The CE mark, or formerly EC mark, is a mandatory conformity marking for certain products sold within the European Economic Area (EEA) since 1985. The CE marking is also found on products sold outside the EEA that are manufactured in, or designed to be sold in, the EEA.
Condensing boilers are water heaters fueled by gas or oil. They achieve high efficiency (typically greater than 90% on the higher heating value) by condensing water vapour in the exhaust gases and so recovering its latent heat of vaporisation, which would otherwise have been wasted.
Gas Central Heating. Learn more about gas central heating systems and gas boilers, including the average costs per year - so you can find out if you're paying too much. Most households in the UK have mains gas central heating. Find out if you're paying too much for gas and learn more about the pros and cons of gas central heating. Gas central heating is a so-called âwet systemâ, which means a gas-fired boiler heats water to provide central heating through radiators and hot water through the taps in your home.