[thedoc (OP)]

I'm actually having a little bit of an argument with my husband at the moment regarding our electricity bill.  It’s almost doubled in the last year, and he seems to think that it’s because I leave the lights on constantly.  I disagree.  I think that it’s possibly the fact that he plays his Xbox maybe 24 hours a day over the weekend and he’s also got a hot tub out in the garden that’s heated constantly and a pond which has got a pump on it, and I would just like to know the actual difference between the cost of these various things.
Asked by Amanda Berta, Switzerland

               
               Read the naked scientists answer here
               
            

[thedoc (OP)]

Diana -    I'm actually a bit of a games consoler myself.  So, this was quite enlightening for me.  I've got some numbers for you.
I've made the assumption that you pay 15 pence per kilowatt-hour, assuming the Euro is on parity with the pound at the moment.  So let’s imagine that your husband is playing on a 42-inch LCD TV.  That’s pretty big and will draw about 200 watts.  So that will cost about 3 pence per hour and if you're doing two 5-hour sessions over weekends, that’s going to be about 30 pence per weekend.  Now his Xbox on its own draws about 160 watts, so that’s going to be 24 pence for the same amount of time.  The total will be about 54p for a 10-hour weekend session.
Now the hot tub is where it gets a bit serious, I'm afraid.  From my research, most hot tubs seem to use about 2,000 watts which is a lot and that’s going to cost about 30 pence per hour, so it’s going to be 90 pence for a 3-hour session, £2.40 for a full [8-hour] day and for a full week, £16.80.
Diana -    And then if you want to compare it with your bulb usage, so if you've got energy saving bulbs, I'm guessing that you're good boys and girls over there.
Amanda -    I don’t use them for all the lights, but we’ve got a lot of spots in our house.
Diana -    Well if you're using a nice 20-watt energy saving bulb and you've got three of them for 8 hours overnight, seven days a week, that’s going to cost you about 50p.  But if you've got the old fashioned incandescent ones, that’s going to be £2.52, but I'm afraid the whirlpool there or the hot tub, that’s going to be the real killer.

[Bored chemist]

Do you know how much energy gets used by air conditioning?