The type of louvre system, described in two ways. First, whether the louvre system is vertical or horizontal. Second, which way the louvres tilt.

For vertical louvre systems, the tilt of the louvres is described as tilted up or down from horizontal:

For horizontal louvre systems, the tilt of the louvre is described as tilted toward or away from the building (or wall, etc.):

(If a horizontal louvre system is free-standing, just pretend it's attached to a wall at one end for the purpose of indicating orientation and louvre type.)

For exactly horizontal louvres, select either "up" or "down" and set the louvres tilt to zero. For a vertical system with exactly vertical louvres, select either "toward" or "away" and set the louvre tilt to zero.

The cross-sectional depth of the louvres.

You can use any units for the louvre depth— millimetres, centimetres, metres etc.—as long as you use the same units for all louvre measurements.

The cross-sectional thickness of the louvres.

You can use any units for the louvre thickness—millimetres, centimetres, metres, etc.—as long as you use the same units for all louvre measurements.

The spacing of the louvre (shown here for vertical louvere systems...for horizontal systems, it would be the horizontal spacing between the louvres).

Note that the spacing is measured from the center of one louvre to the next, not the spacing in between two louvre.

You can use any units for the louvre spacing— millimetres, centimetres, metres etc.—as long as you use the same units for all louvre measurements.

For vertical louvre systems, such as window blinds, the tilt of the louvres in degrees from horizontal:

For horizontal louvre systems, the tilt of the louvres in degrees from vertical:

The tilt should be between 0 and 90 degrees. Use the louvre type input to indicate whether the louvres tilt up or down from horizontal (for blinds), or toward or away from the building.

Entering the latitude value

Please enter your geographical latitude in decimal notation, such as "42.5" (don't include the quotation marks in the input field). The value should be between 0 and 90 degrees, although horizontal overhangs are typically only effective for temperate latitudes (24 to 60 degrees).

Use the North/South drop-down menu to indicate North or South Hemisphere.

Finding your latitude

By default, the analysis depicts the degree of shading by the darkness of the data cells, but you can select to have the numerical percentage of sun or percentage of shade listed as well.

If you select "Sun %", each data cell will have the percentage of sun listed, in addition to the background color as an indicator. The Sun % is in 10% increments. A value of "70%", for example, indicates that the shading provided by the louvre system is about 30%, and 70% of the incident sunlight gets through.

If you select "Shade %", each data cell will have the percentage of shade listed, in addition to the background color as an indicator. The Shade % is in 10% increments. A value of "70%", for example, indicates that the shading provided by the louvre system is about 70%, and 30% of the incident sunlight gets through.

This is the compass direction that the louvre system faces. You can select one of the eight cardinal directions (North, Northeast, etc.), or 10-degree increments in between.

For example, "10° E of S" means that the louvre system faces 10 degrees East (i.e. counterclockwise) of due South.

For vertical systems, this is the direction that the window faces. For horizontal systems, this is the direction that the wall faces to which the louvre system is attached. (If a horizontal louvre system is free-standing, just pretend it's attached to a wall at one end for the purpose of indicating orientation and louvre type.)