How to Design a Passive Solar House

The principle of passive solar heating and cooling lies in the orientation of the house on the site and the strategic placement of structural elements, particularly windows. In accord with these factors, the design of a passive solar house is dependent on regional location, landscape design and the homeowner's specific needs. Passive solar heating, in and of itself, is the practice of using the sun's natural heat and the seasonal shifts to heat and cool a home without mechanical systems. For practical purposes, however, many solar passive designed homes have a mechanical system installed within the structure to serve as backup.

Instructions

1. Consider the overall climate of the region. In colder northern regions, passive solar design is dependent on direct heat gain from the sun in the winter. In warmer climates, the passive design should include indirect heat gain.

2. Plan the structural shape of the house. A home using solar passive heating/cooling should be designed to allow for full exposure to the south. The home, then, needs to be elongated and set on an east/west axis. This maximizes the southern and northern exposures and minimizes the east and west exposures.

3. Use a sloped roof to minimize heat loss. Slope the roof downward from the south to the north. In colder climes, the north side of the house can be built into a hillside to further reduce heat loss. In warmer regions, the slope need not be as severe.

4. Use glazed windows as a south wall. The sun follows south-side paths, so whether direct heat gain or indirect heat gain is used, the exposure must be southern. In colder climates, angled windows allow for more heat gain in the winter months.

5. Determine whether to use direct heat gain or indirect heat gain methods. Direct heat gain utilizes the interior of the home to convert the solar gain into thermal energy. The sun's heat is absorbed into the walls and floors and radiates outward into the interior.

   Indirect heat gain utilizes a convection process in which thermal storage is used. A storage system, such as a dark colored concrete wall is set between the south bank of windows and the interior of the home. The wall stores the solar energy, dispensing it only when interior temperatures drop below ambient temperatures.

6. Determine the materials for the interior and exterior of the home. For solar passive systems, concrete or block serve as excellent materials. These materials can store solar energy and disperse it without any mechanical assistance.

7. Consider appropriate landscaping. The landscaping should include only indigenous plants. Trees should allow for full exposure in the winter and provide shade in the summer. Gardens should be planted close to the south windows to absorb solar energy in the summer.

8. Expect to live in an open floor plan. Solar passive systems are dependent on exposure of the interior to the solar rays. Living spaces need to be open to the southern exposure. Bedrooms and bathrooms should employ clerestory windows and venting to allow for heating and cooling.

Tips & Warnings

• Consult an architect who specialized in solar design before investing in a site.