This Home Energy Brief focuses on space cooling. The Brief covers the issues of heat gain, passive cooling, and space cooling systems. Using a conventional air conditioning system is often the most expensive and energy intensive way to cool a home. If you are buying a new air conditioner, first consider reducing heat gain in your home through passive cooling measures and increasing ventilation with low energy fans. Then consider investing in more expensive cooling systems like evaporative coolers, heat pumps, and air conditioners. If you already have an air conditioner, properly maintain it so that it runs at peak efficiency. Always look for the Energy Star label when purchasing new cooling systems. The price tag may be a little higher than on non-Energy Star units, but you will pay off your investment every time you use the equipment. As of 2012, the Home Energy Briefs have been updated and adapted to Southern California Edison’s Online Home Energy Guide.