Heat Pump COP Product Comparison

Heat Pump COP Product Comparison Field Guide

Why product comparison at design temperature matters

The AHRI 47F COP rating is tested at a mild temperature that many cold-climate homes rarely see during peak heating season. In Bismarck, Minneapolis, or Denver, the hours that drive your electric bill are the ones at 0F, -10F, and colder. A heat pump rated COP 4.0 at 47F might outperform a competitor at 47F but underperform it at -13F where it matters most for your bill.

The NEEP cold-climate heat pump product list measures performance at 5F and -13F specifically for this reason. This calculator shows you both products at each published rating temperature so you can make the comparison at the temperatures relevant to your climate.

Common mistakes when comparing heat pumps

Comparing HSPF (Heating Seasonal Performance Factor) ratings across two products without verifying what climate zone and operating temperature range those HSPF numbers assume. HSPF is a seasonal average weighted toward milder temperatures and can favor products that are less efficient in extreme cold.

Using COP at 47F as the primary comparison metric when your design temperature is below 17F. The product rankings can reverse at low temperatures.

Ignoring the 5F rating point. The NEEP 5F threshold is the most useful single-number comparison for homes in ASHRAE climate zone 6 or colder. A product that barely meets the NEEP minimum (COP 1.75 at 5F) and a product that achieves COP 2.3 at 5F are in different performance categories even if their 47F COPs are similar.

Two worked examples using the comparison above

The numbers below come from running this calculator's own comparison formula, not from estimates written separately from the tool. They show why comparing two products only at the AHRI 47F rating point can point you to the wrong equipment.

Take the Mitsubishi Hyper-Heat H2i (M-Series) against the Fujitsu RLS3H Series, the calculator's two default selections. Using this calculator's product data, at every rating temperature from 47F down to 5F, Fujitsu shows the higher COP by a consistent 0.1: 3.9 vs 3.8 at 47F, 2.9 vs 2.8 at 17F, 2.3 vs 2.2 at 5F. A buyer who stops reading at the 47F number would pick Fujitsu. But the two curves cross between the 5F and -13F anchors, because Mitsubishi holds up better at the coldest end of its range in this comparison (1.9 vs 1.8 at -13F). Run the comparison at -10F, close to Minneapolis's 99% winter design temperature, and the calculator's linear interpolation between the 5F and -13F anchors puts Mitsubishi at COP 1.95 against Fujitsu's 1.88, a 3.7% swing toward the product that lost every warmer-weather comparison. These figures are estimates designed to guide comparison, not a substitute for the manufacturer's own certified rating sheet; field performance varies.

Push the same two products further, to -22F, close to Bismarck's design temperature and colder than either product's -13F rated floor. Both products clamp to their -13F value (1.9 and 1.8), and the calculator adds a warning: "Your design temperature (-22F) is below the rated range of Mitsubishi Hyper-Heat H2i (M-Series) and Fujitsu RLS3H Series. Comparison at this temperature is an extrapolation from published ratings and may not reflect actual performance. Consult manufacturer engineering data." Mitsubishi still leads by the same 0.1 COP margin, a 5.6% advantage, but the calculator is telling you plainly that neither product has been tested down there. That warning is a starting point for a conversation with a contractor, not a substitute for one.

How to use this comparison

Start with your 99% heating design temperature, the coldest hour your system has to handle in a typical winter, not the coldest hour on record. Your HVAC contractor can pull this from ASHRAE climate data for your city; common references are roughly -22F for Bismarck, -10F for Minneapolis, and 0F for Denver. Select two NEEP-listed products from the dropdowns above and click Compare Products. The primary result names the product with the higher interpolated COP at your design temperature and the percentage advantage; the four-point table underneath shows both products at every standard rating point so you can see whether the advantage holds at milder temperatures too, or only shows up at the extreme.

Watch for the extrapolation warning. It appears whenever your design temperature falls below a product's lowest rated temperature in this comparison, which for most cold-climate products on this list is -13F. When it fires, treat the comparison as directional rather than final, and ask the contractor bidding your job to point you to manufacturer engineering data for performance below that range.

What this comparison doesn't account for

The four-point table compares COP, not capacity, and COP is only part of the sizing picture. At extreme cold, a heat pump's heating output drops along with its efficiency, a separate effect this calculator does not model. It also does not adjust for multi-head mini-split systems, where an individual indoor head's COP can differ from the whole system's COP, for ducted versus ductless performance differences under the same AHRI certification, or for installation-specific factors such as an undersized line set, incorrect refrigerant charge, or restricted airflow, all of which can pull real-world performance below the published anchor values. Equipment age and maintenance state are not modeled either; a five-year-old unit with a dirty coil will underperform its rated curve regardless of which product wins this comparison. The calculator is also limited to design temperatures between -30F and 60F and to air-source equipment; ground-source and water-source heat pumps use a different rating framework entirely.

None of that makes the comparison wrong. It makes it a starting point. For a permit-required system design or final equipment selection, a licensed HVAC contractor will run a full ACCA Manual J load calculation against manufacturer engineering data specific to your house.

Sources

Every product COP value in this calculator is drawn from manufacturer specifications and published product data, primarily the NEEP Cold Climate ASHP Product List and ENERGY STAR's qualified cold-climate product data. Treat the comparison as an estimate designed to guide your shopping: published figures can change as manufacturers update listings, and actual field performance varies by installation. The full citation list is below.