Short Answer
It is a shingle designed with features intended to reduce visible algae growth under specified conditions.
Detailed Explanation
Algae-resistant shingles contain copper or zinc granules embedded in the shingle surface. When rainwater runs over these granules, it releases small amounts of copper or zinc ions that inhibit algae and moss growth. This helps prevent the dark streaks and stains that algae causes on roofs, particularly in humid, shaded areas common in South Jersey. While algae-resistant shingles don't guarantee a completely algae-free roof forever, they significantly reduce the rate of algae growth and the need for roof cleaning. For homes in shaded, humid, or coastal areas, algae resistance is a valuable feature.
Why It Matters
Algae growth causes dark streaks that affect appearance and can reduce shingle life. Algae-resistant shingles are particularly valuable in humid, shaded South Jersey environments.