Direct gain and thermal mass are two of the basic concepts behind passive solar design. By using solar heat in the daytime and storing some for the evening, a home can be heated by the sun. The balance between direct gain and thermal mass, along with the energy efficiency of the house, will determine how much of the home's total heating requirements can be filled by solar energy. When building a new home or remodeling an existing one, consult a solar designer to assess the passive solar potential. A few passive solar techniques include enlarging the window area on the south wall, or adding thermal mass inside by installing an adobe banco or a brick floor.
Heat is stored in the wall during the day and it radiates into the room at night.
It is not necessary to provide ventilation holes for the wall to work properly. Landscaping is also useful in using the sun's energy. Evergreens planted on the north side of a home provide a windbreak to cut cold winter winds. Deciduous trees can be planted to the southwest to cut the late afternoon sun in the summer. Some sun will penetrate the bare branches in the winter.