Abstract: An apparatus and method for controlling the heating of an airflow. According to certain embodiments, the temperature of an outdoor heat exchanger and the speed of a compressor are used to determine a blower speed for a variable speed indoor air blower. The selected blower speed may facilitate a flow of air across a second, indoor heat exchanger at an indoor volumetric flow rate that heats the airflow to a leaving air temperature. The leaving air temperature may at least seek to attain the temperature of a variable target leaving air temperature that is adjusted based on changes in outdoor ambient temperatures. Additionally, according to certain embodiments, the blower speed may be based on an indoor volumetric airflow rate that is determined, at least in part, on a determined system heating capacity and a temperature at the outdoor heat exchanger.