For 2026, MRCOOL’s 24 SEER2 and Zone Air’s 23 SEER2 come down to your winter...

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For 2026, MRCOOL’s 24 SEER2 and Zone Air’s 23 SEER2 come down to your winter needs: choose MRCOOL for value above -15°F, or Zone Air Hyper Heat for heating down to -22°F.