Port Washington grew up behind the railroad. The Long Island Rail Road’s extension opened on June 23, 1898, rapid development followed, and 34.7% of the hamlet’s 6,312 housing units, 2,190 homes, were standing before 1940. The 1950s added another 28.3%, and the median home dates from 1952. Just 63.5% of homes heat with utility gas; 21.8% burn fuel oil, 9.7% use electricity and 3.6% bottled gas.
Port Washington is an unincorporated hamlet in the Town of North Hempstead on the Cow Neck Peninsula, with Manhasset Bay to the west and Hempstead Harbor to the east. It is not the whole peninsula. A 1912 vote to make Port Washington a village failed by nine votes; Sands Point incorporated on its own, and Baxter Estates, Flower Hill and Manorhaven incorporated to keep home rule, ending a 1930 plan for a City of Greater Port Washington. Port Washington North is a separate village too. The figures here describe the hamlet alone.
70.5% of its units are detached houses, 6.9% are in two-unit buildings and 3.6% are single-family attached homes, and 77.8% of occupied homes are owner-occupied. The apartment buildings, 9.7% of units in buildings of fifty or more and 3.1% in buildings of twenty to forty-nine, are run as whole buildings, so the roof and the exterior walls belong to the owner or the board, and that decision is theirs.
The houses we insulate in Port Washington
From the 1870s Port Washington was a sand-mining town, with the largest sandbank east of the Mississippi River and easy barge access to Manhattan. Main Street took its name in 1912, replacing Flower Hill Avenue. The 2,190 pre-1940 houses come out of those decades: frame houses with plaster on wood lath over empty stud bays, often balloon-framed so the bays run from cellar to attic, with attics that are floored, finished or reachable only through a closet hatch. Knob-and-tube wiring is possible at this age, and we confirm nothing live is buried before a cavity is filled.
The ground adds a wrinkle. Port Washington sits on the Harbor Hill Moraine, rising from sea level at the harbors to about 270 feet at Beacon Hill, and a house built into one of its slopes can have a lower level below grade on one side and open on the other. That level has a rim joist exposed at full height and a foundation wall that loses heat to open air, and it deserves the same attention as an outside wall.
The 1940s and 50s, 652 and 1,785 units, brought capes, ranches and small colonials. The cape’s weak line runs around its upstairs: knee walls with no air barrier behind them, joist bays open to the eaves and shallow sloped ceilings. The ranch’s is one wide attic floor, thin at the eaves and open around every ceiling box and flue. The 5.2% from the 1960s and 3.2% from the 1970s add split-levels with rooms over garages.
Newer building counts here too: 11.1% since 2000, 433 units in the 2000s and 268 in the 2010s, plus 7.1% from the 1980s and 90s. Those houses and townhouses have insulated walls. Their losses are ductwork and air handlers in vented attics, vaulted ceilings without baffles, rooms over garages and, in attached homes, party walls left open to a shared attic.
Where the gas main stops: oil, propane and electric heat in Port Washington
National Grid gas runs on many Port Washington streets, but not all of them, and many homes heat with something else. Each fuel changes what sealing and insulating are worth and what we check before tightening a house.
Electric heat, 9.7% of homes, puts every unit of lost heat on the PSEG Long Island bill. Electric baseboard turns one unit of electricity into one unit of heat, so the main way to shrink that bill without new equipment is to lose less heat, and sealing and insulating does that directly. A house planning a heat pump should be sealed and insulated first or at the same time, so the equipment is sized to the tightened house; a heat pump sized for a leaky one costs more to buy and runs less efficiently in short cycles.
Oil, 21.8%, and bottled gas, 3.6%, are delivered fuels, so the savings show up as fewer deliveries or tank fills. Both usually mean a burner in the basement, and many of those vent up a chimney that depends on the house supplying air. We note how every appliance vents before sealing, check the draft afterward, and close the chimney gap in the attic with sheet metal and high-temperature sealant, never foam. The fill and vent pipes through the foundation get sealed with the rim.
Switching fuels is the right moment to insulate. When an owner trades oil or propane for gas, or for a heat pump, the heating contractor’s load calculation should be run on the house as it will be after the attic, rim and walls are done, not as it was.
We seal before we insulate
Insulation slows heat through a surface. Air leaks carry heat around it, and on a peninsula with water on both sides, wind finds every gap on the exposed side of a house. Sealing is what keeps insulation working on a windy day.
In a Port Washington cape the order is: block the joist bays under the knee walls at the eave line, put an air barrier on the attic side of each knee wall, seal the top plates, the plumbing and flue chases and the bath fan, and baffle the slopes so they can be filled without closing off the eaves. Then insulate the knee walls, slopes and flat attic, and finish in the basement with closed cell foam on the rim joist.
If a quote specifies a depth of insulation and never mentions air sealing, it is half a job.
What insulation costs in Port Washington
Most of our projects run between $3,500 and $12,500. A 1950s ranch with an open attic and a basement rim sits at the lower end, and a cape moves up with its knee walls and slopes. A pre-1940 house is priced on its attic access and whether the walls get filled, and a house on a slope adds its exposed lower-level rim and wall. In a newer house or townhouse the work is priced on attic ducts, vaulted ceilings and party walls rather than walls. The fuel does not change our price; it changes how the savings arrive.
Open cell foam runs R-3.9 to R-4.2 per inch. Closed cell runs R-6.9 to R-7.1 per inch and also acts as a vapor retarder, which is why it costs more and why it is right in some assemblies and unnecessary in others. All products are manufactured in the United States and meet applicable building code and safety standards. ENERGY STAR says sealing air leaks and adding insulation can save up to 10% on annual energy bills.
