AJH wrote:
I think I know the answer to this is to do nothing but...

The scene a 60s detached 3 bedroom house occupied by genteel, elderly,
active thinking but near housebound lady I have recently met,
previously heated by a redfyre back boiler, now broken with a melted
grate. I botched a repair with nickel arc rods but the internal
stresses caused it to break elsewhere and I haven't found a
replacement. I can try welding again (with a heat soak) or fabricate a
new one with a cast iron plate but it is 40 years old and I worry
about the flue. It purported to heat a room and 3 radiators by gravity
feed. The only good reason to retain it is that she has 2 tonnes of
anthracite in the bunker.

In the meanwhile she is using 5 convector heaters and one of these
with a 1kW radiant bar on. I've checked her meter reading and it is
1000 units over the electricity company's estimate for the quarter and
it's not even got cold yet!

At 80+ she will never see a return on the things I want to suggest,
like a small gas boiler (in the garage as she will not put up with any
noises) and replaced radiators, loft and cavity wall insulation.

I have no doubt the house would be totally renovated by any incomers
so any work will not add to the value and she is unlikely to move
willingly and the trauma is not justified.

Any suggestions on the most economic solution?

Powergen used to do an Age Concern endorsed fixed-rate energy package which
would cap her bills at a reasonable level. My parents are still on it, but
you'd have to check with uswitch or similar for availability.

If it's still available and suitable, then why not just switch her over, buy
her some more cheap leccy heaters, and reassure her that she can use them as
much as she wishes. Obviously there'll need to be an immersion heater as
well.