Warmth that suits the house.

Usually, yes. Most sealed systems have a filling loop or a built-in filling key under the boiler, and the manual shows how to use it. If you are topping up more than once every few months, there is a leak or a failing part, and that needs an engineer.

Often. If the heat exchanger is sound and parts are still made, a repair is usually the better value. If the heat exchanger is leaking, parts are obsolete or it breaks down every winter, we will tell you plainly that replacement makes more sense.

Combis suit flats and smaller homes with one bathroom and good mains pressure. Homes with two or more bathrooms usually do better with a system boiler and a cylinder. Older houses with tanks in the loft sometimes keep a regular boiler to avoid stressing old pipework. We recommend after the survey, not before.

A like-for-like swap is often done in a day. Converting a regular system to a combi, moving the boiler or taking tanks out of the loft takes longer. The quote gives you a realistic timeline.

Usually around an hour for a domestic boiler, longer if it needs a deeper clean or a part replaced.

A correctly designed system is sized for the coldest weather your area typically sees. It feels different, steady warmth rather than hot radiators, but the rooms should hold the temperature you set.