Summit, NJ: the heat pump payback math
Here in Summit, the honest answer is that a heat pump raises your annual running cost. Swap a failed furnace and AC for a heat pump rather than buying like-for-like, and the extra cost here runs $3,500 after a $2,000 federal tax credit. Unfortunately the electric bill outweighs the gas bill it replaces by about $139 a year here, so the extra spend stays unrecovered. There's no spin on that: Summit's numbers say wait.
Why Summit's climate drives this number
4806 heating degree days pile up here every year, so Summit has a real but manageable winter; the cooling side runs to 942 cooling degree days, where summers add a moderate cooling load. Sizing runs off the design temperature, not the average day: 12.2°F here (record low 6.8°F), which works out to a seasonal COP of 2.99 for the cold-climate class of unit this climate calls for. Below the 25°F line where a standard machine starts leaning on resistance backup, Summit sits firmly in cold-climate territory, so that's the class of unit priced here. These numbers come from MORRISTOWN MUNICIPAL AIRPORT, the closest NOAA station, 6.4 miles out.
The month-to-month numbers for Summit
A 2000-square-foot house here would pull roughly 4,070 heating kilowatt-hours annually on top of cooling, totalling about $1,134 a year on electricity. Summit's gas rate of 14.21 per Mcf, applied to the 50 Mcf a year the furnace burns, puts its running cost near $995 a year, against 23.28¢ per kWh for electricity. 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 $5,585 behind.
If your home heats with electric baseboard instead of gas
Plenty of homes in Summit heat with electricity alone, no gas line involved. Against electric-resistance heat — baseboard or an electric furnace, both 100% efficient but still just resistance — the case for switching gets stronger here. About $1,983 a year comes back this way, enough that the 4-year payback clears the $8,000 premium comfortably within the equipment's life.
Where Summit ranks in this dataset
Summit lands at position 941 out of 3206 cities on heating severity (coldest is 1), and 1706 out of 3206 by population size (biggest is 1). 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 Summit
About 23,102 people live in Summit, New Jersey, 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.
Ask a local HVAC contractor for a quote before committing either way.
Where Summit's figure comes from
Nothing above is a black box: the methodology guide shows the full arithmetic behind Summit's 2.99 seasonal COP and payback figure. Summit's 12.2°F design temperature falls on the cold side of the 25°F cutoff the cold-climate unit guide walks through.