The Lennox XP20 is a high-efficiency heat pump with true variable capacity, meaning it can adjust heating and cooling output to perfectly match your comfort needs to your energy use. This also helps control humidity with exacting precision. With a SEER of up to 20.00 and an HSPF of 10.00, the XP20 uses energy extremely efficiently without sacrificing comfort. This product has been designated as one of the Most Efficient ENERGY STAR certified products in 2017. Powerful performance doesn’t have to mean disruption. The XP20 is designed with smart features that let it operate at comfortable sound level - as low as 65 decibels! When connected to a compatible Lennox iComfort® S30 thermostat, the XP20 can also adjust humidity based on where you live, so you get comfort customized to your environment.