For collectors intended to operate in the upper end of the medium temperature range and in the high temperature range, selective absorber coating is worthwhile, because it reduces radiation losses significantly. The most effective selective coating available to date is black chrome, applied by a complex electroplating process over a nickel base. If applied on a material other than copper, the plating must be applied to both sides to avoid corrosion. Short cuts in the process to save materials or plating time have not been successful. Good black chrome plating on nickel base has proven stable and not susceptible to high stagnation temperatures or aging.
Selective collectors are particularly cost-effective for large installations for water heating.