The Efficiency+® 100 residential gas boiler is a high-efficiency, direct-vent unit designed for light commercial and residential use. The boiler has a standard two-stage burner that saves fuel by closely matching output to system demand; it also allows a longer burner-on cycle to maximize operating efficiency, the company says. With warmer outdoor temperatures, the boiler will use less fuel to maintain comfortable indoor temperatures, providing savings by reducing heat output 50%, says the company.

Lochinvar Corp., 2005 Elm Hill Pike, Nashville, TN 37210; 615-889-8900; 615-885-4403 (fax); (Web site).