Passive Solar Homes

What if someone told you that you could use just sun and some specific technologies for heating or cooling your house? The passive solar house concept which is becoming more and more popular does exactly this.

Passive solar homes are designed to get their heating and cooling needs from the sun, wind, trees, or from the windows and the materials used on the walls and roof of the house and the way they interact with the environment. In short, as the name implies, you do not need to actively heat the house with these systems.

These systems intend to eliminate the need for boilers, heaters and cooling systems.

Technologies in Passive Solar Heating and Cooling

Passive solar homes use the followings to meet your heating or cooling needs:

- thermal storage or reflectance of the materials used in their walls, floor and roof;

- building's sun exposure (which depends on its shape, orientation and layout)

- natural ventilation (which depends on windows, windbreaks, orientation)

- proper shape and orientation of the house

- advanced windows, skylights and venting elements

- appropriate colors (of the walls and roof in order to effectively reflect or absorb light) and specific elements as

sunrooms,wing walls, trombe walls, water walls, roof ponds, diffusing glazing materials;

- other elements dependent on design, architecture and landscaping.

In other words, passive solar homes use a set of passive solar heating techniques and passive cooling techniques.

Passive solar techniques are mainly a group of designs to implement while you are projecting a new home.

It's impossible to apply most of them on existing homes: you can't change the orientation and shape of a home, or the materials used in their walls. However, depending on the stage of your house (built or to be built) you can choose among them to most effectively turn your house into a passive solar house.

The Use Of Mechanical And Active Techniques

The aim of solar passive cooling and heating is to get a natural cooling and heating which wouldn't collide with the use of "active" techniques such as fans or solar water heating.

You would have to use them in some cases.

For example fans are indispensable in hot humid climates, where you can't fight humidity through natural ventilation or other passive principles.

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

Tthere are, of course, some general principles applicable in every climate: properly sized overhangs, principles of thermal and storage mass and reflectance, shading through trees but some principles or measures are very specific to some climates.

The shading of trees can't be used extensively in cool and cold climates.

That strategy should be analyzed with extreme care, according to specific micro climes and climate conditions.

On the other hand, in hot and humid climates you have to use some particular techniques, that is not used in cold climates:

- orientation of the house to avoid the direct impact of sun, instead of the opposite;

- extended use of verandas and shade nettings; 

- intense use of mechanical devices to control humidity, etc.

Each climate determines the final passive solar techniques, and your plan should reflect it. Some of the techniques are universal, but others are specific to some microclimates and climates zones.

Although not the most popular among "green" technologies, passive solar houses will be more common in future as researches about them increase and the drawbacks are eliminated to the highest possible level.