MRCOOL 15 KW Universal Air Handler Heat Strip with Circuit Breaker - MHK15UMRCOOL 15 KW Universal Air Handler Heat Strip with Circuit Breaker MHK15U Provides Emergency Heat for your MRCOOL Universal Air Handler. MRCOOL Heat Kit is the compatible heat kit model for MRCOOL MDUI18048 and MDUI18060. The MHK15U is capable of 50,001 55,000 BTU of heating capacity to keep you comfortable through the winter months. FEATURES: MDUI18024 is compatible with the 5 kW, 8 kW and 10 kW heat kits MDUI18036 is compatible with the 5 kW, 8 kW