Cold Climate Heat Pump Capacity at 5F: MAX Heating BTU by Model

It depends entirely on the model, which is why the per-model number matters. A dedicated cold-climate unit like the Mitsubishi P-Series Hyper-Heat (ducted) holds 38,000 BTU/hr at 5F, 95% of its 40,000 BTU/hr rated capacity at 47F. A mainstream unit falls off much harder. The MAX capacity at 5F is the number that answers "will it heat my house," and it is always shown here next to the rated 47F figure.

Rated capacity is the AHRI-certified capacity at the 47F rating point. MAX capacity is the most the unit can put out at a given outdoor temperature when it ramps up. The "will it heat my house at 5F" answer is the MAX at 5F, so every capacity on this page is labeled RATED or MAX, and the MAX at 5F is shown alongside the rated 47F number so you see both.

Because a percentage means nothing without its denominator. The Fujitsu AIRSTAGE XLTH (wall ductless) holds 23,200 BTU/hr at 5F. Against its rated 47F capacity of 24,000 that is 96.7%; against its MAX 47F capacity of 36,200 it is 64.1%. Both are true. This page always publishes both source BTU numbers and the chosen denominator, never a bare percentage. NEEP floors its stored percentage to a whole number; the computed ratio is shown here.

The balance point is the outdoor temperature where the heat pump's declining MAX-capacity curve crosses your home's rising heat-loss load line. Above it the heat pump covers the whole load; below it you need backup heat. Enter your design heat load and design temperature in the calculator and it reports the balance point plus the backup heat needed at design, as a readout. For example, the Mitsubishi P-Series Hyper-Heat (ducted) against a 45,000 BTU/hr load at 5F balances at 14.3F and needs 7,000 BTU/hr (2.05 kW) of backup at design.

Every capacity and COP figure is transcribed from the AHRI-certified NEEP cold-climate air-source heat pump (ccASHP) database, pinned to a specific AHRI certificate for each model, and confirmed against the manufacturer submittal. The interpolated capacity, the maintained percentages, and the balance-point readout are computed from those printed rated points. The manufacturer engineering data or a Manual-J load calculation by an HVAC pro has the final say.