Rhotech Solar manufactures low-cost solar collectors for heating water for homes and businesses. The design is efficient and low-cost to enable an estimated return on investment of less than five years. Rhotech Solar's design consists of two parts: a collector and a polymer heat exchanger. The collector is a flat and flexible panel approximately four feet wide and ten feet long, though collectors of any length are possible. The polymer heat exchanger is a set of thin-wall plastic tubes which are joined together at the ends to a single 3/4″ NPT fitting. The use of polymers keeps costs low and the unique design (using thin-films and thin-wall tubes) is able to overcome the relatively poor heat transfer characteristics.