A house with AC in a hot climate should be painted white (or covered with mirrors) to reduce absorption of light from the hotter sun and surrounding objects. That seems obvious. But what should cover a house in a cold climate? The house interacts with a system that is hotter than it (the sun) and a system that is colder than it (its immediate surroundings), so the analysis is more complicated. In order to minimize losses to surrounding objects, the paint should be a poor emitter of infrared. In order to maximize absorption from the sun, the paint should be a good absorber of visible light (black). I'd like to know a few things to answer my question. 1) Which effect is generally more important, absorbing as much visible light as possible or emitting as little infrared as possible? 2) Is it possible for a material to simultaneously be a good visible absorber and a poor infrared emitter? If so, could you give a specific example?