What a heat pump is, in one paragraph
A heat pump is an air conditioner that runs in both directions. In summer it moves heat out of the house; in winter it pulls heat out of the outdoor air, even cold air, and moves it inside, using a compressor rather than a flame. Because it moves heat rather than making it, it delivers two to three units of heat for each unit of electricity in typical conditions, which is the whole economic argument. Ducted versions replace a furnace or air handler and use the existing ducts; ductless mini-splits feed wall-mounted heads; dual-fuel systems keep a furnace or boiler for backup on the coldest hours.
Will it heat a Hamptons house in January?
Yes, if it is a cold-climate model sized properly. Two facts settle it.
First, the temperatures. The design temperatures engineers use for eastern Long Island, the cold point a system must carry, are 15.7°F at Islip and 11.9°F at Westhampton Beach (ASHRAE 2021, via the NYS Clean Heat calculator guide). We have not found a published figure for Montauk; plan on the Westhampton end for the ocean side. Suffolk County is IECC climate zone 4A.
Second, the equipment. The NEEP cold-climate air-source heat pump specification, written for climate zone 4 and colder, lists units that hold capacity and efficiency at 5°F, well below either design temperature. A listed unit sized from a Manual J load calculation, which New York's residential code requires (2020 RCNYS §N1103.7, carried into the 2025 code), carries a South Fork winter with margin. Where the margin runs out on the coldest nights, the backup is either electric resistance strips, which are expensive to run (about $81 per million Btu at Long Island rates, against about $32 for the heat pump), or a dual-fuel arrangement that keeps the existing boiler for those hours.
The failure mode is not the climate. It is the rule-of-thumb contractor who installs a standard heat pump sized "like the old furnace" and lets the resistance strips carry February.
What it costs
National 2026 figures; Hamptons houses are larger and often need two or three systems, so multiply.
| Item | Installed cost |
|---|---|
| Dual-fuel system (heat pump + gas or oil backup) | $7,000–16,500 by one source; $8,000–25,000 by another |
| Cold-climate model premium over a standard heat pump | +$1,000–3,000 |
| Northern-climate installation | 20–30% above base cost |
| Worked example: ducted cold-climate heat pump + panel upgrade + duct sealing, 2,000 sq ft house | $16,000–22,000 before rebates; a Northeast conversion with panel work can pass $20,000 |
| Electrical panel upgrade, 100 A to 200 A | $1,500–4,000 straightforward (most $2,000–3,000); $3,000–6,000 with utility coordination or meter-base work |
| Duct sealing | $1,000–2,500 by one estimate; the Aeroseal process $1,500–6,900 |
| New ductwork | $25–55 per linear foot by scope; $40–65 per linear foot for a whole house by another estimate |
| Ductless alternative | Single zone $2,000–8,000; 2–4 zones $5,000–12,000; +$2,000–7,000 per further zone |
| Oil tank removal, if leaving oil | $400–2,800 above ground; $800–3,400 underground; remediation if contaminated $2,500–15,000+ |
Incentives, as of August 2026
Rebate pages go stale fast. This is the state of play on the date at the top of this guide.
PSEG Long Island, Home Comfort Plus. The NYS Clean Heat program is administered on Long Island by PSEG, so this is one rebate, not a utility rebate plus a state rebate. For a whole-house ducted cold-climate or air-to-water heat pump in a single-family house: $4,000 at market rate; $5,000 for moderate income (under 80% of area median income) or for any household in a designated disadvantaged community; $7,500 for low income (under 60%). Applications must be postmarked by December 31, 2026, and the installer must be a PSEG participating contractor. Ask about this first; a contractor who is not in the program costs you $4,000.
Federal 25C credit: terminated. The 30% Energy Efficient Home Improvement Credit, with its separate $2,000 cap for heat pumps, was ended by the July 4, 2025 tax law (P.L. 119-21) for any property placed in service after December 31, 2025. The IRS FAQ quotes the statute directly. "Placed in service" means operating, not purchased: equipment bought in 2025 and installed in 2026 does not qualify. Any sales material that still shows a federal credit is out of date.
NYSERDA EmPower+. For income-eligible households: up to $14,000 in covered upgrades at or below 60% of area median income and up to $7,000 at 60–80%, with federal HEAR rebate money layered through the same program; the combined benefit can reach $24,000. A standalone federal HOMES rebate does not appear to be live in New York as of this writing.
New York geothermal credit. 25% of installed cost up to $10,000, raised from $5,000 effective July 1, 2025, for a ground-source system on a primary residence. Geothermal is a different and larger project; the credit is why it still pencils for some year-round houses.
Running cost against oil, with Long Island numbers
The national articles say a heat pump heats for less than half the cost of oil. They assume electricity at about 14¢ per kWh. Long Island's residential rate is 27–28¢. Here is the arithmetic with local figures; every input is listed so you can redo it with your own.
- One million Btu of delivered heat is 293 kWh of heat (3,412 Btu per kWh, EIA).
- A heat pump at a seasonal average COP of 2.5 uses 117 kWh of electricity for that million Btu. At 27.5¢, that is about $32. At COP 3.0, about $27. On the coldest days at COP 2.0, about $40. Electric resistance backup, COP 1.0, about $81.
- Heating oil holds 138,500 Btu per gallon (EIA). An oil boiler at 87% efficiency (standard units run 85–90%) delivers about 120,500 Btu per gallon, so a million Btu takes about 8.3 gallons. At $5.42 per gallon, the Long Island average surveyed on July 27, 2026, that is about $45. At the past year's low of $3.67, about $30; at the high of $6.01, about $50.
- The break-even oil price against the COP-2.5 heat pump is roughly $3.90 per gallon.
