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FIRMAN WT12579

Ranked #10 of 23 in Best Home Standby & Large Portable Generators: Champion, Westinghouse, DuroMax & FIRMAN (2026). Here is every spec we scored, where it came from, and how it compares.

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#10

FIRMAN WT12579

Best for: 10,000 W tri-fuel inverter at 69 dB

4.9/10

What we like

    Watch out for

    • Runtime at 50% load (gasoline) not published by Firman

    Score breakdown

    Running watts (best listed fuel) 35%
    Noise 15%
    Runs on natural gas 15%
    Runtime at 50% load (gasoline) * 10%
    Transfer switch / transfer-switch ready 10%
    CO shutoff 10%
    CARB compliant * 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    * Not published by the manufacturer; scored at the lowest published value in this category, so an unpublished figure never outranks a published one.

    * Other unpublished figures are scored at the category median so missing data neither helps nor hurts.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 (best listed fuel)10000 W
    Noise69 dBA
    Runs on natural gasYes
    Runtime at 50% load (gasoline)Not listed
    Transfer switch / transfer-switch readyYes
    CO shutoffYes
    CARB compliantNot listed
    Starting (peak) watts, gasoline12,500 W
    Running watts on propane9,000 W
    Running watts on natural gas7,500 W
    Fuel tank7.1 gal
    OutletsIncludes 120/240V L14-30R
    Noise basis69 dB at 25% load
    CO shutoffFIRMAN CO Alert
    CARBNot published by the maker
    PriceCheck price
    Check price at Amazon
    Specs source:

    FIRMAN WT12579 head-to-head

    Head-to-headFIRMAN WT12579 vs Westinghouse iGen12000DFc Featured inBest Natural-Gas Backup Generators (2026)

    How it compares

    Open the full comparison table

    Champion 26 kW Whole House Home Standby Generator and 200A Switch with fleX Technology (201614)
    8.1/10
    #1 · Largest output here: 26 kW on propane
    Champion 22 kW Whole House Home Standby Generator and 200A Switch with aXis Technology (201221)
    7.4/10
    #2 · 22 kW whole-house kit with a 200A switch (aXis)
    Champion 22 kW Whole House Home Standby Generator and 200A Switch with fleX Technology (201016)
    7.4/10
    #3 · 22 kW whole-house kit with a 200A switch (fleX)
    Champion 18 kW Whole House Home Standby Generator and 200A Switch with fleX Technology (201566)
    6.6/10
    #4 · 18 kW whole-house kit at 67 dB(A)
    Champion 14 kW Whole House Home Standby Generator and 200A Switch with aXis Technology (100839)
    6.1/10
    #5 · 14 kW whole-house kit at 62 dB(A)
    Champion 12.5 kW Select Circuit Home Standby Generator and 100A Switch 10 Year Warran (100179)
    5.7/10
    #6 · 12.5 kW select-circuit kit at 63 dB(A)
    Champion 10 kW Whole House Home Standby Generator and 200A Switch with fleX Technology (201597)
    5.3/10
    #7 · 10 kW whole-house kit at 61 dB(A)
    Champion 13,500W Electric Start Tri Fuel Generator (201241)
    5.1/10
    #8 · 13,500 W tri fuel with CO Shield
    Champion 8.5 kW Select Circuit Home Standby Generator and 50A Switch (100177)
    5.1/10
    #9 · Quietest here: 8.5 kW select-circuit kit at 59.5 dB(A)
    DuroMax XP13000HXT
    4.8/10
    #11 · Tri fuel 10,500 W with CO alert
    Westinghouse WGen20000c
    4.8/10
    #12 · Most portable output here: 20,000 W with CO sensor
    Champion 10,000W Electric Start Tri Fuel Generator (201438)
    4.7/10
    #13 · 10,000 W tri fuel with 14-50R
    FIRMAN T09376
    4.6/10
    #14 · 9,200 W tri fuel with 11 h at half load
    DuroMax XP15000HX
    3.8/10
    #15 · 12,000 W dual fuel with CO alert
    Westinghouse WGen14500DFc
    3.8/10
    #16 · 14,500 W dual fuel with CO sensor
    DuroMax DS14000iX
    3.6/10
    #17 · 11,000 W open-frame inverter with 23.3 h at quarter load
    Champion 11,000W Electric Start Dual Fuel Inverter (201417)
    3.5/10
    #18 · 9,000 W dual-fuel inverter at 64 dB(A)
    DuroMax XP13000EH
    3.3/10
    #19 · 10,500 W dual fuel with CO alert
    Champion 11,000W Wireless Start Dual Fuel Generator (201544)
    3.3/10
    #20 · 11,000 W dual fuel with wireless start
    Westinghouse iGen12000DFc
    3.1/10
    #21 · 9,000 W dual-fuel inverter, 19 h at quarter load
    DuroMax XP11000iH
    2.8/10
    #22 · 9,000 W dual-fuel inverter
    Westinghouse ecoGen10000
    2.6/10
    #23 · 7,600 W inverter with 14-50R and L14-30R