We're renovating our house and looking at heating systems. It's 2,500 sq ft with 3 bathrooms and trying to choose between a combi boiler and a high efficiency condenser boiler. We had a combi boiler in our last home but it was small with only one bathroom - we found it great, having constant hot water and no need for a hot water cylinder. However I'm finding it hard to get a solid answer from plumber or plumbing merchants about whether it would suit our new home. Apparently you can also get a condensing combi boiler. Our first fix is coming up and also looking at radiator options - Does anyone have rads that are sized for a flow temperature of 50 degress so that the boiler will work in condensing mode and apparently save money? Does it mean that you need to go for larger rads? Finally, I assume it is better to overspec on radiator sizes because you can always turn them down as opposed to them not giving enough heat output... Any advice is welcome, Thanks