Farmington, MI: the heat pump payback math
Farmington is a place where a heat pump genuinely costs more to operate than the alternative. $3,500 is what Farmington would pay extra to go electric rather than replace the furnace and AC with the same again, once the $2,000 federal credit is applied. The heat pump would cost about $265 more a year to run than the furnace it replaces — a premium with no payback. There's no spin on that: Farmington's numbers say wait.
Why Farmington's climate drives this number
Degree days tell the story here: Farmington racks up 4971 heating degree days each year (base 65°F), and summers add a moderate cooling load, with 954 cooling degree days on the cooling side. The 99% winter design temperature here — the cold snap equipment must be sized for, not the seasonal average — is 5.9°F, against a record low of -2.4°F. That puts the seasonal coefficient of performance at 2.84 for the recommended cold-climate unit. Farmington needs the cold-climate class of unit: past a 25°F design temperature a standard heat pump falls back on resistance backup often enough to eat the savings. Climate figures trace to the nearest NOAA station, OAKLAND/TROY AIRPORT, 11.7 miles from Farmington.
The month-to-month numbers for Farmington
Electricity use for heating alone comes out to about 4,432 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $1,087 a year. Farmington's gas rate of 10.92 per Mcf, applied to the 52 Mcf a year the furnace burns, puts its running cost near $822 a year, against 20.72¢ per kWh for electricity. Priced as a standalone purchase rather than against a like-for-like replacement, equipment payback runs past the 15-year equipment life, for a 15-year net position $7,480 behind.
If your home heats with electric baseboard instead of gas
Not every home in Farmington has gas service. Swap the comparison to resistance heat instead of gas, and Farmington's answer improves. The saving here runs about $1,777 a year, which recovers the extra $8,000 spent going electric in roughly 4.5 years.
Where Farmington ranks in this dataset
Farmington lands at position 783 out of 3206 cities on heating severity (coldest is 1), and 2887 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 Farmington
About 11,547 people live in Farmington, Michigan, 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.
Line up a few local HVAC quotes before you decide.
Where Farmington's figure comes from
Nothing above is a black box: the methodology guide shows the full arithmetic behind Farmington's 2.84 seasonal COP and payback figure. Farmington's 5.9°F design temperature falls on the cold side of the 25°F cutoff the cold-climate unit guide walks through.