Cold-Climate Heat Pump Capacity & COP Derating Calculator
Calculate heat pump heating capacity retention (BTU/hr), low-temperature COP, and electric auxiliary strip heat requirements at sub-zero temperatures (47°F down to -15°F) per NEEP and AHRI 210/240.
Heat Pump Specifications (AHRI 47°F Baseline)
BTU/h
e.g., 36,000 BTU/h (3.0 Ton System).
COP
Typical modern inverter: 3.6 to 4.2 COP.
°F
e.g., 5°F or -5°F 99% ASHRAE winter design.
Building Heat Loss & Utility Rate
BTU/h
From Manual J calculation.
$/kWh
Cold-Climate Performance Verdict
76.8% CAPACITY RETENTION
Delivered Heat @ Design Temp
27,630 BTU/h
76.8% of nominal 47°F rating
Operating COP @ Design Temp
2.10 COP
210% efficiency vs resistance
Heat Pump Compressor Power
3.86 kW
Electrical draw during operation
Auxiliary Strip Heat Required
0.69 kW
2,370 BTU/h deficit to meet loss
Operating Economics & Cost Comparison
Total System Heating Cost:
$0.82 / hour
Baseline 100% Electric Resistance Cost:
$1.58 / hour (8.79 kW)
Hourly Heating Savings vs Resistance:
$0.76 / hr saved (48.1% less)
NEEP ccASHP Specification Criteria
Building Decarbonization
NEEP cold-climate heat pumps must maintain at least 70% of their 47°F rated heating capacity at 5°F outdoor temperature with a COP of at least 1.75. Inverter vapor-injection compressors maintain high mass flow of refrigerant even in sub-zero ambient air, minimizing electric resistance backup.