Solar collectors can be installed anywhere that the sun will shine on them all year but are usually mounted on roofs to receive maximum exposure and to be out of the way. Collectors should face within 20° to 30° of due south, but up to 45° east or west of south may be acceptable for some systems.
The "tilt angle" of the glazing should be within 15° of the latitude where they are located, which ranges from roughly 25° near the southern border of the continental United States to approximately 50° at the northern border. Higher "tilt angles" are preferable for systems used year-around. In determining the tilt of a Collector, remember to compensate for the tilt of the roof. A slope of 4-in-12 equals 18 and 1/2°.
The collectors for any type of solar water heater should be located as close as possible to the conventional water heater to minimize the connecting piping. Heat loss occurs as warm water moves through the pipe, so keeping the distance to a minimum reduces heat loss.
Thermosiphon and active collectors are usually located on the roof, but they can be attached to supports on the side of a house or on the ground. Because batch water heaters combine collectors and storage tanks, they are heavy and are usually mounted on the ground. However, if adequate structural support is provided, they too can be placed on the roof.