Watt & Kilowatt
The unit of electrical power: volts multiplied by amps. A kilowatt (kW) is 1,000 watts, the scale used for generators, EV chargers and heating equipment.
Watts are what electricity actually does: a 100-watt bulb, a 1,500-watt space heater, a 5,000-watt (5 kW) AC condenser. The math is simple and useful: watts = volts × amps. A 1,500-watt heater on a 120-volt circuit draws 12.5 amps, which is why two heaters on one 15-amp circuit trip the breaker every time.
Kilowatts size the big equipment. Standby generators are sold by kW output (a 22 kW unit covers most whole homes), EV chargers deliver 7 – 11 kW, and electric furnaces draw 10 – 20 kW. When you compare equipment, kW tells you both what it can power and what your electrical system must be able to feed it.
Talking to a contractor about this?
Run the project past a licensed electrical pro first. Calls are answered around the clock and routed to a pro serving your area.
- Volt : The unit of electrical pressure pushing current through a circuit.
- 120V vs 240V : US homes receive two 120-volt legs from the utility.
- Voltage Drop : The loss of voltage along a wire run, caused by the resistance of the wire itself.