Largo, FL: the heat pump payback math
In Largo, a heat pump pays for itself within a reasonable window. $1,000 is what Largo 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. That premium is recovered through $326 of lower running costs every year, landing the payback clock at roughly 3.1 years. That's a real payback, built from Largo's own climate and utility rates, not a national guess.
The climate behind Largo's payback figure
364 heating degree days pile up here every year, so Largo barely has a winter to speak of; the cooling side runs to 3958 cooling degree days, where summers are severe enough that cooling can dominate the annual bill. The 99% winter design temperature here — the cold snap equipment must be sized for, not the seasonal average — is 43°F, against a record low of 37.9°F. That puts the seasonal coefficient of performance at 3.48 for the recommended standard unit. A standard ducted system is enough here; Largo's design temperature doesn't justify the cold-climate premium. These numbers come from ST PETE-CLWTR INTL AIRPORT, the closest NOAA station, 5.3 miles out.
Largo's running-cost comparison, in dollars
Modelled on a typical 2000-square-foot house, the heat pump draws about 265 kWh a year to keep it warm, plus cooling, for a combined electric bill near $562 a year. The gas furnace it replaces burns roughly 4 Mcf a year at 25.48 per Mcf here, for a running cost near $888 a year (electricity here runs 15.43¢/kWh). Priced as a standalone purchase rather than against a like-for-like replacement, equipment payback runs about 33.7 years, for a 15-year net position $3,897 ahead.
The other scenario: no gas furnace to begin with
Not every home in Largo has gas service. Swap the comparison to resistance heat instead of gas, and Largo's answer improves. About $372 a year comes back this way, enough that the 14.8-year payback clears the $5,500 premium comfortably within the equipment's life.
How Largo compares nationally
Ranked against the other 3206 cities covered, Largo comes in at 3099 for heating severity — 1 would be the coldest place in the dataset — and 450 by population, where 1 is largest. That's the mildest third of cities covered, where utility rates carry more of the answer than climate does.
Next step for 82,337 people in Largo
About 82,337 people live in Largo, Florida, 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, it's worth getting quotes before your current system fails, not after.
Line up a few local HVAC quotes before you decide.
More on how this number was built
Nothing above is a black box: the methodology guide shows the full arithmetic behind Largo's 3.48 seasonal COP and payback figure. See what Largo's figure looks like without the $2,000 federal credit in the guide to how that credit moves the payback window.