Sears, The Home Depot, ACWholesalers.com and Amazon.com all sell wall-mounted heat pump units. Most brands have manufacturer warranties, and Sears offers purchase options for extended warranties and service plans.
Sears and The Home Depot have delivery, installation and customer training services available, for an additional fee. Through-the-wall units have to mount on an exterior wall and vent the unwanted air, either hot or cold depending upon the setting, through the wall to the outside. Mini split units have the compressor and condenser installed outside and the air handler unit place on any wall desired inside. Mini split heat pumps require no interior ductwork, and most units can feed up to four wall-mounted air handlers.