Got a back boiler behind the gas fire in the living room. It’s been there since the house was built in the 70s and somehow still going, but the hot water takes forever and the radiators upstairs are barely warm even when it’s been on for hours. Had a gas safe engineer out in the spring who said it was safe for now but “getting tired” which is a phrase I could apply to myself 
Not sure whether to bite the bullet and get a combi boiler fitted before winter properly arrives, or nurse it through one more year. I have no idea what a reasonable quote looks like these days. Is 3k realistic or am I dreaming? The fire would need to come out too obviously, so that’s more disruption.
Also wondering if there are any grants or schemes for pensioners, I vaguely remember something about ECO funding but can’t work out if I’d qualify.
We had a back boiler taken out of our 1950s place about six years ago and replaced with a combi boiler in the kitchen. The difference in hot water speed and heating response was night and day, genuinely transformative.
Cost at the time was around £2,800 including removal of the old unit and making good the fireplace opening. I would expect it to be closer to £3,500 now. One thing to be very careful about is asbestos. Our old fire surround turned out to have asbestos rope seals and some of the flue liner was asbestos cement, which added about £400 for specialist removal. Worth getting a Gas Safe engineer to have a look first and flag whether there is any asbestos present before you commit to anything.
The other benefit is that a modern combi will be significantly more efficient. Our gas bills dropped noticeably after the switch. If you are thinking about staying in the house longer term it probably pays for itself within five or six years.
@Ferngate52 That’s really useful, thank you. The asbestos bit has slightly terrified me though Had no idea that could be lurking in there. Would a Gas Safe engineer normally flag that when they come to look, or do I need to get a separate asbestos survey done first? Don’t fancy paying for two visits if one person can do both.