Passive Solar House Plan

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Passive Solar Home Basics

Passive solar homes are designed with the right orientation, shape, windows, overhangs, ventilation, thermal storage, and other elements based on design, architecture and landscape principles.

A passive solar house can easily reduce its annual heating and cooling costs by 20 percent, 40 percent or more… And that with little or no additional expenses and without polluting: passive solar principles offer heating, cooling and lighting without contributing to global warming.

Passive solar designs

Passive solar design can be fully integrated when planning a new home. But it may be much more difficult to integrate passive solar principles in existing homes.

The existing orientation and shape of the building, or the existent windows and materials used in walls and in other parts of the house can be major obstacles to passive solar plans. Passive solar techniques are mainly a set of strategies to implement while projecting a new home.

Passive solar house plan

A passive solar house plan considers:

1- Passive solar heating strategies (related with elements as the shape of the house and its orientation relatively to the sun, or the adequate thermal mass and correct dimensions of its glazing elements).

2- Passive solar cooling strategies, based on elements as shading (through overhangs, trees, or devices as awnings), natural ventilation (cross ventilation, correct exposure and planning of venting and glazing elements) or reflective materials.

3- Passive solar thermal strategies for cooling and heating, based on the right and proportionate thermal mass and construction materials: materials may provide the right sun gains without overheating, or the appropriate cooling needs.

4- Other related measures and principles include appropriate colors (of the walls and roof…) and specific elements as sunrooms, wing walls, trombe walls, water walls, roof ponds, diffusing glazing materials, etc., etc.

Passive solar house plans: the role of design and architecture

Contrarily to active solar techniques (based on solar collectors), a passive solar house doesn’t presuppose any particular devices. It’s mainly a question of design, landscape, materials, walls, windows… with a central goal: get the right amounts of shade, ventilation, heating or cooling…

That doesn’t mean, obviously, that solar panels or fans, or other devices, shouldn’t be used. They may be are useful and advantageous in many cases, or even indispensable. An example: fans are indispensable in hot humid climates, where you can’t fight humidity through natural ventilation or other passive solar house principles…

Passive solar house plans and climate

Most of the passive solar designs are geared towards heating and cooling in temperate and dry climates or in cold climates.

There are some general principles either applicable in cold, temperate or hot and tropical climates: properly sized overhangs, principles of home's thermal and storage mass, appropriate shading through trees…

There are, anyway, different passive solar means, very specific of some climates. In hot and humid climates, we should use some particular techniques:

- use of vertical glazing;
- orientation of the house to avoid the direct impact of sun (in very hot climates);
- use of verandas and shade nettings;
- impossibility of controlling the humidity without mechanical devices;
- …

Climate determines the final passive solar techniques, and your house’s plan should reflect it. Many of the techniques are universal, but their specific configuration and importance may vary a lot, according with the particularities of each climate zone. Take into account, namely, the differences between 1) passive solar heating and 2) passive solar cooling principles and techniques.

Solar Energy Industries Association
www.seia.org