Social Housing Landlord

Chrysalis

This sounds like a window issue, unless the boiler (or rest of heating system) isnt working properly, then it wont make your home warmer, it would just cost less to run.

Albermarle

I have lived in my home for 15 years, and according to the Social Housing Landlord's website, boiler replacement should be every 15 years. Every website I've looked at also suggests 10 - 15 years.

Not sure what websites you looked at, maybe ones who have a vested interest in replacing boilers?
The advice on these forums is not replace a working boiler, however old it is ( that is if you are paying for it yourself) .
However if they have a major breakdown and they are more than 15 years old, that could be the time to look at replacing it.
They should for sure last more than 10 years. Some new boilers have a warranty >10 years.
A newer boiler would probably use a bit less gas, but would not necessarily heat your home up any better, unless there is really something wrong with the current one.

pinkshoes

rarasarr23 said:

Update: EPC was done in January and now showing on relevant website. Discussed boiler performance with energy team, and they are sending someone out to check if it's working efficiently. If they say it's ok, then I'll focus on trying to get them to offer some extra insulation for the window frames.

That's great they're checking the boiler, but a 15 year old boiler that has been maintained will work really well and still be relatively efficient. A new boiler won't make that much difference. So it is far more sense to maintain the old boiler until parts cannot be obtained.

Our previous boiler lasted over 40 years and was fine.

This sounds far more like an issue with the windows.