About 80% of UK households have a gas-fired boiler and gas-fired central heating system. Condensing gas boilers became mandatory in 2005 and were pitched to installers and consumers as a huge technological leap forward that would save up to £350 on our gas bills. We were all encouraged to upgrade from a G-rated non-condensing boiler to an A-rated condensing boiler.
The problem was that newly-installed A rated condensing gas boilers were not being set by the installers to run at their A-rated efficiency. A study carried out by the Energy Saving Trust more than a decade ago found that 99% of households were actually running their A rated gas boilers at B, C, D or even E rated levels. Boilers in the home were significantly underperforming compared to what was touted on the labels.
Then in 2020, it was discovered that these boilers were estimated to produce 14 percent of the country's harmful greenhouse gas emissions so then the Government proposed to phase out all gas boilers by 2035 in our bid to be carbon neutral by 2050.
It was suggested they could be replaced with a “hydrogen-ready” boiler that would initially burn natural gas and switch to hydrogen when it became available. Hydrogen boilers are still not yet available. (see our blog on Hydrogen-ready boilers)
Another report by the Heating and Hot Water Council (HHIC) last year found that nearly all combi boilers are still not optimised to run at the advertised A rating but in fact only equivalent to just 75-85% efficiency
The key is the 'flow temperature' This is the temperature your boiler heats up the water to before sending it off to your radiators. Most gas boilers are set up to operate at what is called 80/60 flow and return temperatures. This means the boiler heats up the water (called ‘the flow’) to 80°C. The water returns to the boiler after travelling around all your radiators (called ‘the return’) at 60°C, having given off 20°C to the room.
The usual 80/60 flow and return temperatures are too high for a condensing gas boiler to achieve the A-rated efficiencies shown 'on-the-box'.
The correct temperature setting for heating on a combi boiler is 'as low as possible', but as a guide most older homes can run their heating systems at 60-65°C and newer homes at 50-55°C. They start to reach their very highest efficiency potential at 45°C flow temperature or lower, but this can be too low to heat older properties to a comfortable level.
Many households are accustomed to short heat up times because they run so hot. Lower flow temperatures will mean slightly longer heat up times. So set correctly, households would be able to save around 6-8% in gas just by turning down the heating flow temperature on their condensing combi boiler. Reducing the operating temperature for heating will help your boiler run more efficiently without reducing your comfort.
For those who have the heating on much of the day, you will move to lower temperatures for longer periods which will have a huge positive impact on fuel bills.
Additional energy savings can be made by getting a programmable thermostat, getting the boiler serviced at least every year, insulating your home throughout including the loft, windows and doors, not covering radiators and not leaving windows or doors open for a long time.
Use SMART technological innovations to reduce heat loss, monitor your energy consumption in real time, with greater accuracy. You can also remotely set your systems and appliances to run at the best times on the lowest price tariffs, using your mobile phone.
SMART thermostatic radiator valves could save up to £75 and 330 of carbon a year, for example.