Heating & cooling: how many watts they use
Space heaters, air conditioners, heat pumps, furnaces, fans and water heaters. The biggest draw here is the electric water heater at about 4,500 W; the smallest is the humidifier at about 40 W.
| Box fan120 V | 7540–110 | — | 0.6 |
|---|---|---|---|
| Ceiling fan120 V | 505–100 | — | 0.4 |
| Central air conditioner240 V | 3,5002,000–6,000 | 7,000 | 29.4 |
| Dehumidifier120 V | 400235–700 | 800 | 3.8 |
| Electric blanket120 V | 10050–150 | — | 0.4 |
| Electric fireplace120 V | 1,500300–2,500 | — | 3 |
| Electric water heater240 V | 4,5003,500–5,500 | — | 13.5 |
| Furnace blower120 V | 500150–1,000 | 1,400 | 4.2 |
| Heat pump240 V | 3,5002,000–6,000 | 7,000 | 33.6 |
| Humidifier120 V | 4020–300 | — | 0.4 |
| Mini-split240 V | 920300–2,500 | 1,000 | 5.5 |
| Portable air conditioner120 V | 1,125800–1,400 | 1,800 | 5.4 |
| Space heater120 V | 1,500750–1,500 | — | 6 |
| Window air conditioner120 V | 660440–1,200 | 1,500 | 3.2 |
Guides on this topic
What size generator do I need? A simple sizing method
Add running watts, then the largest starting load. Worked examples for outage essentials, a well pump and whole-house central AC, plus a size chart.
Running watts vs starting watts: what the difference means
Running watts keep an appliance going; starting watts get motors moving. Which appliances surge, why you add only the largest, and rated vs peak.
Generator transfer switch vs interlock kit: what each does
What a generator transfer switch and interlock kit do, what the NEC requires, inlet boxes, manual vs automatic, and why backfeeding an outlet is dangerous.