After removing the kickboard under the cabinets, you can slide this mat into the cavities to allow for direct heated airflow. The legs of this mat are perforated.
PTC Fan Heater Cirrus 40 (60-230W)
HP06 Surface Heater
PTC Fan Heater Cirrus 80 (300-800W)
Thermostats - Adjustable
PTC Fan Heater Cirrus 25 (5-40W)