Should Carlisle switch to a heat pump?

The payback math works in Carlisle on paper, past the equipment's own working life. $3,500 is what Carlisle 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. Lower bills claw that back: about $63 saved annually, for a payback of roughly 55.5 years. That's a technicality, not a recommendation, for anyone actually living in Carlisle.

How cold Carlisle actually gets

Carlisle has a real but manageable winter — 4003 heating degree days a year against a 65°F base — and summers are hot enough that cooling matters as much as heating, at 1516 cooling degree days. The 99% winter design temperature here — the cold snap equipment must be sized for, not the seasonal average — is 12°F, against a record low of 10.9°F. That puts the seasonal coefficient of performance at 2.99 for the recommended cold-climate unit. Below the 25°F line where a standard machine starts leaning on resistance backup, Carlisle sits firmly in cold-climate territory, so that's the class of unit priced here. These numbers come from CAPITAL CITY AIRPORT, the closest NOAA station, 18.7 miles out.

What it actually costs to run, year to year

Electricity use for heating alone comes out to about 3,390 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $972 a year. Carlisle's gas rate of 15.04 per Mcf, applied to the 42 Mcf a year the furnace burns, puts its running cost near $1,035 a year, against 20.75¢ per kWh for electricity. Priced as a standalone purchase rather than against a like-for-like replacement, equipment payback runs about 214.1 years, for a 15-year net position $2,554 behind.

Electric resistance heat in Carlisle, compared

Not every home in Carlisle has gas service. Swap the comparison to resistance heat instead of gas, and Carlisle's answer improves. The saving here runs about $1,539 a year, which recovers the extra $8,000 spent going electric in roughly 5.2 years.

How Carlisle compares nationally

Ranked against the other 3206 cities covered, Carlisle comes in at 1502 for heating severity — 1 would be the coldest place in the dataset — and 1751 by population, where 1 is largest. That's the middle third for winter severity among the cities covered here.

What to do with this number in Carlisle

Carlisle, Pennsylvania is home to about 22,517 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 Carlisle, nothing is lost by holding off until the current equipment genuinely fails.

Ask a local HVAC contractor for a quote before committing either way.

More on how this number was built

Every constant behind this page — the 2.99 seasonal COP, the degree-day corrections, the equipment costs — is documented in the methodology guide. Carlisle's 12°F design temperature falls on the cold side of the 25°F cutoff the cold-climate unit guide walks through.