boiler size?

[neverwantedthis22]

I urgently need to buy a new boiler. Two different companies have suggested the Vaillant ecoTEC plus 832 Combi Gas Boiler.

We have a 5 bed/2 bathroom house (loft conversion Victorian semi). The one it's replacing is a 30kw but that was for a 3 bed house before we extended into the loft. Would a 32kw boiler be OK or would it be advisable to go larger? 35kw or 38kw or given there's only ever one shower at a time (it's just me and 2 kids now) a 32kw will be fine. I'm thinking longer term for when I'm forced need to sell the house.

It's a tough one because on the one hand you don't want one bigger than you really need, it will be less efficient.

OTOH it is miserable having one that is too small and not being able to have everything you want at once, two showers etc.

I suppose the question is, was the last one adequate for running the two showers simultaneously.

Two more points. One is does it really cost that much more for the more powerful one in the grand scheme of things - ie install costs. The second thing is I would be surprised if any potential buyer checked out a) what the boiler power was and b) whether it was sufficient before buying the house. People these days do have a tendency to ask for inspection of the boiler/boiler service before buying, but I don't think that typically assesses whether it is sized correctly.

Thank you GasPanic. The man that came to try and fix my boiler said today that even the larger size combi boiler won't allow you to have two showers at once - which was a surprise to me as I'd assumed the larger size one would let us do that. It's about £140 difference so I guess it's better to go with the bigger one.

AIUI the required size of combi boiler is usually governed by the domestic hot water required and not the size of the house or number of radiators to heat.

If you want to run two hot taps at once and have a reasonably powerful shower, then any boiler that can do that will almost certainly be capable of heating the house just fine.