Combi Boiler swap

Altior

Thanks, Boxt provide a 10 year warranty with this model. Along with the usual caveats, and requirement to maintain the annual service schedule (which is a given, anyway).

WIAWSNB

It's a repeated debate point, but the simple scientific fact is, the higher you have the inside temp, and for longer, the more it'll cost.

But, each person needs to balance potential savings against their personal requirements, so if that is 'warm', then warm it needs to be.

Your new boiler will undoubtedly be more efficient in any case, and - yes - a lot quieter.

Your old boiler was likely more noisy from birth, but the main noise-generating part, the burner fan, is very likely to also have wear which will greatly add to this. I think you'll be happy with the 4000.

Albermarle

It's a repeated debate point, but the simple scientific fact is, the higher you have the inside temp, and for longer, the more it'll cost.

I agree, but the OP has only a one bed flat. If it is reasonably well insulated/surrounded by other flats, then heat loss will should not be that high.

If it was a draughty older bigger house then keeping it at above 20 degrees 24/7 , would be very expensive.