Electric heating systems for annexe

Northerner

Hi
We have recently moved house to enable us to have my father live in an annexe in the garden. The building is there but no heating at all, just a hot water tank and immersion for the shower room.
Dad is used to 24/7 heat, his bills are £250/mth currently!
The annexe is only a large living/kitchen/dining room (5.5m x 3.5m) the shower room (2m x 2m) and we are adding a bedrooms hitch will be approx 3m sq.
I don't have E7 tarrif currently as no need and ruby storage heaters would work as he requires heat from approx 0900-2200 daily as he has dementia and not very mobile.
Thanks for any advice as I'm only finding storage heating systems and not sure if the above is even available!

macman

You don't say what the heating system is in the main house? Does the annexe have separate metering? If so, E7 with NSH's is the obvious way to go.
If the metering is not separate and cannot practically be separated, then consider switching the main house to E7 anyway. It''ll probably cost you a bit more, but him a lot less-so overall a saving will be made.
However, given the major work you are doing on the annexe, I'd imagine that separate metering is the way to go.
No idea what you mean by 'ruby' storage heaters?

gazapc

I won't comment on the heating system choice but especially if you are heating constantly to a high temperature then insulate, insulate, insulate! Make sure the wall and roof insulation is as best it can be along with windows and floors (if possible).

Otherwise you will literally be burning money.