Is Solar Water Heating Right for You?

Determine the solar resource of your site.

How many hours of direct sunlight does my site receive? If your site is without shade and generally faces south, it's a good candidate for a solar water heating system.

Determine the estimated collector area.

A general estimate is about 20 square feet (2 square meters) of collector area for the first resident. For each additional person, add 8 square feet (0.7 square meters) if you live in the southern United States or 12 to 14 square feet if you live in the northern United States.

Calculate the estimated tank storage volume.

A small (50 to 60 gallon) storage tank should be sufficient for one to three people. A medium (80 gallon) storage tank works well for three to four people. A larger tank suits four to six people.

In active systems, the size of the solar storage tank increases with the size of the collector. The typical sizing is 1.5 gallons for each square foot of solar collector. This set-up prevents the system from overheating with lowered hot water demand. In warm, sunny climates, the ratio can be increased to 2 storage gallons per square foot of collector area.

Mark dimensions of collectors as well as plumbing and control arrangements.

How will my solar collectors attach to the roof? Will I use a structural attachment through the rafters? Is this placement elevated enough to allow for proper drainage to prevent debris buildup and roof rot?

Consult with your community to ensure compliance with covenants, building codes, historic district regulations, and flood-plain provisions.

Before installing a solar water heating system, you should investigate local building codes, zoning ordinances, and subdivision covenants, as well as any special regulations pertaining to the site.

A building permit is often required to install a solar energy system onto an existing building.

Potential zoning issues include obstructing side yards, constructing unlawful protrusions on roofs, or installing the system too close to streets or lot boundaries.

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