Mitsubishi Electric's domestic range of Ecodan air source heat pumps has again received the official backing of the Noise Abatement Society (NAS) in the annual awarding of its official "Quiet Mark" of approval. <br> <br> The renewable heating product is currently the only air source heat pump on the Quiet Mark listing and will be exhibited as part of the NAS's special "Quiet House" at the Ideal Home Exhibition (March 15 – April 1 at London's Earls Court).<br> <br> Air source heat pumps are now covered by Permitted Development under new guidance which came into effect at the end of 2011. However, in order for the installation to be allowed under these planning regulations, it must comply with the MCS020 Planning Standard and this includes strict guidelines on noise levels.<br> <br> Ecodan is suitable for a wide range of existing and new built properties and harvests renewable energy from the outdoor air – even in sub-zero temperatures – to reliably provide a home's heating and hot water all year round, Mitsubishi explains.<br> <br> www.domesticheating.mitsubishielectric.co.uk