Fridge. Well pump. Furnace fan. That's the stack that decides whether you bought a generator or an expensive night-light.
Most 'what size generator' posts add every appliance in the house. Motors don't all start at once. Only the biggest surge counts on top of everything already running. Then add 20% so the machine isn't screaming at 100% load.
| Appliance | Running W | Starting W |
|---|---|---|
| Refrigerator (Energy Star, 20 cu ft) | 150 | 600 |
| Chest freezer (10–15 cu ft) | 200 | 600 |
| Well pump, 1/2 HP | 1,000 | 2,100 |
| Sump pump, 1/2 HP | 800 | 1,300 |
| Window AC, 10,000 BTU | 900 | 1,400 |
| Central AC, 2.5 ton | 3,500 | 5,000 |
| Furnace fan, 1/3 HP | 700 | 1,400 |
| Space heater | 1,500 | 1,500 |
| LED lights, whole home | 80 | 80 |
| Microwave | 1,000 | 1,000 |
| Electric water heater | 4,500 | 4,500 |
Same table as generator-sizer.com — manufacturer typicals, not invented. Fuel: gasoline ~1 gal per 7,000 W rated output per hour at 50% load; propane ~25% less runtime.
Essentials only (fridge + freezer + well + furnace fan + lights + phones) lands around 5,000–7,500 W. Add central AC or an electric water heater and you're in 10,000–12,000 W. A 30 A manual transfer switch handles 7,200 W; 50 A handles 12,000 W. Back-feeding a dryer outlet is how people kill linemen.