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Lobby Three-Season Heliodon

Balancing Sun and Shade

Architects are often faced with decisions that affect patterns of sunlight striking their buildings. In the cold winter, solar energy can contribute free heat to a house and lower you energy bill.

At other times, particularly in late summer and early fall the sun can cause your house to overheat and shading is the best option. The variables of orientation, landscape and roof overhang can be maniputlated to produce a balance of sun and shade.

To demonstrate the shading effects of design, landscape, and orientation, this model has a rotating home with an adjustable overhang, a tree, and spotlights that simulate the position of the sun during three seasons of the year.

Winter afternoon (December, 1 P.M.)

The winter sun is low in the southern sky. A south-facing wall receives sunlight all day; a west-facing wall only receives half a day's worth; a north-facing wall receives none at all. Trees on the south side of a house block the low winter sun, especially if they are evergreens; even deciduous bare branches can cause significant reductions in solar heat gain.

Summer afternoon (June, 12 P.M.)

The summer sun is high in the southern sky, almost overhead. The overhang, if extended, blocks the sun; shade trees do the same -- but avoid planting them where they will keep the low winter sun out of your south-facing windows.

Late Summer afternoon (September, 4 P.M.)

The late summer/early fall sun is low in the western sky during the afternoon. Horizontal roof overhangs will not block the sun at low angles. Trees provide shade without necessarily blocking views. A porch or trellis could do the same.

For more information about heliodons visit our Heliodon Studies (PDF, 116 KB) fact sheet.