The world's first Active House stands at the crest of an estate. Its south-facing roof is covered in solar panels and solar cells, which between them harness more than enough power to keep the occupants warm and the appliances running. In around 30 years' time, if designers have got their sums right, the excess electricity flowing from the house into Denmark's grid will have cancelled out the energy costs of building it, leaving a non-existent footprint on the earth's resources.
Solar Tiles v Solar Panels: "Tiles, technically speaking, are photovoltaic cells that mimic traditional roof shingles. They first became commercially available in 2005; at that time, they were more expensive than panels, but recent market forces have driven down the cost, so now the prices are equivalent." - that's in the US, of course. | Century Roof & Solar