Replacing a gas boiler can be an expensive game. With energy prices being volatile too is it worth looking into alternative heating.
Heat Pump. A very efficient heating option, producing 3 or 4 times more heat than a conventional electric heater.
Infrared heating panels. A highly effective method of heating. It operates silently, Takes up little space and has little maintenance.
Solar Thermal Panels. Although sadly not enough to meet a typical house’s heating needs on its own, they are often fitted with either of the above. A home heating system that uses heat from the sun. Although upfront costs can be high.
Biomass Boilers and Stoves. The system can burn logs or wood chips and pellets. A stove would be used to heat just one room where A boiler is an alternative to a gas boiler and can heat your whole house. The downside of this one is that it will need regular cleaning.