Insulation rebates in Port Washington
Port Washington’s electric company is PSEG Long Island, and its gas company, where a street has gas, is National Grid. NYSERDA’s Comfort Home program does not serve PSEG Long Island homes, so the rebate route here is PSEG Long Island’s, with EmPower+ for income-eligible households.
It begins with PSEG Long Island’s free Whole House Energy Assessment: an insulation and draft check, a thermal scan and a blower door test. PSEG Long Island then lists a $2,500 insulation rebate and a $1,000 air-sealing rebate for market-rate single-family homes, with higher amounts for income-qualified homes and homes in state-designated disadvantaged communities, paid through its participating contractors. Its rules name oil, natural gas, propane and electric as eligible heating fuels, so a Port Washington house off the gas main is not shut out. Insulation must be paired with blower-door-assisted air sealing. The list is written for single-family homes, so townhouse owners should confirm with PSEG Long Island.
NYSERDA’s EmPower+ pays for air sealing and insulation for income-eligible owners and renters: no cost up to $14,000 in the lower-income tier (at or below $98,925 for a Nassau household of four), or half the cost up to $7,000 in the moderate tier (below $131,900 for four). Long Island households should check eligibility on the MyEnergy portal. National Grid’s Long Island insulation rebates are closed to new applications, but its gas customers who meet the EmPower+ income guidelines can get no-cost home safety repairs through its Weatherization Health and Safety Program after applying to EmPower+.
Every one of these programs pays through its own participating contractors, so check with the program before you sign anything. The federal insulation tax credit, Section 25C, ended for work placed in service after 31 December 2025, and a 2026 job gets no federal credit. New York has no state tax credit for insulation. See our New York and New Jersey rebate guide for the full picture.
Code and climate in Port Washington
81.7% of Port Washington’s housing was built before 1980. New York’s first statewide energy code took effect on 1 January 1979, decades after the hamlet’s pre-1940 and 1950s houses went up. Nassau County is Climate Zone 4.
The 2025 Energy Conservation Construction Code of New York State has been in force since 31 December 2025. For new homes it requires R-49 ceilings, or R-38 over the full ceiling where it runs uncompressed over the wall top plates at the eaves; R-30 floors; basement and crawl space walls at R-15 continuous, R-19, or R-13 plus R-5 continuous, which is the standard a walk-out lower level is measured against; U-0.27 windows; and air leakage of no more than 3.0 air changes per hour at 50 pascals.
Existing houses are not dragged up to that table. Parts that are not altered need not comply, and New York’s code requires no blower door test when an existing home is insulated. When an alteration exposes wall or roof-ceiling cavities, they are to be insulated to full depth. ENERGY STAR recommends R-60 for an uninsulated attic in this zone and R-49 where 3 to 4 inches are already there.
Common questions about insulation in Port Washington
Do you install insulation in Port Washington, NY?
Yes. Much of our Port Washington work is in the 34.7% built before 1940, with empty plaster walls and hard-to-reach attics, and in the 1940s and 50s capes and ranches. We also work on houses stepping down the hills, where the lower level loses heat like an outside wall, on newer houses and townhouses with attic ducts, and on homes heated by oil, propane or electricity.
How much does insulation cost in Port Washington?
Most projects run $3,500 to $12,500. A 1950s ranch with an open attic and a basement rim is at the lower end; a cape adds knee walls and slopes. A pre-1940 house moves up with difficult attic access or wall filling, and a house on a slope adds its exposed lower level. Newer houses are priced on ducts, vaulted ceilings and party walls. The heating fuel does not change the price, only where the savings show. A free walk-through ends with a written scope and price.
Are there insulation rebates in Port Washington?
Yes. Port Washington is PSEG Long Island territory, and PSEG Long Island lists a $2,500 insulation rebate and a $1,000 air-sealing rebate for market-rate single-family homes, with more for income-qualified homes, through its participating contractors after a free Whole House Energy Assessment. Homes heated with oil, propane or electricity are eligible. Comfort Home does not serve PSEG Long Island customers. Income-eligible owners and renters can check EmPower+ on the MyEnergy portal. There is no federal 25C credit for 2026 work and no New York state insulation credit.
Our house is in Manorhaven, not Port Washington proper. Does anything change?
Very little. Manorhaven, Baxter Estates, Port Washington North and Sands Point are separate incorporated villages, so the percentages above describe the hamlet, not them. But the houses share the same peninsula and much the same weather, and state utility records list PSEG Long Island electric and National Grid gas in all four villages. The same PSEG Long Island rebates and EmPower+ rules apply, and we scope a house there exactly the way we would in the hamlet.
Free energy audit in Port Washington
In a Port Washington house we start with the heat: what fuel, what equipment and how it vents. Then the basement or lower level, with the rim joist and, on a slope, the exposed foundation wall; then the attic, its hatch or floor, the knee walls and slopes of a cape, and any ducts up there. In a townhouse we look at the party wall where it meets the attic. If the house is already tight and the problem is the equipment, we say so. Then a written scope and a price, no charge and no obligation.
Call 914-825-6824 or use our contact form. We are open 8am–8pm, seven days, and work out of New Rochelle, NY with a 100-plus in-house crew that never subcontracts.
Learn more
- Insulation contractors across Nassau County
- Insulation in Glen Cove
- Insulation in Mineola
- Insulating an older home
- Spray foam insulation
- What happens during an energy audit