thermal store for hot water.

[addjunkie]

Does she have solar pv, if so you can get a gadjet, think its called eco boost, that basically switches immersion on when ever there is spare juice from the solar panels, for example when wvery body is at work during the day.

There is also a thing called thermaboil like a small heat pump for hot water in the form of a solar panel, not recomending the company but the technology may be worth looking in to

http://www.homerenewables.co.uk/thermodynamic-panels/?gclid=CJSmrZiKiMgCFUEaGwod52ELyQ


If looking into wood stoves with back boilers some will replace a boiler and do the whole house, but an option if logs easily available

 

[striker]

No solar pv. Thermodynamic panels look interesting.
Fortunately she has a great supply of logs from a friends log company..probably for a small donation.

 

[Kent]

1 kw should be 80 litres min off memory for heating purposes
Within reason the bigger the better