How Much Does It Cost to Run a Microwave?
A microwave costs about $0.01-0.03 per typical use (2-5 minutes). At 1,000 watts, running for 5 minutes costs about $0.013. Monthly cost for average use is $1-3, making microwaves very energy efficient.
Key Takeaways
- Microwaves use 600-1,200 watts while running.
- Convection microwaves use more power when the convection feature is active.
- Using the microwave instead of the oven for small items saves significant energy.
Explanation
Microwaves use 600-1,200 watts while running. A 1,000W microwave running for 3 minutes uses 0.05 kWh, costing less than a penny at $0.16/kWh.
Microwaves are highly efficient because they heat food directly rather than heating air or cookware first. Reheating in a microwave uses 80% less energy than reheating in a conventional oven.
Standby power is minimal—about 2-5 watts for the clock and controls. This adds about $3-8 annually, which is the main 'cost' when the microwave isn't actively cooking.
Microwave wattage ratings refer to cooking power, not total electrical draw. A microwave rated at 1,000 cooking watts actually draws about 1,400-1,700 watts from the outlet because magnetrons are roughly 60-65% efficient. The remaining energy is lost as heat through the magnetron and transformer, which is why the microwave itself gets warm during use.
Defrosting in the microwave uses the same wattage but cycles on and off at reduced intervals. A typical 10-minute defrost cycle uses about 0.15 kWh, costing around $0.02. This is far more energy-efficient than defrosting on the counter (which risks food safety) or running warm water, which wastes both water and the energy used to heat it.
Compact microwaves (600-800 watts) take longer to cook but draw less power per minute. For quick reheating tasks under three minutes, there is little cost difference between a 700W and a 1,200W model. However, for longer cooking sessions like steaming vegetables (8-10 minutes), the higher-wattage model finishes faster and uses roughly the same total energy.
Microwaves are especially cost-effective for boiling water in small quantities. Heating one cup of water takes about 90 seconds in a 1,000W microwave, using 0.025 kWh. An electric kettle heats the same cup in about 60 seconds using 0.03 kWh, while a stovetop burner takes 3-4 minutes and uses 0.10-0.15 kWh due to heat escaping around the pot.
Things to Know
- Convection microwaves use more power when the convection feature is active.
- Using the microwave instead of the oven for small items saves significant energy.
- Over-the-range microwaves have exhaust fans that add minimal power draw.