New Lennox XP21 heat pumps can be purchased from any number of independent Lennox dealers located through the United States and Canada as of 2015. The company's website has a full list of dealers and also a search function where users can find local dealers based on their ZIP code.
The Lennox XP21 is rated by some as one of the best heat pumps on the market and is the quietest and most efficient model available as of 2015, based on the Air Conditioning, Heating and Refrigeration Institute's standardized testing. The model is Energy Star-qualified and was named as one of the Most Efficient of Energy Star in 2014. With a seasonal energy efficiency ratio of 19.2, Lennox claims the XP21 to be nearly twice as efficient as a standard heat pump.
This model comes with the SunSource Solar-Ready option, which allows users to convert the heat pump into a solar-powered system. It can be connected to Lennox's iComfort Wi-Fi thermostat, which enables the unit to automatically make adjustments for optimal efficiency and performance. The XP21 also features a dual-fuel capability that allows it to be connected to a gas furnace. The unit is available in several sizes, including 3-ton/36,000 BTU and 4-ton/48,000 BTU models.