Donna, TX: the heat pump payback math
Donna is a clear case: a heat pump beats what you have by a wide margin. Swap a failed furnace and AC for a heat pump rather than buying like-for-like, and the extra cost here runs $1,000 after a $2,000 federal tax credit. Donna's residents would see roughly $357 a year back in running costs, putting the payback around 2.8 years. That verdict holds specifically for Donna's own climate and rates, not a national average.
Donna's weather, in the numbers that matter
Degree days tell the story here: Donna racks up 327 heating degree days each year (base 65°F), and summers are severe enough that cooling can dominate the annual bill, with 4622 cooling degree days on the cooling side. 39.2°F is the figure equipment gets sized against here — the 99th-percentile cold snap, not an average day — with a record low of 24.6°F on file. Worked through the model, that's a seasonal COP of 3.37 on the standard unit fit for this climate. Donna's winters don't get cold enough to need the cold-climate premium — a standard unit holds up fine. Source: NOAA station MID VALLEY AIRPORT, 4.3 miles from Donna — the closest one on record.
What it actually costs to run, year to year
Electricity use for heating alone comes out to about 246 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $676 a year. The gas furnace it replaces burns roughly 3 Mcf a year at 19.42 per Mcf here, for a running cost near $1,034 a year (electricity here runs 16.15¢/kWh). Buy it outright, not incrementally, and payback stretches to 30.8 years; over 15 years the net position sits $4,361 ahead.
Electric resistance heat in Donna, compared
Plenty of homes in Donna heat with electricity alone, no gas line involved. Compared with baseboard or electric-furnace resistance heat, the numbers shift in the heat pump’s favor. Switching saves about $425 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 12.9 years.
Donna against the rest of the country
Donna lands at position 3111 out of 3206 cities on heating severity (coldest is 1), and 2206 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 Donna, TX
Donna, Texas is home to about 16,876 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, Donna is a place worth lining up quotes ahead of a breakdown, not waiting for one.
Ask a local HVAC contractor for a quote before committing either way.
More on how this number was built
The methodology guide walks through exactly how Donna's 3.37 seasonal COP and the rest of this page's numbers get built. The $2,000 federal credit baked into Donna's number is explained, with the before-and-after math, in the tax credit guide.