Money Saving Operation Our model 697C heat pump includes the AeroQuiet System. The AeroQuiet System keeps the sound levels of the model 697C down to 7.2 decibels, making it one of the quietest heat pumps available. As part of our exclusive AerocousticSM design, the AeroMax™ opening guides air steadily through the unit. The improved air flow enables us to incorporate a lower speed fan and fan motor, which delivers more consistent comfort with less noise and reduced energy use. We also wrap the compressor in a sound shield to blanket operational noise. These design elements minimize the operational noise so you can relax in quiet, soothing, economical comfort. 1. Scroll Compressor Is the heart of your heat pump system. It's smooth, reliable operation is the key to year-round comfort. 2. Sound Shield  Wraps the compressor to absorb operational noise for quieter performance. 3. Reversing Valve Shifts heat pump from cooling mode to heating mode and back again for reliable comfort season after season. 4. High And Low Pressure Switches Are built in to protect this unit's compressor. These switches monitor pressure in the system, adding to the reliability of the unit. 5. Discharge Muffler Ensures quiet performance by minimizing pulsations in the refrigerant line. 6. Heavy-Duty Coil Protection With DuraGuard™ helps avoid damage from rocks and other debris to keep the unit running efficiently.