If you are building your home you have several choices to choose from regarding your heating source. If you choose to heat from the sun you need to build your home facing in the direction that the sun rise's. This allows your home to get the most sunshine during the hottest part of the day. Buying solar powered glass windows allow the sun to come through and stay in the home without escaping back out. After the sun goes down your home is kept warm by the sunlight that came into the home during the day. You need to keep the door shut in order to keep the heat in and you also need to use insulated curtains on the windows at night so that the heat will not escape at night while you sleep. Make sure you don't allow too many windows on the side of the house that faces the evening sun as it may cause the home to cool down quickly.