Nice idea Susan but these Eberneezerspatula units are a bit pricey Tris
Ive got the silver bubble bk insulation sheets and wrapped my 500 litre tank.Last winter and currently i use the oil radiator, its only dinky and a digi timer plug. I set it for an hr at midnight till 1am then bk on at 3-4 and finally at 5-7 or sometimes longer. I have a 2006 fiat scudo and inside of roof is lined with same insulation. Not had any problems with freezing.Currently waiting on hearing how someone has got on with a hot tub heating pump. Look on the thread "is anybody using this to heat the water" thread.
where does one purchase the silver bubble stuff.?