Velux

Designed to replace or add to an existing water-heating system, the company's solar hot water heating system can provide up to 100 percent of the demand for hot water heating, says the firm, with typically 80 percent of hot water needs coming from free solar power. The SRCC-certified solar energy roof collectors are designed to integrate well with roof lines, the company says, and they integrate seamlessly with roof windows. 800-888-3589. www.veluxusa.com.