For 2026, MRCOOL delivers 24 SEER2 efficiency, while Zone Air offers 23 SEER2....

https://xeon-wiki.win/index.php/Do_I_Really_Need_a_Disconnect_Box_for_a_Mini_Split_Condenser%3F

For 2026, MRCOOL delivers 24 SEER2 efficiency, while Zone Air offers 23 SEER2. The choice comes down to your winter lows: choose MRCOOL for value when temperatures stay above -15°F, or Zone Air Hyper Heat for heating down to -22°F.