The types of potentially qualifying systems or system components include: Geothermal heat pumps, high efficiency chillers (generally 0.4 kW/ton or lower). Chilled beams. Condensing boilers with efficiencies greater than 90%. Energy recovery units. Water side economizers. Cogeneration (not common, but advantageous if available). Instantaneous hot water heaters. Heat exchangers taking advantage of high efficiency boilers to provide service hot water. High efficiency motors with VFDs. If HVAC upgrades are being considered, a full system retrofit is almost always required.