Heat Pump Payback in Nashua, NH
Should Nashua switch to a heat pump?
Nashua is a place where a heat pump genuinely costs more to operate than the alternative. Swap a failed furnace and AC for a heat pump rather than buying like-for-like, and the extra cost here runs $5,500. Unfortunately the electric bill outweighs the gas bill it replaces by about $189 a year here, so the extra spend stays unrecovered. That's Nashua's own climate and rates talking, not a hedge or a caveat.
Compare against another city
This runs the same numbers for 3206 US cities, not just Nashua. Look one up here.
Nashua's weather, in the numbers that matter
5681 heating degree days pile up here every year, so Nashua has a cold winter that leans hard on heating equipment; the cooling side runs to 775 cooling degree days, where summers add a moderate cooling load. 3.9°F is the figure equipment gets sized against here, the 99th-percentile cold snap, not an average day, with a low of -0.9°F in the 2024 station record. Worked through the model, that's a seasonal COP of 2.79 on the cold-climate unit fit for this climate. A cold-climate unit is the right call in Nashua, below 25°F design temperature, a standard heat pump leans hard on electric-resistance backup, which erases most of the savings. Source: NOAA station Boire Field Airport, 2.7 miles from Nashua, the closest one on record.
Nashua's running-cost comparison, in dollars
Electricity use for heating alone comes out to about 5,156 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $1,559 a year. Nashua's gas rate of $18.61 per Mcf, applied to the 59 Mcf a year the furnace burns, puts the current furnace-and-AC running cost near $1,370 a year, against 26.80¢ per kWh for electricity. Because the heat pump costs more to run here, the gap only widens with time: $8,329 behind after 15 years compared with replacing the furnace and AC like-for-like.
What would change Nashua's answer
For the verdict in Nashua to flip, electricity would need to drop to about 22.9¢/kWh from 26.80¢, or gas climb past $21.80 per Mcf from $18.61. A utility offering a lower heat pump rate can change this. Until then, no quote price makes a heat pump pay back against gas in Nashua; the case for one here rests on comfort, cooling, or replacing electric heat instead.
If your home heats with electric baseboard instead of gas
Not every home in Nashua has gas service. Swap the comparison to resistance heat instead of gas, and Nashua's answer improves. About $2,565 a year comes back this way, enough that the 3.9-year payback clears the $10,000 premium comfortably within the equipment's life.
Where Nashua ranks in this dataset
Ranked against the other 3206 cities covered, Nashua comes in at 325 for heating severity, 1 would be the coldest place in the dataset, and 381 by population, where 1 is largest. That's the coldest third of the dataset, where climate does most of the work behind this figure.
Next step if you live in Nashua
Nashua, New Hampshire is home to about 91,851 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. In Nashua, nothing is lost by holding off until the current equipment genuinely fails.
Get quotes from local HVAC contractors before deciding.
More on how this number was built
Nothing above is a black box: the methodology guide shows the full arithmetic behind Nashua's 2.79 seasonal COP and payback figure. At a 3.9°F design temperature, Nashua sits in cold-climate territory; the guide to that class of unit explains why.