Application to the home

The implementation of solar passive elements in your home depends on the location and orientation of your home. Best results are obtained if:

• your home is being designed or constructed as the building can then be orientated and designed to maximise solar gain in winter and minimise solar gain in summer
• living rooms face south or west allowing direct access to solar gain during winter months
• ability to reflect or cut off solar gain during the summer in southern Europe by adding passive building elements
• doors and windows can be positioned to encourage natural ventilation between hotter and colder parts of the building
• ability to replace existing windows by vented windows or with glass coated with reflective layers to retain heat
• can add on external glass pane to a south facing wall to form a Trombe wall

Suitable shading can provide good indoor climate control thereby avoiding air conditioning during the summer whilst helping retain heat during the winter. The basic principle is to place the shading so as to reduce the solar radiation during summer.

The following are the most common options.

• deciduous trees shading south facing windows - leaves provide shade during the summer but fall down in the autumn
• shutters generally mounted outside a window; eflect sunlight falling on the window during the summer and retain heat during the night in winter
• blinds comprising slats which can be inclined to control light and reflect heat: may be mounted either horizontally (Venetian blinds) or vertically
• external horizontal surfaces mounted above the window to cut off direct solar rays when the sun is high in the sky but allows entry when the sun is low in the sky
• awning - an external blind that can be extended or retracted depending upon the need to reflect sunlight
• shading panels, flat or tubular, that can be used to shade facades or terraces

Solar heating

Absorption of solar rays by an external, south-facing wall allows heat to be conducted through to the inner wall of the dwelling.

Transmission of light through windows allows infra-red rays to heat the air in the room by convection. If the external window pane is coated with a suitable reflective layer on the inside, then the infra-red rays are reflected back into the room so retaining the heat.

Trombe wall

Black or dark wall that uses the greenhouse effect with a glass placed a few centimetres in front of it to form an air space; air is naturally circulated through differential heat flows.

Vented windows

A vented window comprises a Venetian blind within a double glazed window. The leaves of the blind are coated black on one side and white on the other enabling heat to be either absorbed or reflected. There are openings both to the outside and inside which enable warm air to either enter or leave the room space.

Natural ventilation

This is an effective way of removing hot air from the interior of buildings using methods such as natural breezes, air temperature differences or the effect of chimneys. In some cases hot dry air can be being cooled and humidified by small scattered fountains.

Effects of climate

In southern Europe the key concern is to keep the building cool during the hottest part of the day during the summer months. However buildings will need to absorb heat during the winter months even though the winter period is relatively short.

In northern Europe, the greatest need is for maximising the solar gain during the long winter months. During the shorter summer months, natural ventilation should be sufficient to cool the building without the need for any active means.

Cool sunny winters are ideal for the implementation of vented windows or Trombe walls. In hot summers high heat inertia will reduce peak temperature. The effects of high solar incidence in hot summers can be reduced by using shading or vented windows.

Holistic solutions involving passive solar architecture can be used to enhance the aesthetic quality of the building as well as the comfort level of the occupants e.g. window shutters on white washed buildings.

Environmental impact

This is negligible as only passive energy flows are used. Visual impact can be minimized through suitable attention to architectural design.

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