Guy's a positive energy source

DO YOU know how to calculate the energy efficiency of your home?

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It’s easy. You take your latest energy bills, round them up to the nearest pound, multiply this by how many rooms you have, add your property's height, subtract its width, divide this by the number of windows, multiply that by the number of weeks Paul McCartney and Wings stayed at No.1 with Mull Of Kintyre, then jot down the figure you’re left with. Then wait 10 seconds, cross that out, and write: “My home is not remotely energy efficient. Frankly, it’s a joke.’ Because that, I’m afraid, will almost certainly be the right answer.