Yes, Shingle Shield will work on new shingles. It will help prevent organic growth as well as reduce granular loss. Always verify use with your shingle manufacture to not void the warranty.
Under normal conditions, Shingle Shield should last up to 5 years. It is recommended to apply another coat after 5 years to provide optimum protection.
Optimum temperature at application is 80°F. Excess heat effects the speed of the curing as well as cool temperatures slow the curing process. It is not recommended to apply when temperatures are lower than 40°F and higher than 100°F.