For 2026, MRCOOL’s 24 SEER2 is the value pick for temperatures above -15°F....

https://mighty-wiki.win/index.php/What_Tools_Do_I_Actually_Need_to_Install_a_DIY_Mini_Split%3F

For 2026, MRCOOL’s 24 SEER2 is the value pick for temperatures above -15°F. Zone Air’s 23 SEER2 trades a point of efficiency for Hyper Heat down to -22°F. Choose based on your winter lows.