Winter heating, whats the most efficient way to set it up?

[Werewolf]

the water tank with thick solid insulation is probably a hot water tank, either fed heated water from the boiler or uses an electric heater to heat water.

The white thing you describe for the hot water sounds like a small water heater for a single tap/outlet.

Do you have a (usually) fairly large white metal thing? (probably close to 50cm by 80cm by about 30cm) hidden somewhere?

 

[Marcos]

(probably close to 50cm by 80cm by about 30cm) hidden somewhere?

yeah thats about the size of it, its not one of the small single tap ones, i use to have one of those at another place and this one is much bigger

they are side by side in the airing cupboard, but i dont really get why there is two of them, i always thought a house had one or the other.

like at home i dont have the water tank, i just have the large white box that comes on every now and again and blasts some hot water around the system