Heat pump vs. gas furnace in Gaithersburg, MD
Gaithersburg technically pencils out, but only past the point the equipment would need replacing anyway. Against a like-for-like gas furnace and AC swap, going electric costs $3,500 more up front here (already netting out a $2,000 tax credit). Lower bills claw that back: about $119 saved annually, for a payback of roughly 29.5 years. That's a technicality, not a recommendation, for anyone actually living in Gaithersburg.
How cold Gaithersburg actually gets
Degree days tell the story here: Gaithersburg racks up 3720 heating degree days each year (base 65°F), and summers are hot enough that cooling matters as much as heating, with 1541 cooling degree days on the cooling side. Sizing runs off the design temperature, not the average day: 14.9°F here (record low 12.9°F), which works out to a seasonal COP of 3.06 for the cold-climate class of unit this climate calls for. Gaithersburg needs the cold-climate class of unit: past a 25°F design temperature a standard heat pump falls back on resistance backup often enough to eat the savings. These numbers come from COLLEGE PARK AP, the closest NOAA station, 18.7 miles out.
What it actually costs to run, year to year
Modelled on a typical 2000-square-foot house, the heat pump draws about 3,078 kWh a year to keep it warm, plus cooling, for a combined electric bill near $929 a year. The gas furnace it replaces burns roughly 39 Mcf a year at 16.14 per Mcf here, for a running cost near $1,048 a year (electricity here runs 21.16¢/kWh). Priced as a standalone purchase rather than against a like-for-like replacement, equipment payback runs about 113.9 years, for a 15-year net position $1,722 behind.
Electric resistance heat in Gaithersburg, compared
Gas isn't universal in Gaithersburg — many houses run on electric heat already. Against electric-resistance heat — baseboard or an electric furnace, both 100% efficient but still just resistance — the case for switching gets stronger here. The saving here runs about $1,486 a year, which recovers the extra $8,000 spent going electric in roughly 5.4 years.
How Gaithersburg compares nationally
Among 3206 cities, Gaithersburg's winter puts it at rank 1659 for severity, while its size puts it at rank 549 for population — 1 in both cases being the extreme. That's the middle third for winter severity among the cities covered here.
What to do with this number in Gaithersburg
Gaithersburg, Maryland is home to about 70,686 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 Gaithersburg, nothing is lost by holding off until the current equipment genuinely fails.
Line up a few local HVAC quotes before you decide.
Where Gaithersburg's figure comes from
Nothing above is a black box: the methodology guide shows the full arithmetic behind Gaithersburg's 3.06 seasonal COP and payback figure. Gaithersburg's 14.9°F design temperature falls on the cold side of the 25°F cutoff the cold-climate unit guide walks through.