Every generator decision eventually collapses into one question: what will X watts actually run in my house? The marketing answer is a cheerful icon strip (fridge! TV! AC!) that ignores the arithmetic. The real answer requires two numbers per appliance and one rule about motors — and once you have them, every tier of the market becomes legible.
This page is that answer, built to be used: the master wattage chart for household loads, then each generator size class translated into realistic simultaneous combinations — not the fantasy version where everything runs at once, and not the stingy version that pretends you’ll monitor watts like a submarine engineer. Bookmark it; every sizing decision on this site routes through here.
The Two Numbers and the One Rule (60-Second Version)
- Running watts: what an appliance draws while operating.
- Starting watts: what motor-driven appliances (anything with a compressor or pump) demand for the first 1–2 seconds — typically 2–3x running.
- The rule: your generator must cover everything running PLUS the single largest surge that might start on top of it — and motors start when their thermostats decide, not when you do [→ /portable-generators/what-size-generator-runs-refrigerator/].
Add 20% headroom to whatever you calculate: generators shouldn’t live at their ceiling, for lifespan, noise, and the load you forgot [→ /portable-generators/how-loud-are-generators/].
The Master Wattage Chart
| Appliance | Running watts | Starting watts |
|---|---|---|
| Kitchen | ||
| Refrigerator/freezer | 200 – 700 | 1,200 – 2,200 |
| Chest freezer | 100 – 400 | 900 – 1,500 |
| Microwave | 1,000 – 1,500 | — |
| Coffee maker | 900 – 1,200 | — |
| Electric range (1 burner) | 1,500 – 2,500 | — |
| Toaster/kettle | 850 – 1,500 | — |
| Water & mechanical | ||
| Sump pump 1/3 HP | 800 | 1,500 – 2,500 |
| Sump pump 1/2 HP | 1,000 | 2,000 – 3,000 |
| Well pump 1/2 HP | 1,000 | 2,000 – 3,500 |
| Well pump 1 HP | 2,000 | 4,000 – 6,000 |
| Electric water heater | 4,500 | — |
| Climate | ||
| Gas furnace blower | 500 – 800 | 1,500 – 2,500 |
| Window AC (5–10k BTU) | 500 – 1,200 | 1,200 – 2,800 |
| Central AC 2-ton | 2,500 – 3,000 | 5,000 – 7,500* |
| Central AC 3-ton | 3,000 – 4,000 | 7,000 – 9,500* |
| Space heater | 1,500 | — |
| Box/ceiling fan | 50 – 200 | 100 – 350 |
| Living & work | ||
| Lights (LED, whole home) | 200 – 500 | — |
| TV + streaming + Wi-Fi | 150 – 400 | — |
| Laptop / phone charging | 50 – 150 | — |
| Desktop computer setup | 300 – 800 | — |
| Washing machine | 500 – 1,000 | 1,500 – 2,300 |
| Electric dryer | 5,000 – 6,000 | 6,000 – 7,000 |
| Garage door opener | 500 – 750 | 1,200 – 1,500 |
| CPAP | 30 – 60 | — |
| Oxygen concentrator | 300 – 600 | 600 – 1,200 |
| Power tools (circular saw) | 1,200 – 1,500 | 2,300 – 3,000 |
Halve the AC surge with a $300–$500 soft-start kit — the accessory that reshapes the entire upper market [→ /standby-generators/can-a-generator-power-central-air-conditioning/]. All figures are typical planning values; your appliance’s nameplate (amps × volts) is the source of truth.
Tier 1: 2,000 – 2,500 Watts — The Essentials Kit
The realistic combo: full-size fridge (its surge fits) + LED lights + Wi-Fi/modem + phone/laptop charging + a CPAP — with the microwave or coffee maker in turns, not in parallel.
What it can’t do: any two motor loads reliably (fridge + sump pump is a gamble), space heaters alongside anything, hardwired circuits (this tier is extension-cord territory [→ /portable-generators/connect-portable-generator-to-house/]).
The honest verdict: the apartment/condo tier and the medical-device tier — where its inverter refinement (48–57 dB, sip-fuel eco throttle) shines [→ /portable-generators/best-portable-generators-home-backup/]. Two units + a parallel kit later becomes ~4,400W if life changes [→ /portable-generators/parallel-generator-kits/].
Tier 2: 3,500 – 4,500 Watts — The First Real Home Generator
The realistic combo: fridge + chest freezer (staggered starts) + sump pump + LED lights + TV/Wi-Fi + microwave-in-bursts — the classic outage household, covered.
What it can’t do: electric water heating, dryers, central AC; and a 1 HP well pump alongside the rest is over budget — well homes, read Tier 3.
The honest verdict: America’s favorite first generator for good reason — the Champion/WEN dual-fuel class here costs $400–$700 and covers the actual mission of most short outages [→ /portable-generators/best-dual-fuel-generators/]. The inverter versions of this tier (iGen4500 class, ~52–61 dB) are the HOA answer [→ /portable-generators/quiet-inverter-generators-hoa/].
