Guide
Updated · 24 Sep 2026 · Sheet checked · 24 Sep 2026
It depends
For homeowners sizing a portable inverter for roughly 72 hours of ice-storm outage — fridge, communications, blower heat — and choosing dual-fuel (gasoline + propane) versus a gasoline-only fuel plan.
Compare guide, not a SKU. Running watts first, surge second. Desk math from manufacturer tables and DOE AFDC. Cross-check /guides/what-size and /guides/fridge-modem-furnace-8-hours.
Fuel choice for a three-day ice storm: cold starts, staged fuel when stations are shut, and continuous watts after propane derate. Anchors: Champion 201531, Champion 201532, DuroMax XP11000iH, plus DOE AFDC.
Not whole-home standby with a listed ATS — that is Generac Guardian 22 kW class.
Measure first. On the same dual-fuel carton, propane continuous watts are lower than gasoline. Surge is often the same badge; continuous keeps fridge and blower online.
| Live dual-fuel example | Gas run / surge | Propane run / surge | Mfr runtime @ ~25% load |
|---|---|---|---|
| Champion 201531 | 3,250 W / 4,500 W | 2,925 W / 4,500 W | Up to 10 h on 1.54 gal gas; up to 25 h on a 20 lb propane cylinder |
| Champion 201532 | 5,250 W / 6,500 W | 4,725 W / 6,500 W | Specs: up to 18 h gas (4.5 gal); up to 16 h on a 20 lb propane cylinder |
Quarter-load hours are manufacturer points, not a 72-hour guarantee. A lean overnight stack (~200–400 W) sits under these ratings on either fuel; a PSC blower + fridge on can press propane’s lower ceiling on the 201531 class.
Energy density: DOE AFDC — 1 gal propane ≈ 73% of 1 GGE; LHV ≈ 112k–116k Btu/gal gasoline vs 84,250 Btu/gal propane. Charts trade watts and tank geometry, not free energy.
72-hour ice-storm logistics:
Stations alone fail 72 hours on Wh. Usable Wh ≈ rated × 0.85. Worked 500 W line: DELTA 2 (~1,024 Wh → ≈870 usable) ≈ 1.7 h; AC200L (~2,048 Wh → ≈1,741 usable) ≈ 3.4 h.
default. Street prices: not published here.Skip gasoline-only with stale ethanol cans and no propane path. Skip one 20 lb cylinder as a three-day sole plan. Skip a ~1–2 kWh station as a 72-hour plant. Skip treating propane continuous watts as equal to the gasoline badge. Skip indoor generator operation.
It depends. For a ~three-day Midwest ice storm, dual-fuel usually wins on fuel logistics and shelf life: propane sits ready without carb gum, and you can pre-stage cylinders when pumps are unreachable. Expect lower continuous watts on propane and plan frost / vapor-rate limits from the OM. Gasoline-only works if you rotate fresh fuel and need sits near the gasoline rating. Until load, inventory, and refill risk are known — It depends, not Buy.