A different incumbent, a different answer

Every city page on this site runs two comparisons, because not every home has gas service. Against electric-resistance heat — baseboard or an electric furnace, both exactly 100% efficient — a heat pump only has to beat COP 1.0, and moving heat instead of generating it clears that bar in almost every climate this site covers, including several cities where the gas comparison says wait.

The reversal, in real numbers

Anchorage, AK costs about $1,630 a year MORE to run against gas, but against resistance heat it saves roughly $3,924 a year, for a 2-year payback — one of the largest swings in the dataset. Fairbanks, AK flips even harder: about $2,077 a year worse against gas becomes about $5,048 a year better against resistance, a 1.6-year payback. Fargo, ND, Bismarck, ND, and Grand Forks, ND — all North Dakota cities where electric baseboard heat is common — show the same reversal at a smaller scale, each moving from a losing gas comparison to a payback under seven years against resistance.

Why the gap is so much bigger here

Gas is priced by the heat it delivers and stays competitive with electricity even at a mediocre heat-pump COP, so a cold-climate seasonal COP as low as 2.3 (see the cold-climate units guide) can still lose to cheap gas. Electric resistance has no such advantage: every unit of heat it delivers costs a full unit of electricity, so even a modest COP of 2.3 means the heat pump uses well under half the electricity for the same warmth. The full arithmetic behind both comparisons is in the methodology guide.