The Regulations also call for zone control of the bedroom area -for existing systems this is usually most easily achieved by the addition of thermostatic radiator valves to the bedroom radiators. 

From Spring 2005 (for gas) and 2007 (for oil) the Building Regulations will require that (except in certain special cases) all new and replacement boilers, are of the high efficiency type -sometimes termed condensing boilers. 

A condensing boiler is a more efficient appliance which cools the flue gases to the extent that the water vapour produced during combustion is condensed within the boiler (hence recovering the latent heat of evaporation) and must be run to drain. 

Note that some water vapour remains in the flue gases, and condenses when it comes into contact with the colder outside air, and so this type of boiler produces a "plume" -a "cloud of steam" - from the flue terminal whilst in operation. Careful positioning of the boiler and flue is necessary to ensure that this is not a nuisance.