MRCOOL offers 24 SEER2 efficiency and strong value above -15°F. Zone Air’s 23...

https://oliviamaids.com/can-a-multi-zone-diy-system-heat-and-cool-a-whole-house/

MRCOOL offers 24 SEER2 efficiency and strong value above -15°F. Zone Air’s 23 SEER2 Hyper Heat model keeps heating down to -22°F. The choice is simple: prioritize price in milder winters, or pay for extra cold-weather capacity.