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FIRMAN WT03571

Ranked #18 of 30 in Best Portable Inverter Generators: Champion, Westinghouse, WEN, DuroMax & FIRMAN (2026). Here is every spec we scored, where it came from, and how it compares.

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F

#18

FIRMAN WT03571

Best for: Tri-fuel inverter at 52 lb

5.2/10

What we like

Watch out for

Runtime at 50% load not published by Firman

Score breakdown

Running watts (gasoline) 25%

Runtime at 25% load 15%

Runtime at 50% load * 5%

Noise 15%

Weight 10%

CO shutoff 10%

Runs on propane 10%

CARB compliant * 5%

Parallel capable 5%

* Not published by the manufacturer; scored at the lowest published value in this category, so an unpublished figure never outranks a published one.

* Other unpublished figures are scored at the category median so missing data neither helps nor hurts.

Running watts (gasoline)	3500 W
Runtime at 25% load	8 h
Runtime at 50% load	Not listed
Noise	64 dBA
Weight	52 lb
CO shutoff	Yes
Runs on propane	Yes
CARB compliant	Not listed
Parallel capable	Yes
Starting (peak) watts, gasoline	4,400 W
Running watts on propane	3,200 W
Running watts on natural gas	2,800 W
Fuel tank	1.6 gal
Outlets	Not published by the maker
Noise basis	64 dB as listed
CO shutoff	FIRMAN CO Alert
CARB	Not published by the maker
Price	Check price

Check price at Amazon

Specs source:

FIRMAN: WT03571

How it compares

Open the full comparison table

Westinghouse iGen5000DFc

#1 · EFI dual fuel with 18 h at quarter load and 52 dBA

Champion 6500W Dual Fuel Inverter (201532)

#2 · Most running watts here on a 64 dBA rating, with an L14-30R

DuroMax XP7000iH

#3 · 5,500 W dual fuel inverter with an L14-30R

Westinghouse iGen2550DFc

#4 · Small dual fuel with a TT-30R RV outlet

Westinghouse iGen4000DFc

#5 · Dual fuel 3,300 W at 52 dBA

Champion 4500W Electric Start Dual Fuel Inverter (201319)

#6 · 3,500 W dual fuel with 14 h at quarter load

WEN DF500iX

#7 · 120/240V dual fuel with 9 h at half load

Champion 2000W Dual Fuel Inverter (201230)

#8 · 2,000 W dual fuel with CO Shield at 39.5 lb

Champion 2500W Dual Fuel Inverter (201323)

#9 · Small dual fuel inverter at 53 dBA

DuroMax XP2300iH

#10 · Small dual fuel inverter at 52 dB

FIRMAN WH03342

#11 · Whisper dual fuel at 58 dB

WEN DF680iX

#12 · 5,100 W dual fuel with an L14-30R

Champion 5500W Dual Fuel Inverter (201561)

#13 · 4,000 W dual fuel with CO Shield and an RV outlet

Champion 4500W Dual Fuel Inverter (201531)

#14 · Light 4,500 W-peak dual fuel at 51.8 lb

WEN DF480iX

#15 · 4,000 W dual fuel with 7 h at half load

WEN DF525iX

#16 · Same 4,200 W on gas or propane

Champion 4000W Dual Fuel Inverter (201050)

#17 · 3,000 W dual fuel inverter at 51.8 lb

WEN DF280iX

#19 · 2,250 W dual fuel with 9 h at half load

Westinghouse iGen2550c

#20 · 1,900 W, 40 lb, TT-30R

Westinghouse iGen2800c

#21 · 2,200 W at 52 dBA with 12 h at quarter load

Westinghouse iGen4000c

#22 · Gas 3,300 W with remote start and 52 dBA

WEN DF360iX

#23 · 2,900 W dual fuel at 49 lb

Westinghouse iGen1500c

#24 · Smallest here: 1,000 W at 32 lb

Champion 5500W Inverter (201560)

#25 · 4,000 W gas-only inverter at 73.4 lb

WEN 56432iX

#26 · 3,600 W gas inverter at 53 lb

Champion 3400W Electric Start Dual Fuel Inverter (100396)

#27 · 3,100 W dual fuel with an L5-30R

Champion 2500W Inverter (201490)

#28 · Lightest generator here at 37.7 lb

Champion 4500W Inverter (201318)

#29 · 3,500 W gas inverter with 14 h at quarter load

WEN 56250iX

#30 · Light 1,900 W gas inverter at 37.5 lb