We have just finished installing a new oil fired combi heating system for a customer whilst they are away on holiday. Very grateful to have a good customer who trusts us to work in their house while they are away, it’s easier for us and much easier for them as they don’t have to deal with the inconvenience. We removed their old system a lot of which had been installed by a DIYer and was pretty much sub-standard and with an old boiler with 30 year old technology. A new system with good design and installation, modern efficient radiators and a great new Grant Vortex external combi boiler should reduce their fuel consumption by at least 40% a year. Savings worth having I do believe.