Watts consumed by refrigerator
How much electricity does a 700 watt fridge use?
A refrigerator has a 700 watt compressor that runs only 20% of the time. Assuming a cost of $0.11/kwh for electricity, what are the watts consumed by refrigerator and how much does it cost to run this refrigerator for a month?
Assuming there is another, more energy efficient refrigerator, which has a 550 watt compressor, and that refrigerator costs $200 more, how many months will it take for the extra $200 investment to pay for itself?
Answer - Best Answer on Yahoo! Answers
You shouldn't look at the wattage of the compressor to determine how much electricity the refrigerator will use, any more than you would look at the horsepower of a car to figure out its mileage. "Watts consumed by refrigerator" is only a measure of the power use when the compressor is running. But two refrigerators could use the same watts when the compressor is on, but be vastly different in energy use (for example, if one has no insulation and the other is very well insulated).
A brand new fridge
Photo by daysies, via FLICKR
You need to look at the energy efficiency rating of the refrigerator in terms of its rated kwh per year consumption. Divide that by 12 and multiply by 0.11 and you'll get your monthly costs. Compare the monthly costs of your two fridge choices to get the difference, and divide the $200 extra by that (assuming the more expensive fridge is also the more efficient one) and you should get the numer of months it will take to recover the additional cost.
For example, consider these two refrigerators:
- Whirlpool, 18.2 cubic feet, top freezer, 484 kwh/year=$4.44/month
- Frigidaire, 18.2 cubic feet, top freezer, 376 kwh/year=$3.45/month
Savings is $0.99 a month, which means it would take 202 months or 16.84 years for the extra $200 investment to pay back in energy savings - probably longer than you'll keep the fridge.
Of course, don't forget that energy costs are not constant - they will probably rise over time so the investment will probably pay back sooner.
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If one of these fridges is what you already own, buy a Kill A Watt meter or other electricity monitor and measure its use over a three day period to get its daily kwh rating, then multiply by 30 to get its monthly consumption.
The best website for finding refrigerator efficiencies that I've found is from the Canadian government, since it lists both ENERGY STAR rated fridges (ones that are at least 20% more efficient than the standard) and ones that aren't efficient enough to get ENERGY STAR certification. That way you can check whether a fridge a salesman is selling you is actually efficient or not. It's at the second link below; the first is a page on making effective use of your current fridge and how to buy a new one.
Green Energy Efficient Homes and other articles cited
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