Just been out to buy 2 15 tog (?) Quilts, a paraffin heater, and a frost jacket and blanket for my chems. Bloody TM will be more snug than me through the winter!
So what you really do is buy 2 x 15 tog quilts for the equipment in the van, but these new ones go straight into the house whilst the older ones (from the house) go into the van. A nice way of spending business cash on the household things!
As for chemicals, those that can sustain the cold whilst in the garage (again wrapped in quilts) stay there, whilst those like P-Gold come into the house.
Reduce the air space in the van with quilts and electric heater pointed at machine.
But like you say, I've opened the van doors in Feb to find it warmer in there than it is in the house.....something not right there