HVAC System Replacement Cost in Dover, New Hampshire
Expect to pay $11,300 to $24,500 for full HVAC system replacement in Dover, NH. Most homeowners end up near $18,600, depending on the equipment tier and how much of the old setup can be reused.
Dover Weather and HVAC Load
In a normal year, Dover racks up 6,919 heating and 410 cooling degree days (NOAA 1991-2020 normals). Heating is the bigger job here, and furnaces and heat pumps in Dover put in far more hours than the air conditioner. On average, Dover gets 150 freezing nights and 6 days above 90°F per year. Snowfall averages about 39 inches. For a 2,000 sq ft house, this climate points to a heating load somewhere near 70,000 BTU/h. Treat that as a starting number. A Manual J calculation will move it up or down based on insulation and windows.
| Heating degree days / year | 6,919 |
|---|---|
| Cooling degree days / year | 410 |
| Nights at or below 32°F | 150 |
| Days above 90°F | 6 |
| Average low / high | 37°F / 57.1°F |
Dover Housing Stock
Census figures put the median build year in Dover at 1975, so a typical house here has about 51 years on it. A lot of these homes are on their second or third system by now. The ductwork is usually original, and leaky joints are common. Dover has roughly 7,700 owner-occupied homes, or 51.3% of households. With a median household income of $92,748 and a median home value of $398,500, local labor rates come out above the national middle in our model.
NOAA storm reports for Strafford County show 2 hail days and 14 days with damaging thunderstorm winds over the six years from 2020 to 2025. The largest hail reported was 1.75 inches across. Storms here are more likely to cause power surges than coil damage, so a surge protector on the outdoor unit is worth the small cost.
When Replacement Makes Sense
- Both units keep needing repairs
- An old R-22 AC paired with an aging furnace
- Some rooms are uncomfortable, and the energy bills are high
What Moves the Price
- Furnace plus AC, or heat pump plus air handler
- Thermostat and zoning upgrades
- Duct repair or replacement
- Permits and electrical work
- Equipment sized to the house and climate
- Efficiency ratings: SEER2, AFUE and HSPF2
We raised the national figures about 33% for Dover using local income, home values and the equipment size this climate needs. Real bids can still come in outside the range, so collect three written quotes.
What the Quote Should Cover
- Startup, testing and warranty registration
- Removing the old equipment
- New, matched heating and cooling equipment
- A load calculation and system design
- Duct connections and sealing
New Hampshire Permits, Efficiency Rules and Rebates
New Hampshire falls in the DOE's North region. New split central air conditioners must meet at least 13.4 SEER2, and heat pumps sold anywhere in the U.S. need 14.3 SEER2 and 7.5 HSPF2. Equipment replacements in Dover generally need a mechanical permit, and a reputable contractor will pull it for you. Ask for their New Hampshire license or registration number and a certificate of insurance with the quote. The federal 25C tax credit ended for equipment installed after December 31, 2025, so incentives now come mostly from utilities and state programs. Check your electric and gas utility's rebate page before you pick equipment.
Before You Hire
- Ask for a duct leakage test. Leaky ducts can lose 20 to 30% of what the system puts out.
- Replacing both pieces at once usually costs less than two separate jobs a few years apart.
- Get one quote for a heat pump system and one for a furnace plus AC.
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HVAC System Replacement Questions from Dover Homeowners
How much is full HVAC system replacement in Dover?
Plan on $11,300 to $24,500, with most jobs near $18,600. Equipment efficiency, house size and the condition of the ducts and wiring decide where your quote falls.
When is the best time to schedule full HVAC system replacement in Dover?
Between late spring and early fall. Dover averages 150 freezing nights a year, and heating calls spike from November through February.
Can I replace only the AC and keep my furnace?
Yes, as long as the indoor coil and blower work with the new AC. A mismatched system loses efficiency and can void the warranty.
How often should an HVAC system be replaced?
Most systems get replaced every 15 to 20 years. AC units and heat pumps usually wear out before gas furnaces do.
HVAC System Replacement Near Dover
- Rochester $10,100 to $21,900
- Concord $10,600 to $23,100
- Nashua $11,000 to $23,900
- Manchester $10,400 to $22,700
Sources: U.S. Census Bureau ACS 5-year estimates 2019-2023 and 2024 population estimates; NOAA NCEI U.S. Climate Normals 1991-2020, station Durham; NOAA Storm Events Database 2020-2025, Strafford County. Prices are our estimates, not contractor quotes. Updated 2026.