How much does a common house use of energy in a year?

Question

if you can explain this simple

Answer 1

Short answer is about 18,000 Kwatts per year on average.

Here is more:

More information is needed to address this question well. What type of appliances are being run? Is it an all electric house? What appliances run on gas? Is there a Central Heat and AC? What is the approximate square footage? With answers to these questions you can get a pretty good ball park answer.

Otherwise I will contribute this: As an electrical engineer for a power company I see on average a house that is 1600-2000 square feet and having electric appliances except for the furnace use an average of 1500Kwatts per month making 50 Kwatts per day and a total of 18,000 Kwatts per year.

Having said that it is also important to know why the question is being asked. If, for example, one is trying to determine usage as part of a plan for creating an alternative energy system for the house, one really needs to find out the actual usage for the house. Average numbers can be very misleading. Nova ran a story about a couple that installed a solar based 6 kWatt system who were generally running a surplus. No data is provided for actual consumption and converting the rating of a solar system back to Kwatts/day is moderately complex. On the other side of the spectrum, it has been reported that Al Gore's mansion uses about 221,000kWh per year. If you scale this number down to the requested 1600-2000 square foot house, the result is around 60,000 Kwatts per year. It is reasonable to assume that Mr. Gore has already done all of the obvious things to reduce his energy footprint (e.g. energy star appliances, energy efficient lighting) so this clearly should not be considered an upper bound on electrical usage.

The most important part about this question is that knowing the average value is useful if you just want to know the average but knowing the specific number may be significantly more important in some cases.