Another large factor in energy consumption is consumption by buildings. It is relatively easy to create rules for the energy consumption of new buildings, but since the lifespan of most buildings is often decades, it is important that older buildings are considered as well. Retrofitting older buildings so that they come up to current standards is often expensive, but the technology to make buildings (almost) energy neutral exists already today. It is important that policy regarding buildings is clear for years ahead, so it is possible to anticipate extra costs when building or renovating buildings.