Heating accounts for about 53% of what you spend in a year on energy bills, so an efficient boiler makes a big difference. All well-maintained boilers burn their fuel very efficiently, but they inevitably lose some heat in the hot gases that escape up the flue (a pipe for extracting fumes and supplying fresh air to the boiler). Modern boilers are more efficient for several reasons, but their main advantage is that they are all condensing boilers. A condensing boiler has a larger heat exchanger, so it recovers more heat, sends cooler gases up the flue and is more efficient. Sometimes the flue gases get so cool that the water vapor in the gas condenses out, and even more energy is recovered from the condensing vapor. So you want to get the most heat out of your boiler relative to what it costs you per kilowatt hour, so it maybe worth considering a new boiler. BlueBurn can give you professional advice on this and other energy efficiency advice like thermostats , smart heating , radiator sizing , system water health and system flushing etc.
