On Wed, 30 Sep 2020 16:38:13 +0100, Mike Clarke wrote:

Don't install one that is overated - our house has 16 rads/hot
water
cylinder but a 24kw boiler is OK.

Unless it supplies a shower and it's a combi boiler and you want a good
flow of hot water.

24 kW will give you 10 l/min with a 35 C temprise (15 to 50 C).

Yer average electic shower can only manage about 4 l/min with the
same temp rise.

I guess it depends on what you call a "good flow of hot water". Best
shower I've ever had was a small waterfall down onto a beach in
Jamaica. That was probably closer to 60 l/min, wasn't hot though but
very pleasant all the same.

--
Cheers
Dave.