[clivem2]

Today I found that the mirror heating comes on at a higher temp than the 3C ice warning. At 5.5C the mirrors were gently steaming (HRW off). I suppose there's a narrow temp band when there's condensation with the heating off so it should be a rare occurrence...my only other slight grumble is that the heating is not very powerful so it takes a while to clear condensation. Presumably as the heating is on all the time under a preset temp, the heating needs to be gentle to save power. I'd prefer high power heating on a separate switch with a timer set for a short time period.