Compact and space-saving, the VRV IV S-series systems are silent, so homeowners can enjoy the benefits of quiet operation. Precise temperature control allows every part of every room to be covered while, even under partial load conditions, these HVAC systems are extremely energy efficient. All 36,000, 48,000, and 60,000 Btu/h models run on single-phase technology to further reduce energy consumption. Plus, built-in diagnostics simplify maintenance and help ensure systems are serviced when needed.