[ljf]

Depends what you are warming - cold pasta dish? Just pop it in a pan with a little water or oil and will be hot in no time - can heat with gas (or wood, or biomass if you want to be truly off-grid [off-grid doesn't always meet environmentally friendly sadly...]). I guess that is one of the 'benefts' of off grid living in the UK - you will likely always have a fire burning anyway much of the year.

Heating with energy generated from solar is going to be 'costly' for some time. Amazed they run a tumble dryer - but guess it is very humid there?