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A dark house during an outage makes the question urgent, and how much does a portable generator cost depends on what you ask it to run. A small inverter unit for a phone and a light costs far less than a tri-fuel unit that backs up a whole home, and the gap comes from watts, fuel type, inverter tech and features, not from the brand name alone. The steps below show how to work out what you need, so you can judge any listing on its figures.
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The quick answer
The price follows the watts. A 1750W AIVOLT inverter generator (on Amazon) weighs 26.5 pounds and runs up to 7 hours at 25 percent load, while a 12000W Westinghouse tri-fuel inverter generator weighs 191.0 pounds and runs up to 19 hours at 25 percent load on a 7.9 gallon tank. Between them sit dual-fuel units such as the 3600W WEN at 49.0 pounds and the 6800W WEN at 99.2 pounds. More watts, more fuel options, quieter running and longer warranties all push the price up, so the first step is to add up the watts your loads need. See how a portable generator works for the path from fuel to outlets.
Step 1: Add up the watts you need
Start with running watts, then check surge. The WEN 3600W dual fuel unit lists 3600 surge watts and 2900 rated watts on gasoline, and 3500 surge watts and 2600 rated watts on propane. The Westinghouse 8200W tri-fuel unit lists 6600 running and 8200 peak watts on gasoline, 5940 running and 7380 peak watts on propane, and 5280 running and 6560 peak watts on natural gas. A fridge, a sump pump and an air conditioner need surge headroom, and the listing’s surge figure is the one to compare. Use the emergency generator size calculator to work out your own loads.
| Unit | Peak watts | Weight | Runtime at 25 percent load |
|---|---|---|---|
| AIVOLT 1750W | 1750 | 26.5 pounds | 7 hours |
| Oxseryn 2800W | 2800 | 40.0 pounds | 9 hours |
| WEN 3600W | 3600 | 49.0 pounds | Not stated |
| Oxseryn 4400W | 4400 | 56.0 pounds | 14 hours |
| Westinghouse 8200W | 8200 | 134.5 pounds | 17 hours |
| Westinghouse 12000W | 12000 | 191.0 pounds | 19 hours |
The table shows the ladder: peak watts climb from 1750 to 12000, weight climbs from 26.5 pounds to 191.0 pounds, and runtime at 25 percent load climbs from 7 hours to 19 hours. Each step up the ladder costs more, so buy the watts you need and no more.
Step 2: Pick the fuel type
Gasoline is the baseline. Dual-fuel units add propane: the WEN 3600W runs on gasoline and propane, with 3600 surge watts on gasoline and 3500 surge watts on propane. Tri-fuel units add natural gas: the Westinghouse 8200W lists 6600 running watts on gasoline, 5940 on propane and 5280 on natural gas, so output falls as you move from gasoline to propane to natural gas. Fuel type moves the price because a tri-fuel unit needs extra regulators and fittings: the Westinghouse 12000W listing includes a propane regulator kit, oil, funnel and tool kit out of the box. See what a tri-fuel generator is and inverter versus dual-fuel generators for the trade-offs.
One more fuel note: the Oxseryn 2800W (on Amazon) listing warns that above 4000 feet, about 1200 meters, the generator may run rough without a high-altitude kit, and to switch back to the standard jet when returning to low-altitude areas.
Step 3: Weigh inverter tech and noise
An inverter adjusts engine speed to the load, which the Westinghouse 8200W listing says cuts fuel use and noise, with around 60 dBA at 25 percent load. The AIVOLT lists 52 dBA, the Oxseryn 2800W lists under 58 dBA from 23 feet away, and the PowerSmart lists 59 dBA from 23 feet away. The Westinghouse 12000W lists as low as 64 dBA, and the Oxseryn 4400W lists under 72 dBA from 23 feet away. Quieter running costs more, and the listing’s dBA figure is the one to compare, at the same load and distance. The Westinghouse 12000W listing says inverter tech can save up to 50 percent in fuel costs, which is part of what you pay for. See the benefits of an inverter generator for the full list.
Step 4: Check the outlets, safety and warranty
Outlets decide what you can plug in. The Westinghouse 8200W lists a 120/240V 50A outlet, a 120V 30A RV outlet and a 120V 20A duplex outlet, plus a CO sensor and automatic low oil shutdown. The WEN 6800W lists a 240V configuration for Level 2 charging of battery and hybrid electric vehicles, with onboard wheels and a telescoping pull handle. The WEN 3600W and 4800W list a CO Watchdog sensor that shuts the unit off when carbon monoxide is detected, and a three-year warranty. Warranty terms in the listings run from 1 year on the Oxseryn units to 2 years on the AIVOLT and PowerSmart, and 3 years on the Westinghouse and WEN units. Longer warranties and CO sensors add cost, and both are worth weighing against the price. Read the portable generator safety tips before your first run.
What pushes the price up
Bigger engines cost more: the listings run from a 79.8CC engine on the Oxseryn 2800W to a 457cc engine on the Westinghouse 12000W. Electric start, remote start, wheels, a pull handle and a digital display all add cost: the WEN 6800W lists electric start with onboard wheels and a telescoping pull handle, and the Westinghouse 12000W lists a remote start key fob and a digital display that shows fuel level, power output, remaining run time and voltage output. Clean power under 3 percent THD costs more too, and the PowerSmart and AIVOLT listings say it is safe for laptops, phones and tablets. A unit with a 2 gallon tank runs longer than one with a 0.66 gallon tank, and the Westinghouse 12000W lists a 7.9 gallon tank with up to 19 hours at 25 percent load.
How much does a portable generator cost: the short version
Work out your running watts and your surge watts, pick the fuel type, then compare listings at that size. A 1750W unit at 26.5 pounds suits camping and a few small loads, a 3600W or 4400W unit suits an RV and a fridge, and an 8200W or 12000W tri-fuel unit suits home backup. The price follows that ladder, with quieter running, more fuel options, more outlets and longer warranties each adding cost. For the wider choice, see what the best portable generator is.
FAQ: power away from the grid
What size portable generator do I need?
Add up the running watts of everything you want to run at once, then check the surge figure. The WEN 3600W lists 3600 surge watts and 2900 rated watts, and the Westinghouse 8200W lists 6600 running and 8200 peak watts on gasoline. Pick a unit whose running watts cover your loads and whose surge watts cover the biggest motor starting.
Is an inverter generator worth the extra cost?
An inverter adjusts engine speed to the load, which the Westinghouse 8200W listing says cuts fuel use and noise, at around 60 dBA at 25 percent load. Inverter units also list clean power under 3 percent THD, which the PowerSmart and AIVOLT listings say is safe for laptops, phones and tablets.
How long will a portable generator run on a tank?
The listings here run from 7 hours on the AIVOLT with a 0.66 gallon tank to 19 hours on the Westinghouse 12000W with a 7.9 gallon tank, all at 25 percent load. Bigger tanks and lower loads run longer, and the listing’s runtime figure is the one to compare.
Do portable generators work on propane or natural gas?
Dual-fuel units run on gasoline and propane, and tri-fuel units add natural gas. The Westinghouse 8200W lists 6600 running watts on gasoline, 5940 on propane and 5280 on natural gas, so output falls as you move across fuels.
