Engineers at the US,based National Institute of Standards and Technology have developed a photovoltaic solar water heater that does away with the plumbing, replacing it with a wire that carries the electricity generated by the photovoltaic panels on the roof down to the hot water heater. Since solar thermal water heaters heat water directly by piping it through rooftop panels, the new technology of converting sunlight into electricity could lead to cheaper domestic solar energy. The price of such heaters may eventually he less than half that of today's solar water heaters since the plumbing expenses are done away with.