How Many Watts Does a House Use?
Last updated:
Fact-checked by Marcus Hayes, Master Electrician (License #CA-EL-89241), 15 years generator installation experience.
Key Takeaways
- A typical US home uses 20,000 to 30,000 watts at peak demand and 1,000 to 3,000 watts at idle.
- For generator sizing, you only need to power essential loads — typically 5,000 to 10,000 watts — not full peak demand.
- Central AC is the biggest power draw: 3,500 running watts and 10,500 starting watts for a 3-ton unit.
- Essential loads (refrigerator, furnace, lights, well pump) total 3,000 to 6,000 running watts with a 3,000W surge.
- Use our appliance wattage chart for a complete list of 50+ household appliances with running and starting watts.
How many watts does a typical house use?
A typical US home uses 20,000 to 30,000 watts at peak demand (all appliances running simultaneously)
and 1,000 to 3,000 watts at idle (baseline loads like refrigerator, lights, and standby electronics).
For generator sizing, you only need to power essential loads — typically 5,000 to 10,000 watts — not
the full peak demand.
Wattage by appliance type
The most power-hungry household appliances are: central air conditioning (3,500W running, 10,500W
starting), electric water heater (4,500W running), well pump (1,000W running, 3,000W starting),
electric range (2,000W per burner), and refrigerator (800-1,200W running, 2,200W starting). Lights,
TVs, and phone chargers draw negligible power by comparison.
| Appliance | Running Watts | Starting Watts |
|---|---|---|
| Central AC (3-ton) | 3,500 | 10,500 |
| Electric water heater | 4,500 | 4,500 |
| Well pump (1/2 HP) | 1,000 | 3,000 |
| Refrigerator | 800–1,200 | 2,200 |
| Furnace blower (gas) | 600–1,500 | 1,500–3,000 |
| Electric range (per burner) | 2,000 | 2,000 |
| Sump pump (1/3 HP) | 800 | 2,400 |
| Lights (10 LED bulbs) | 100 | 100 |
| TV (LED, 55-inch) | 120 | 120 |
| Phone charger | 5–15 | 5–15 |
Frequently Asked Questions
How many watts does a house use?
A typical US home uses 20,000 to 30,000 watts at peak demand (all appliances running simultaneously) and 1,000 to 3,000 watts at idle (just baseline loads like refrigerator, lights, and standby electronics). For generator sizing, you only need to power essential loads — typically 5,000 to 10,000 watts — not the full peak demand.
How many watts does a 2000 sq ft house use?
A 2,000 sq ft house typically uses 25,000 to 35,000 watts at peak demand and 1,500 to 2,500 watts at idle. For essential backup (refrigerator, furnace, lights, outlets), you need 7,500 to 10,000 running watts. For whole-house including central AC, you need 18,000 to 22,000 watts.
What appliance uses the most watts in a house?
Central air conditioning uses the most watts: 3,500 running watts and 10,500 starting watts for a 3-ton unit. Electric water heaters use 4,500 watts. Electric ranges use 2,000 watts per burner. Well pumps use 1,000 running watts and 3,000 starting watts. The refrigerator uses 800 to 1,200 running watts with 2,200 starting watts.
How many watts do I need to run my whole house?
To run a whole house including central AC, you need 20,000 to 26,000 watts — typically a 22kW standby generator. To run essential loads only (refrigerator, furnace, lights, outlets, well pump), you need 7,500 to 10,000 running watts. Use our generator size calculator for a precise figure based on your appliances.
How many watts does a refrigerator use?
A refrigerator uses 800 to 1,200 running watts and needs 2,200 starting watts for 2 to 3 seconds when the compressor starts. It is one of the most important appliances to keep running during an outage because food spoils after 4 hours without power.
How many watts does a well pump use?
A typical submersible well pump uses 1,000 running watts and 3,000 starting watts for a 1/2 HP pump. A 1 HP pump uses 2,000 running watts and 6,000 starting watts. Well pumps have high starting watt requirements because of the pressure switch and water column weight.