When designing any home-new or remodeled, environmental responsibility and a low impact on our resources should be the main concern. One way to reduce our carbon footprint and conserve our natural resources is through passive solar gain during the winter months and cross-breeze ventilation in the summer. This can be achieved through southern-facing window solar designs.
Southern-facing windows in any passive solar and cross ventilation design is basic energy-efficiency 101 (unless your from down under then your hemisphere requires north-facing windows). The reason is simple: The sun rises high on the horizon during summer months, keeping direct sunlight out of the windows. Just the opposite is true for the winter months. The sun spends a majority of its time in the southern sky and rides low on the horizon, allowing a more direct beam of UV light.
A well designed southern-facing window scheme can significantly cut down winter heating bills. This can be increased exponentially as other green renovations are added. For example, an underfloor heating system with a natural stone tile in direct contact with winter sunlight for over three hours, can heat an entire home during the day, saving a fortune on heating bills. And with the addition of natural stone, heat that is absorbed earlier in the day still radiates out long after the sun goes down, further increasing energy-efficiency and decreasing utility costs.
When warmer springtime and summer months roll around, southern-facing windows do double duty. By positioning French doors, sliding glass doors or other large openings on the northern side, cross ventilation increases, cooling down the house. Dormers, cupolas and bell towers further add to the green factor by increasing the natural flow of hot and cool air by allowing hot air to rise and escape, pulling in cool air behind it through southern-facing windows.
In areas where winter heating isn’t as big as an issue as cooling in the summer months, exposure to the southern sun can increase utility costs and decrease energy-efficiency. By changing the design and combining lower southern-facing windows, cross-ventilation and very wide roof overhangs together, southern-facing windows can be just as energy-efficient as their more northerly counterparts.
Every climate and building site is different, and caution should be stressed to the particular sites solar habits when designing any home with southern-facing windows. If possible, spend some time at the property during different parts of the day and possibly through several seasons to get a general feel of how the sun moves across the land. Take into consideration and trees, hills other sun blockers throughout the day before investing in a southern-facing window solar design.