Cold Climate Heat Pumps Now Maintain Full Capacity Below -15°F

The latest generation of cold-climate heat pumps from Mitsubishi (Hyper-Heating), Fujitsu (XLTH), and LG (Arctic Engineering) are now rated to maintain full heating capacity at -15°F and continue operating down to -22°F. Field data from Vermont and Maine installations shows that properly sized cold-climate heat pumps can serve as the sole heating source in Climate Zones 5-7 without backup, provided the building envelope is adequately insulated and air-sealed. COP at 5°F ranges from 2.2 to 2.8 depending on model.