Should Sun Prairie switch to a heat pump?
Here in Sun Prairie, the honest answer is that a heat pump raises your annual running cost. Against a like-for-like gas furnace and AC swap, going electric costs $3,500 more up front here (already netting out a $2,000 tax credit). The heat pump would cost about $403 more a year to run than the furnace it replaces — a premium with no payback. There's no spin on that: Sun Prairie's numbers say wait.
The climate behind Sun Prairie's payback figure
Degree days tell the story here: Sun Prairie racks up 5775 heating degree days each year (base 65°F), and summers add a moderate cooling load, with 761 cooling degree days on the cooling side. Sizing runs off the design temperature, not the average day: -9°F here (record low -11°F), which works out to a seasonal COP of 2.48 for the cold-climate class of unit this climate calls for. A cold-climate unit is the right call in Sun Prairie — below 25°F design temperature, a standard heat pump leans hard on electric-resistance backup, which erases most of the savings. Source: NOAA station DANE CO REGIONAL-TRUAX FIELD, 6.1 miles from Sun Prairie — the closest one on record.
Sun Prairie's running-cost comparison, in dollars
Electricity use for heating alone comes out to about 5,896 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $1,235 a year. That compares with roughly 60 Mcf a year of gas at Sun Prairie's 10.74 per-Mcf rate — about $832 a year — against a local electricity rate of 18.87¢/kWh. Looked at as a full purchase rather than an incremental one, payback here is longer than the 15-year equipment life, leaving the 15-year total $9,545 behind.
The other scenario: no gas furnace to begin with
Gas isn't universal in Sun Prairie — many houses run on electric heat already. Compared with baseboard or electric-furnace resistance heat, the numbers shift in the heat pump’s favor. About $1,710 a year comes back this way, enough that the 4.7-year payback clears the $8,000 premium comfortably within the equipment's life.
How Sun Prairie compares nationally
Ranked against the other 3206 cities covered, Sun Prairie comes in at 285 for heating severity — 1 would be the coldest place in the dataset — and 1053 by population, where 1 is largest. That's the coldest third of the dataset, where climate does most of the work behind this figure.
What to do with this number in Sun Prairie
About 39,253 people live in Sun Prairie, Wisconsin, and every number on this page is what a contractor would actually work from when quoting a system here — the point isn't to replace that quote, it's to tell you whether to bother asking for one. Here, there's no cost penalty to waiting until your current furnace or AC actually needs replacing.
Get quotes from local HVAC contractors before deciding.
More on how this number was built
Every constant behind this page — the 2.48 seasonal COP, the degree-day corrections, the equipment costs — is documented in the methodology guide. Sun Prairie's -9°F design temperature falls on the cold side of the 25°F cutoff the cold-climate unit guide walks through.