What boiler is the correct one for my home

Hi reh11 It's a little difficult to be precise without a site visit but your option would be: A system boiler in excess of 18kw, this would negate the need of the small feed and expansion tank in the loft. The current pipework would need to be pressure tested to ensure it can perform at the higher pressure a sealed system needs to operate at. The hot water cylinder, which is currently vented and fed by the big cold storage tank in the loft, could be replaced by an unvented cylinder. This is fed by mains cold water and will give hot water at mains pressure. This is only possible if your current mains water supply is up to the task. If not there is the option of a cold water accumulator but this would probably not be an option if you're looking to save space. Because all new boilers are now of the condensing type they operate at a lower temperature. Depending on the level of insulation you have in the house it is sometimes necessary to increase the size of the radiators to achieve the heat output required. Regards Roy