I bet they are only about 1 watt each so use bugger all power.
Slightly off topic, but this thread led me to find info about our cousins over the pond
We had a Caddy on hols last September, and were soooo impressed with the driver information center message, 'Heated Wash Wipes Pending, Heating Fluid'.
It's being discontinued though, probably because of this small recall....
2008 CADILLAC DTS
Manufactured between: 03/30/2007 and 11/30/2007
Defect: gm is recalling 857,735 my 2006-2008 buick lucerne; cadillac dts; hummer h2; my 2007-2008 cadillac escalade, escalade esv, escalade ext; chevrolet avalanche, silverado, suburban, tahoe; gmc acadia, sierra, yukon, yukon xl, saturn outlook; and my 2008 buick enclave vehicles equipped with a heated wiper washer fluid system. a short circuit on the printed circuit board for the washer fluid heater may overheat the control-circuit ground wire.
Consequence: this may cause other electrical features to malfunction, create an odor, or cause smoke increasing the risk of a fire.
Action: dealers will install a wire harness with an in-line fuse free of charge. the recall began on september 12, 2008. 