Can anyone tell me how much power heated mirror pads use? Ideally in laymans terms - i.e. pounds, shilling and pence. So, for example, if one of these is hooked up to the lighting circuit and someone takes a 20 mins shower, what would the cost be to use?

OK. I have a bathroom cabinet measuring 600 x 300 so thinking about something like the following that I have found - item 828.90.913. http://www.locksonline.com/acatalog/demista-heated-mirror-pad-2727.html It states 25W on the information sheet further down the page - how do i work out what this is going to cost me for a 20 mins shower?

Hi just checked out the info. The demister pad becomes effective after 2/4 minutes. It is 25W. 25W over a 20 min period is 20/60h x 0.025kW=0.0083kWh If you look up the rate you pay per kWh and multiply it by 0.0083 that will tell you how much it costs. ie If ,say, your rate is 20p per kWh then 20 x 0.0083 = 0.17p.

Thank you very much. I'm OK at DIY, but not great working out all the electrical bit! Thanks for explaining - looks like the other half will insist on the pad

As UP calculates. I would do it slightly differently, although only to make it clearer in my mind. You pay 20p (say) per unit of electricity. A unit of electricity is 1 kilowatt for 1 hour, (or half a kilowatt for 2 hours, or 2 kilowatt for half an hour). This unit is known as a KWh (Kilowatt Hour). To work out the cost, multiple the KW of the appliance (the wattage devided by 1000) and multiply this by the number of hours and the pence per unit. 25watt / 1000 = 0.025KW 0.25KW * 1hour * 20pence = 0.5pence (thats 25watts running for a whole hour) 0.5pence / 60minutes = 0.008333333333333333333pence per minute 0.008333333333333333pence * 20minutes = 0.166666666666667pence. So, 0.17p per 20 minutes. Same result, swings and roundabouts