HUNTINGDONSHIRE'S ground-breaking green scheme to demonstrate to residents how they can save both cash and emissions should go live next spring. The district council is the only authority in the country involved in a building research project to fit energy-saving devices to homes built in the 1960s and 1970s to prove how much can be saved. HDC has chosen that period of construction because extensive building in those two decades means those homes now make up the bulk of thermally-inefficient properties [modern homes should be built to higher environmental standards]. So the council has bought a semi-detached home in St Neots and a detached house in St Ives, which it plans to convert, use first as test-beds then as 'show homes' and then, after around three years, sell back into the market at what it hopes will be a substantial profit to Council Tax payers. The semi, in Manor Farm Road, St Neots, will have the most affordable improvements, such as a condensing gas boiler, water-efficient taps and fittings, a water-harvesting unit for toilet-flushing and other uses that do not need pure water, energy-efficient lighting, solar water-heating panels, thermostatic radiator valves, and well-insulated loft, wall cavities and floors.