (no humidifier) | 50 W / 50 W | ✅ Yes |
| Laptop or TV | 150 W / 150 W | ✅ Yes |
| Full-size refrigerator | 700 W / 2,200 W | ❌ No |
| Chest freezer | 500 W / 1,500 W | ❌ No |
| Furnace blower (1/2 HP) | 800 W / 2,350 W | ❌ No |
| Sump pump (1/2 HP) | 1,050 W / 2,150 W | ❌ No |
| Microwave (1,000 W) | 1,000 W / 1,000 W | ✅ Yes |
| Space heater | 1,500 W / 1,500 W | ❌ No |
| Window AC (10,000 BTU) | 1,200 W / 3,600 W | ❌ No |
| RV roof AC (13,500 BTU) | 1,800 W / 2,800 W | ❌ No |
| Circular saw | 1,400 W / 2,300 W | ❌ No |
| Well pump (1 HP, 240 V) | 1,000 W / 4,000 W | ❌ Needs 240 V |
| Central AC (3-ton, soft start) | 3,800 W / 5,500 W | ❌ Needs 240 V |
Typical figures; check the label of your own appliances. One load at a time: add up everything you run together.
GENMAX GM1200i1,000 running W · Gas inverter · typical price under $300
Check best price
How long does it run on a tank?
The fuel tank holds 0.7 gallons of gasoline. The manufacturer quotes 10 hours at a quarter load. At half load, it runs about 6 hr 30 min on a full tank. That is about 0.11 gallon per hour at half load, or 3 gallons for a full day of running, so plan your fuel storage for a multi-day outage.
57 dB(A): how loud is it?
The manufacturer rates the GENMAX GM1200i at 57 dB(A), usually measured at 23 feet (7 m) and a light load. That is quieter than a normal conversation: suitable for campgrounds and close neighbors.
Outlets and home connection
Its panel offers 2 × 120 V household outlets (5-20R), USB ports. It has no 240 V outlet: it runs plug-in appliances through extension cords, not hardwired circuits or a 240 V well pump. It is parallel capable: linked to a second compatible unit with a parallel kit, the two outputs combine.
Starting, safety 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 under $300: good value per watt?
Relative to its running watts, the GENMAX GM1200i scores 4.8/10 on value: a high price per watt, which its other strengths may justify. 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 GM1200i1,000 running W · Gas inverter · typical price under $300
Check best price
Our verdict on the GENMAX GM1200i
The GENMAX GM1200i scores 5.9/10 and ranks 152nd out of 174 generators analyzed. Its strengths: 1,000 running watts at 57 dB(A) at 23 ft and 25% load; 25.3 lb with a carry handle. It is best suited to camping, tailgating and small jobs away from an outlet and places where noise matters: campgrounds, close neighbors.
GENMAX GM1200i1,000 running W · Gas inverter · typical price under $300
Check best price
Featured in our rankings
Sources
- Official GENMAX product page (specifications)
- Amazon.com listing (availability and typical price, November 2026)
Frequently asked questions
Will the GENMAX GM1200i run a refrigerator?
Not reliably: a full-size fridge can need about 2,200 W for a moment when the compressor starts.
Can the GENMAX GM1200i power a house?
Only plug-in appliances through extension cords: it has no 240 V outlet for a transfer switch.
How long does the GENMAX GM1200i run on a tank?
About 6 hr 30 min at half load according to the manufacturer, and 10 hours at a quarter load.
Does the GENMAX GM1200i run on propane?
No, it runs on gasoline only.
Is the GENMAX GM1200i quiet?
The manufacturer rates it at 57 dB(A), quiet enough for most campgrounds.
GENMAX GM1200i1,000 running W · Gas inverter · typical price under $300
Check best price
GENMAX GM1200i5.9/10 · under $300
Check best price
Other GENMAX generators
GENMAX · Tri fuel
GENMAX GM15000ET
11,000 W
76 dB(A)242 lbCO
$1,800–$2,500Read the review →
7.4
Tri fuel
GENMAX · Tri fuel inverter
GENMAX GM9000iET
8,000 W
62 dB(A)138 lbCO
$1,200–$1,800Read the review →
7.4
Tri fuel
GENMAX · Tri fuel inverter
GENMAX GM10500XiT
7,800 W
74 dB(A)124 lbCO
$1,200–$1,800Read the review →
7.4
Tri fuel
GENMAX · Tri fuel inverter
GENMAX GM17000iETC
13,500 W
63 dB(A)313 lbCO
Over $2,500Read the review →
Same price range, other brands
AIVOLT · Gas inverter
AIVOLT VO4200iX 4200W Open Frame Inverter
3,300 W
68 dB(A)54 lb
Under $300Read the review →
7.3
Best value
Genkins · Gas inverter
Genkins GK4500iF Lite 4500W Open Frame Inverter
3,700 W
70 dB(A)56 lb
Under $300Read the review →
7.2
Best value
Oxseryn · Gas inverter
Oxseryn EDOG10 4400W Open Frame Inverter
3,400 W
72 dB(A)56 lb
Under $300Read the review →