Tier 3: 5,500 – 7,500 Watts — Comfortable Outage Living
The realistic combo: everything in Tier 2 simultaneously and without staggering anxiety + gas furnace blower + a window AC or a 1/2 HP well pump + real kitchen use (microwave + coffee maker coexisting) + a washing machine cycle when needed.
What it can’t do: central AC (surge math says no without a soft-start and the top of this tier [→ /standby-generators/can-a-generator-power-central-air-conditioning/]), electric dryer + anything, whole-panel ambitions on the smaller units — check for 240V/L14-30 output before planning an interlock [→ /portable-generators/connect-portable-generator-to-house/].
The honest verdict: the value sweet spot of portable backup — Champion’s 7,500W dual-fuel class here delivers interlock-worthy multi-circuit living for $700–$1,000 [→ /portable-generators/best-dual-fuel-generators/]. Most households that “need a 9,500” after honest math actually live here.
Tier 4: 9,500 – 12,500 Watts — The Whole-Panel Portables
The realistic combo: the full essential home through an interlock — fridge + freezer + sump + well pump + furnace + lights + kitchen + laundry-in-turns — plus a small (2–3 ton) central AC with a soft-start kit installed, managed thoughtfully.
What it can’t do: be a standby generator. No automation (you start it, you flip the breakers), fuel logistics at scale (12–20 gal of gasoline per heavy day — the tri-fuel-on-natural-gas configuration exists precisely to solve this [→ /portable-generators/best-portable-generators-home-backup/]), and running everything at once remains a fantasy — you are the load management [→ /standby-generators/whole-house-vs-partial-home-backup/].
The honest verdict: the WGen9500DF/DuroMax XP13000 class is the ceiling of portable power and the floor of whole-home ambition. If your load calc genuinely exceeds this tier, you’ve left portable territory — the standby conversation begins [→ /standby-generators/what-size-generator-do-i-need/].
The Quick-Reference Verdict Table
| Watts | Realistic mission | Typical cost | The tier’s honest limit |
|---|---|---|---|
| 2,000 – 2,500 | Fridge + lights + Wi-Fi + CPAP | $400 – $1,300 | One motor load at a time |
| 3,500 – 4,500 | + freezer + sump + TV + microwave-in-turns | $400 – $1,100 | No electric heat/AC, no big pumps |
| 5,500 – 7,500 | + furnace fan + window AC or well pump + real kitchen | $700 – $1,000 | No central AC, no dryer stacking |
| 9,500 – 12,500 | Whole panel via interlock + small central AC (soft-start) | $900 – $1,800 | You are the automation; fuel is a job |
| Beyond | — | $9,000+ installed | That’s a standby generator [→ /standby-generators/whole-house-generator-buyers-guide/] |
Doing Your Own Math (The 10-Minute Method)
- List what genuinely runs simultaneously in your outage plan — the honest list, not the everything list.
- Sum the running watts from the chart (or nameplates: amps × volts).
- Add the single biggest surge gap among your motor loads (starting minus running of the largest).
- Add 20% headroom.
- Land on the tier — and before buying up a tier for one stubborn load, price the workarounds: a soft-start for the AC, staggered compressor starts, or simply putting the water heater on the “when the generator’s bored” schedule.
Worked examples of exactly this method live in the full sizing guide [→ /standby-generators/what-size-generator-do-i-need/], and the fuel side of each tier — how long those watts run per gallon or tank — has its own math [→ /fuel-running-costs/how-long-generator-run-5-gallons/].
Frequently Asked Questions
What will a 2,000-watt generator run? A full-size fridge, lights, Wi-Fi, phone/laptop charging, and a CPAP — with the microwave taking turns. It’s the essentials tier: excellent at its mission, gambling beyond it.
What will a 5,000-watt generator run? The comfortable middle: fridge + freezer + sump pump + furnace blower + lights + TV + microwave-in-bursts. Not: central AC, electric water heaters, or dryers.
What will a 7,500-watt generator run? Everything in the 5,000W answer simultaneously plus a window AC or a 1/2 HP well pump and genuine kitchen use — the tier where outage living stops feeling like rationing.
What will a 12,000-watt generator run? Essentially your whole panel through an interlock — including a small central AC with a soft-start kit — managed by you, one thoughtful breaker at a time. It’s the portable ceiling.
How many watts do I need to run a whole house? Honestly “whole house, no thinking” is standby territory: 18–26 kW installed [→ /standby-generators/what-size-generator-do-i-need/]. The portable version — most of the house, managed — lives at 9,500–12,500W.
Do starting watts really matter that much? They’re the whole game: a fridge that runs on 500W demands 2,000W for two seconds, and central AC triples the stakes. Every “my generator keeps tripping” story is a starting-watts story [→ /portable-generators/what-size-generator-runs-refrigerator/].
The Bottom Line
Four tiers, four honest missions: 2,000W keeps the essentials alive, 4,500W runs the classic outage household, 7,500W makes it comfortable, and 12,500W touches the whole panel — with a standby system waiting past the ceiling. Do the 10-minute math against the chart, buy the tier your list lands in (plus headroom, minus fantasy), and let the workaround accessories — soft-starts, staggered starts, load scheduling — bridge the stubborn last watts before a bigger engine does [→ /portable-generators/best-portable-generators-home-backup/].