Roof Overhangs For Passive Solar

Because the sun travels different paths across the sky in the winter low and summer high time an overhang can be constructed to utilize and manipulate the heat energy from the sun.

Roof overhangs for passive solar.

For instance several features of a window will influence gain of solar heat and shade. How roof overhangs or other window overhangs work to control heat and solar gain overhangs are most effective for south facing elements in the northern hemisphere and at midday. 24 dec 2012 02 45 pm. An overhang or some sort of solar control or solar shading is a crucial element in passive solar design because it blocks the sun s heat energy when it is not desired.

Here s a link to a free web based tool to help you size roof overhangs on a passive solar building. Of course we don t want to solar shade either unless intentionally. Jonr senior member posts 5341. There is simulation software like sam to do this if you want even site phone apps we use it to design solar panels systems.

You can use the free software sketchup to draw the house and it will draw sun shadows for any date time at your location. I also urge you to read this article. We design them primarily to shed water away from the foundation wall depending on wind direction orientation etc. The size of the window width and height and the window s relationship to the roof the space above the window influences the direct and indirect gain of solar heat.

Borst passive solar roof overhang design calculator. How roof overhangs work. Design the roof overhangs generally passive solar design requires overhangs that are sized to fully shade the south facing windows on the summer solstice june 21 and to allow full sunlight to enter on the winter solstice december 21. In passive solar home design exterior roof overhangs provide a practical method for shading building elements such as windows doors and walls.

We don t design overhangs primarily for passive solar these days old design rules no longer apply. Design solar altitude angle for full sun deg from passive solar altitude angle calculator build height of roof overhang from top of glass feet or leave blank build depth of roof overhang from glass feet or leave blank requested solution 0 full shade full sun 1 full shade 2 full sun. Overhangs are most effective for south facing elements in the northern hemisphere and at midday. 18 24 is a good rule of thumb i use 24 w a energy heel.

User 757117 jul 16 2012 05 54pm 3. Borst engineering construction llc competence integrity and professionalism are integral to all that we do. In passive solar home design exterior roof overhangs provide a practical method for shading building elements such as windows doors and walls.