Gretna, LA: the heat pump payback math
In Gretna, a heat pump pays for itself within a reasonable window. Against a like-for-like gas furnace and AC swap, going electric costs $1,000 more up front here (already netting out a $2,000 tax credit). Lower bills claw that back: about $273 saved annually, for a payback of roughly 3.7 years. The window here is reasonable, and it's specific to what Gretna actually pays for power and gas.
How cold Gretna actually gets
964 heating degree days pile up here every year, so Gretna barely has a winter to speak of; the cooling side runs to 3433 cooling degree days, where summers are severe enough that cooling can dominate the annual bill. Sizing runs off the design temperature, not the average day: 30°F here (record low 21°F), which works out to a seasonal COP of 3.09 for the standard class of unit this climate calls for. Gretna's winters don't get cold enough to need the cold-climate premium — a standard unit holds up fine. Source: NOAA station NEW ORLEANS NAS, 6.8 miles from Gretna — the closest one on record.
Gretna's running-cost comparison, in dollars
A 2000-square-foot house here would pull roughly 790 heating kilowatt-hours annually on top of cooling, totalling about $503 a year on electricity. The gas furnace it replaces burns roughly 10 Mcf a year at 17.38 per Mcf here, for a running cost near $776 a year (electricity here runs 13.52¢/kWh). Looked at as a full purchase rather than an incremental one, payback here is roughly 40.2 years, leaving the 15-year total $3,102 ahead.
If your home heats with electric baseboard instead of gas
Not every home in Gretna has gas service. Compared with baseboard or electric-furnace resistance heat, the numbers shift in the heat pump’s favor. Switching saves about $429 a year here — a heat pump moving heat rather than generating it needs far less electricity than resistance coils — so the extra $5,500 spent up front comes back in about 12.8 years.
How Gretna compares nationally
Gretna lands at position 2917 out of 3206 cities on heating severity (coldest is 1), and 2177 out of 3206 by population size (biggest is 1). That's the mildest third of cities covered, where utility rates carry more of the answer than climate does.
Deciding what's next in Gretna, LA
Gretna, Louisiana is home to about 17,185 people, and the figures above are the same ones a local HVAC contractor uses to size and quote a system — this site doesn't guess where a real quote would land, it just tells you whether it's worth asking for one. Given the math above, Gretna is a place worth lining up quotes ahead of a breakdown, not waiting for one.
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 Gretna's 3.09 seasonal COP and payback figure. The $2,000 federal credit baked into Gretna's number is explained, with the before-and-after math, in the tax credit guide.