Outage & off-grid scenarios
Most generator questions aren’t about one appliance — they’re about a situation: the storm that takes the power out, the winter outage with a furnace to run, the weekend away from hookups. Each scenario below is a pre-loaded build in the same calculator used across this site, with every addition explained: which running watts add up, which single starting surge counts, and which size class the total honestly lands in. Open one and adjust it to match your home.
Pick your situation
Storm backup essentials
The classic outage set — fridge, chest freezer, TV/Wi-Fi/lights — added up correctly: 1,450W running, 2,950W peak with staggered starts, 3,688W with headroom.
Open scenario →Home essentials + well pump
Fridge, electronics and a 1/2 HP well pump on one generator: 1,950W running, 3,450W peak, 4,313W with headroom — and the 240V requirement that decides everything.
Open scenario →Home essentials + sump pump
Fridge, freezer, electronics and a 1/3 HP sump pump on one generator: 2,250W running, 3,750W peak, 4,688W with headroom — just over the 4,500W class line.
Open scenario →Essentials + furnace in winter
The ice-storm build — gas furnace blower, fridge, TV/Wi-Fi/lights: 1,650W running, 3,150W peak, 3,938W with headroom. Whole-house heat from a mid-size portable.
Open scenario →Whole house with central AC
Whole-house backup with 3-ton central AC, honestly computed: 5,650W running, 13,050W peak, 16,313W with headroom — why this build means a standby unit and an electrician.
Open scenario →RV weekend setup
The boondocking weekend build — 13,500 BTU roof AC plus camp essentials: 1,700W running, 3,200W peak, 4,000W with headroom. One portable or two paralleled inverters.
Open scenario →
How scenario math works
Running watts add across everything selected. Starting surges do not: with loads plugged in one at a time — largest motor last — only the single biggest starting delta lands on top of the running total. We then apply 25% headroom and map the result to standard generator size classes. If any load needs 240V, the scenario says so prominently, because that requirement filters generators before wattage does. The full model, its assumptions and its limits are on the methodology page; every underlying figure is sourced on the appliance pages and should be checked against your own nameplates.