The MRCOOL MDPHK-20 Universal DC Inverter Packaged Unit Heat Kit 20KW is a high-capacity electric heating accessory engineered to provide supplemental heat for compatible MRCOOL Universal DC Inverter packaged HVAC systems. It works by converting electrical energy into heat, which is distributed through the unit's airflow to maintain consistent indoor comfort during colder conditions. ... https://www.partshnc.com/mrcool-dc-inverter-packaged-unit-20kw-heat-kit-mdphk-20