I am just agreeing a new boiler to be fitted (so hardly DIY at all, I'm afraid).
It's for a 2 bedroom flat and it needs to heat the flat and fill the bath at a reasonable rate. At some stage, I may fit a shower, so the boiler needs to cater for that too (although not both at the same time).
Is a 28 KW boiler about right for that job? Or is it overkill?