New boiler

[dumbo]

I have a Halstead 65F gas boiler. It's 24 years old but working. I am thinking of changing it for a new boiler, probably a Gloworm. The old boiler output is just over 19kw andheats the house ok. Gloworm make an 18kw boiler and a 24 kW boiler. My question is would an 18 kW boiler running more or less flat out be more or less efficient than a 24 kW boiler running at a more leisurely pace?

 

[jonnyswamp]

Pretty much all new boilers are modulating now, so as long as your heating and hot water needs don't exceed 18kw you'll be fine