I use my microwave only for reheating food,at 75-80% power (450w-600w),and only for 10-12 minutes everyday. Is it going to case high electricity bill? Any idea what will be the extra unit?

NO.

I’ll go through the numbers. 600 watts x 0.8 = 480 watts

12 minutes is 1/5 hour

480 watts x 1/5 hour = 96 watt-hours

96 watt-hours per day x 30 days/month = 2880 watt-hours/month or 2.9 kW-h per month

Typical price is 10 cents per kW-h

2.9 kW-h per month x 10 cents per kW-h = 29 cents per month

pretty cheap, 29 cents per month

If we were sharing the electricity bill, I would ask you to pay for 5 units (that is 5 kWh) each month.

References :NO.

I’ll go through the numbers. 600 watts x 0.8 = 480 watts

12 minutes is 1/5 hour

480 watts x 1/5 hour = 96 watt-hours

96 watt-hours per day x 30 days/month = 2880 watt-hours/month or 2.9 kW-h per month

Typical price is 10 cents per kW-h

2.9 kW-h per month x 10 cents per kW-h = 29 cents per month

pretty cheap, 29 cents per month

References :The point of using a microwave is to reduce your total power consumption.

So, per day, (assuming the higher figures you give) you use 600 * 0.2 watt-hours per day = 120 watt-hours = 0.12 kilowatt-hours.

What you need to compare this with is the cost or other ways of re-heating the food. A stove, for example, might use 1200 watts for 30 minutes per day ==> 600-watt-hours = more than 4 times what you need with the microwave. So, you are ‘saving’ 480 watt-hours per day, which means you are reducing the daily power consumption.

References :Household Appliances

The golden rule is, "If you are not using it, turn it off!" About 30 percent of the average consumerâ€™s electric bill results from use of these appliances:

Appliance KWH Per Month Cost Per Month

Pool pump 259 $20.72

Refrigerator-freezer 134 $10.72

Waterbed 100 $8.00

Clothes dryer 56 $4.48

Range oven and surface 54 $4.32

Television or stereo 46 $3.68

Lighting 40 $3.20

Electric blanket 20 $1.60

Dishwasher 19 $1.52

Automatic coffee pot 10 $0.80

Microwave oven 10 $0.80

Clothes washer 5 $0.40

Iron 4 $0.32

Radio 4 $0.32

Hair dryer 3 $0.24

Toaster 3 $0.24

Vacuum cleaner 3 $0.24

Clocks 1 $0.08

*Residential Electric Profile-based on an electric rate of 8 kilowatt per hour (2-3 people per household).

References :http://www.psc.state.fl.us/publications/consumer/brochure/ConserveYourWorld/cyw3.aspx

power is measured in watt-hours. In your case this would be 1/5 x 1 watt-hour… I dont know what the charges are for a watt-hour in your area.

References :electricity

Using the microwave uses less electricity than a heat producing appliance such as an electric range or a smaller heating appliance such as waffle iron or coffee pot.

References :