Oil was above $3.90 for most of the last twelve months, so the heat pump was cheaper to run, by somewhere between nothing and about 30%. It was not cheaper by half, and in the cheapest weeks of January it was not cheaper at all. A seasonal COP of 2.5 is an assumption, and a cold-climate unit that is properly sized and not leaning on its resistance strips can do better; a badly sized one does worse. The heat pump also cools in summer, which the boiler does not, and it removes the tank, the deliveries and the price swings. Whether that is worth $16,000–22,000 less a $4,000 rebate is a house-by-house calculation, and a contractor should show it to you rather than a slogan.
The parts of the house that decide it
Ducts. A heat pump moves more air at a lower temperature than a furnace. Ducts sized for a furnace, or leaking into an attic, produce cold rooms and a system that runs on backup. Duct sealing or new runs belong in the quote, not in the surprises.
Electrical. Many South Fork houses on oil or propane still have 100- or 150-amp service. A 200-amp upgrade is $1,500–4,000 in a straightforward swap and $3,000–6,000 when PSEG has to be involved with the meter base, and it needs a licensed electrician; Suffolk County's Home Improvement Contractor license does not cover electrical work.
Fuel. The Hamptons heat differently from the rest of Suffolk County. County-wide, natural gas is the majority fuel; in the hamlet-level figures we could find for East Hampton and Southampton, heating oil is the single most common fuel. Gas mains reach some streets and not others, and there is no reliable public map, so a contractor's first question is what reaches the house.
The tank. Leaving oil means dealing with the tank: $400–2,800 to remove one above ground, $800–3,400 for a buried one, and $600–3,400 to fill one in place where that is allowed, which it is not everywhere in New York. Contamination, if found, adds $2,500–15,000 or more.
Salt air
For a furnace-and-AC house, the outdoor unit rests all winter. For a heat pump it is the entire heating plant, running through every nor'easter. Trade guidance for coastal work: a salt-spray (ASTM B117) rated condenser coil within about 3–5 miles of the ocean, both coils within a mile, the manufacturer's most stringent option on the oceanfront; the unit raised at least 12 inches above grade, more in flood zones; and a low-pressure rinse 2–4 times a year on oceanfront sites, never a pressure washer. Some manufacturers' coated coils come at no extra cost on the right model. Sources from other coastal markets claim unprotected units can fail in as little as 3–5 years on the beachfront; we have found no Hamptons study, so treat that as a warning, not a measurement.
Second homes
A heat pump makes a closed-up house cheaper to keep warm, which matters because most homeowner policies expect "reasonable care" against freezing, commonly read as keeping the house at or above 55°F or shutting off and draining the water; a 2024 New York case turned on that fact pattern. Pair it with a Wi-Fi temperature alarm (from about $25; some services add $5–10 a month) and a plan for outages: Tropical Storm Isaias in August 2020 knocked out roughly 645,000 PSEG Long Island customers at its peak and took 8 days to fully restore, and a heat pump does not run without power.
The gas law is not about your house
New York's All-Electric Buildings Act restricts fossil-fuel hookups in new buildings of seven stories or less. Its January 1, 2026 start date was suspended in November 2025 pending a federal appeal, and its current status is unsettled. None of it reaches an existing house: renovations, repairs and equipment replacements are not covered. Choosing a heat pump for an existing South Fork house is a decision, not a mandate. A new house is a different conversation to have with the architect.
Ducted, ductless or dual-fuel
- Ducted, all-electric. The existing ducts (sealed) carry a whole-house cold-climate heat pump with resistance backup. Cleanest result, largest electrical and duct work, the rebate's intended case.
- Dual-fuel. The heat pump carries most of the season and the boiler or furnace takes the coldest hours. Cheaper backup than resistance, keeps the tank for now, and it is the common Hamptons compromise for a large house.
- Ductless. One or more mini-splits, $2,000–8,000 a zone, for the houses with no ducts and the wings the central system never reached. Whether a multi-zone ductless design qualifies for the whole-house rebate depends on the program's current rules; ask a participating contractor.
Questions to ask the contractor
- Is the model on the NEEP cold-climate list, and what is its capacity at 5°F?
- Did the sizing come from a Manual J load calculation for this house, and can I see it?
- Are you a PSEG Long Island participating contractor for Home Comfort Plus, and will you file the rebate?
- What refrigerant does the unit use (R-454B or R-32 on equipment built since 2025)?
- What does the panel need, and who does the electrical work?
- What heats the house on the coldest night, and what does that cost to run?
- What is the coil rated for, how high is the unit mounted, and who rinses it?
Sources and method
Compiled 25 August 2026 from the PSEG Long Island Home Comfort Plus rebate page, the IRS FAQ on Public Law 119-21 (25C termination), NYSERDA EmPower+, NY Senate Bill S4882 (geothermal credit), the NEEP cold-climate specification, the NYS Clean Heat calculator user guide (ASHRAE 2021 design temperatures), the 2020 Residential Code of New York State §N1103.7 (Manual J/S), EIA energy conversion factors, the NYSERDA Long Island heating-oil price survey, EnergySage and EIA-derived Long Island electricity rates, ConsumerAffairs, HVAC Base, Filterbuy and HomeGuide 2026 cost guides, the NY Assembly's All-Electric Buildings page with Spectrum News and Canary Media reporting on the November 2025 suspension, LIPA's Isaias 30-day report, and trade guidance on coastal installation (360 Engineering, NuWatt). The running-cost comparison is our own arithmetic from those inputs, with the assumptions stated in the text. Not published on purpose: a Montauk design temperature (none found), 3- to 5-ton cost breakdowns (not cleanly sourced), and a street-by-street gas map (none exists). Reviewed and updated as programs change.