An optimum number of covers must be found. Two covers are best for home collectors while one cover is sufficient for livestock housing. Another way to improve efficiency is by selecting the best absorbing surfaces. An absorber can be treated chemically so that it will absorb most of the radiation striking it without re-radiating much of the absorbed heat out to the surroundings. This treatment is fairly expensive, but it increases efficiency when you need higher temperatures.
Reflectors can also increase the amount of radiation striking the collector face.
Weigh improvements in efficiency against the increase in cost and maintenance requirements of the system. Usually, the more efficient a collector is, the more costly it is. A less efficient but also less costly collector may prove to be more cost-effective in delivering a given amount of heat. As new design, manufacturing and installation developments occur, the relative cost effectiveness of alternate collectors will undoubtedly change. Collector construction Solar collectors are being made of many different materials and in a wide variety of designs.