Is a heat pump worth it in Grimes?
Here in Grimes, 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 $66 more a year to run than the furnace it replaces — a premium with no payback. There's no spin on that: Grimes's numbers say wait.
The climate behind Grimes's payback figure
Grimes has a cold winter that leans hard on heating equipment — 5300 heating degree days a year against a 65°F base — and summers add a moderate cooling load, at 961 cooling degree days. -7.6°F is the figure equipment gets sized against here — the 99th-percentile cold snap, not an average day — with a record low of -16.6°F on file. Worked through the model, that's a seasonal COP of 2.52 on the cold-climate unit fit for this climate. A cold-climate unit is the right call in Grimes — below 25°F design temperature, a standard heat pump leans hard on electric-resistance backup, which erases most of the savings. Source: NOAA station ANKENY REGIONAL AIRPORT, 12.2 miles from Grimes — the closest one on record.
What it actually costs to run, year to year
A 2000-square-foot house here would pull roughly 5,326 heating kilowatt-hours annually on top of cooling, totalling about $818 a year on electricity. That compares with roughly 55 Mcf a year of gas at Grimes's 10.61 per-Mcf rate — about $751 a year — against a local electricity rate of 13.31¢/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 $4,497 behind.
The other scenario: no gas furnace to begin with
Not every home in Grimes has gas service. Swap the comparison to resistance heat instead of gas, and Grimes's answer improves. The saving here runs about $1,134 a year, which recovers the extra $8,000 spent going electric in roughly 7.1 years.
Where Grimes ranks in this dataset
Among 3206 cities, Grimes's winter puts it at rank 486 for severity, while its size puts it at rank 2169 for population — 1 in both cases being the extreme. That's the coldest third of the dataset, where climate does most of the work behind this figure.
Deciding what's next in Grimes, IA
About 17,266 people live in Grimes, Iowa, 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
The methodology guide walks through exactly how Grimes's 2.52 seasonal COP and the rest of this page's numbers get built. Grimes's -7.6°F design temperature falls on the cold side of the 25°F cutoff the cold-climate unit guide walks through.