Lennox Parts Plus 9301 Gaither Road Gaithersburg MD 20877 is a wholesale supply house of HVAC parts equipment and supplies. Areas Served: Lennox Parts Plus has HVAC supply house locations throughout the United States. What Brands Does Lennox Parts Plus Sell? Lennox Parts Plus carries name brands like Lennox Honeywell White Rodgers Rectorseal Nu-Calgon Diversitech Copeland and many other HVAC supplies.