On Nov 21, 6:37*pm, wrote:
That's one thing we do have - *lots* of space.

If you have the space and a wet system, you can always top-up that
thermal store from multiple sources - wood burner boiler, chimney back
boiler, electric air source heat pump, vacuum solar array, economy 7.

Wet electric central heating systems tend to have a limited water
storage capacity because they are aimed at well insulated small flats.
They use Economy 10 to top-up the thermal store & then costly on-peak
when necessary, but few suppliers offer Economy 10 so it is costly
with little price competition. Some loony builders have been known to
skip on even Economy 7 and wire to peak rate.

Since you have the space a very large thermal store with Economy 7
could be used, but the key question is how much do you need - poor
insulation could require a silo of hot water cylinders and run out of
electricity supply capacity. It then becomes a case of design for -5oC
on Economy 7 and use peak-rate top-up for the periods when colder.
House insulation is key to any electric heating, do it sufficiently
and panel heaters on peak rate can do it.