Research suggests that heat pumps could cut household energy use and greenhouse gas emissions, but the costs are still high.
An air-source heat pump, such as the outdoor portion of the ductless heat pump pictured, takes heat from the outside air, runs it through a refrigeration cycle to step up the temperature (just like a fridge, but in reverse), and delivers it to a building. Photo courtesy of Tom Marsik
Three and half billion people in developing countries make for a vast and mostly ignored market, say Paul Polak and Mal Warwick. In their book, The Business Solution...