Heating capacity at 5 degrees, against the 47 degree figure

HSPF2 is a single seasonal figure. It is useful for estimating a winter’s electricity, but it does not tell you the capacity the unit delivers at 5 F, which is the question of whether a room stays warm on the coldest mornings. Those are different questions and they need different data.

The ENERGY STAR Cold Climate specification is a widely available answer to the second question that comes with a published floor. For a non-ducted split it requires at least 8.5 HSPF2^[3] and 15.2 SEER2^[4], and for the Cold Climate designation a capacity at 5 F of at least 70 percent of the capacity at 47 F ^[1], and a coefficient of performance at that same temperature of at least 1.75 ^[2]. The criteria page also requires a controls verification procedure, to confirm the 5 F results are achieved by the unit’s native controls operating as they would in a customer’s home.

This is an ENERGY STAR Cold Climate certification minimum, not a model-specific capacity rating. The ordinary efficiency tiers used on this site do not establish a corresponding low-ambient capacity minimum, so this calculator prints no inferred fraction for them.

The draw column is the other half of the story. At a coefficient of performance of 1.75, delivering that reduced heat takes more electricity per unit of warmth than the 8.5 HSPF2 seasonal threshold implies (that threshold works out to a seasonal COP of about 2.5). The certification floor therefore describes both minimum heat output and minimum low-ambient efficiency. Your exact model and electric rate determine the actual draw and cost at that hour.

The six states below have the highest heating degree-day totals in the NOAA statewide series for 2025. If you are in one of them and you are being quoted equipment without the Cold Climate designation, the ordinary certification tier does not supply the low-ambient capacity minimum used on this page. Ask for the exact model's table at your local design temperature rather than inferring cold-weather output from the 47 F figure.

In every one of those states the heating side is more than 90 percent of this annual degree-day comparison (NOAA, calendar year 2025, a single year rather than a climate normal), so HSPF2 and model-specific low-ambient capacity deserve particular attention alongside cooling efficiency. Whether ENERGY STAR Cold Climate (non-ducted) is worth a higher installed price depends on the exact model, local design temperature, run hours, electric rate and backup-heat plan; this page does not calculate that payback.