What are the 4 Golden rules that passive solar houses and energy efficient houses have in commun in their orientation towards the sun so they hardly need any back-up cooling or heating system

To save your electric bill, you want to use the sun´s power to the maximum. You want to turn an energy efficient house towards the sun to collect as much heat as possible. The correct orientation is an essential element of an energy efficient house.

Design techniques of energy efficient houses have been around for many years already. The old Spanish haciendas were long houses, located in such a way that the longer walls faced the south to take in the heat of the winter sunlight.  In summertime, when the sun was high up, long verandas provided shade and kept the houses cool.

Rule_1. Largest wall facing south

Nowadays an energy efficient house is build according these same guidelines. If possible, the longest side of your house should be positioned from the east to the west. This means that the biggest wall is facing south and is capable of collecting the sun´s heat most of the day and when the sun is at its strongest. Just by constructing an energy efficient house according this principle and placing your windows correctly, you can reduce your total energy need up to 40%, without any additional expenses.

Rule_2. Heaviliy used rooms face south

In an energy efficient house the rooms that you use most should be facing south. Also the majority of your windows should be on the south-side for maximum heat gain. Next to your regular windows, you can also use other solar gain collectors, like clerestories and skylights. Clerestories have an additional benefit to regular windows: they allow the light to enter deeper into the house reaching the cold north wall as well. Skylights are often not as effective as they are often placed horizontally and don´t get a lot of sun in wintertime.  The shorter east/west side reduces the amount of surface area exposed to the sun and cuts down of heat gain.

Rule_3. Other Room on the north side

In an energy efficient house, rooms that don´t require as much warmth as your ´living areas´, like the garage, the laundry, the pantry and the staircases should be on the north side of the house. These rooms then also act as a barrier to keep the cold air from the north from entering the warmer living areas easily.

Rule_4. Evergreen trees should be planted at the north side of an energy efficient house to keep away the strong and cold winter winds.

Trees that drop their leaves in winter can be planted on the south and east or west and can shade your home in the summer.

Though orientation of an existing house towards the sun is difficult, energy efficient house design techniques apply smart reordering of rooms, adding solar windows for solar gain and certainly getting trees to provide shade or shelter, in order to keep the house from heating up in summer or loosing heat in winter. The payback time of these measures is good (though there are better ones in following articles on passive solar house and energy efficient house designs).