East Northport is split almost down the middle between the gas main and the oil tank. 46.8% of occupied homes heat with utility gas and 45.7% with fuel oil, with 4.1% on electricity and 2.2% on bottled gas. The houses those two fuels heat are old: the median home was built in 1958, 89.0% of the hamlet’s 7,590 homes went up before 1980, and only 4.7% have been built since 2000.
35.0% of the stock dates from the 1950s and 24.4% from the 1960s, but 12.9% is older than 1940, left from the farm and railroad years. 91.0% of homes are detached houses and 89.0% of occupied homes are lived in by their owners. East Northport is a hamlet in the Town of Huntington, the largest community in that town by land area, and every house in it buys electricity from PSEG Long Island.
That split changes how a saving arrives. On an oil house it is counted in gallons, and what a gallon is worth moves from one winter to the next; on a gas house it shows on the National Grid bill. The leaks that waste either fuel sit in the same places.
The houses we insulate in East Northport
The land was bought from Asharoken, chief of the Matinecock, on 30 July 1656, and two settlements grew on it: Larkfield on the north side, near Vernon Valley, and Clay Pitts on the south, named for deposits of red clay that settlers made into brick. The farms between them fed New York City and Brooklyn. In 1873 the Long Island Rail Road opened a station at Larkfield Road and Bellerose Avenue that conductors called “East of Northport,” and in 1910 the Larkfield post office took the name. After the Second World War the farmland became suburbs.
The boom left 562 homes from the 1940s and 2,655 from the 1950s, 42.4% of the hamlet together, mostly capes and ranches. Many capes were sold with the upstairs unfinished, and owners completed them in different decades with different materials. The failure is the same in all of them: a short knee wall with nothing stopping air on its attic side; floor joists running out under it to the eave, open to outdoor air; rafter slopes packed tight with no vent space; and a flat attic too shallow to stand in. The bedroom under that assembly is the cold one in January and the hot one in July.
The ranch fails more simply. Its attic is one long, low plane, the loose-fill in it has been settling for sixty or seventy years, and the depth thins to almost nothing at the eave where the rafters meet the wall. Through that plane run the chimney, the plumbing vent, the ceiling fixtures, the top plate of every interior wall and a pull-down stair with no weatherstrip. Heat leaves through all of them at once.
The 1960s added 1,849 homes and the 1970s 712, mostly high ranches and splits. Those put bedrooms over a garage and a half-buried lower level, so the garage ceiling, the rim joist at head height in the family room and any cantilevered overhang belong on the scope with the attic.
The oil share adds two items. An oil house has a masonry chimney rising through the attic, and the gap between it and the surrounding framing is usually open; that gets closed with sheet metal and a fire-rated sealant, never with insulation packed against the masonry. And the cellar holding the boiler and tank is usually unfinished, which puts the rim joist within easy reach.
The rest of the stock is small: 284 homes in two-unit buildings, which we scope as one building because the stair and the floor between units are shared; 82 in buildings of fifty or more, whose envelopes belong to the building’s owner; and a few houses built since 2000, where the walls are full and the work is ducts and the room over the garage.
Farmhouses and their additions: where the old house meets the new
977 East Northport homes predate 1940, and few of them are still the size they were built. A farmhouse core picks up a kitchen wing, a 1950s addition across the back, a dormer, a family room over a crawl space. Each part was framed to its own decade’s habits, with its own roof and attic, some with no access at all.
The core is usually balloon-framed: the studs run from the sill in the cellar up to the rafters, with nothing to stop air climbing the cavity into the attic. If the wiring in those walls is still knob-and-tube, it is replaced before anything is blown in. The seams leak most. Where an addition was built against the old house, the old exterior wall ends up inside the new attic, still wearing its siding and open at the top of every stud bay. Where the addition sits over a crawl space, that space often opens into the main cellar.
So we scope an added-on farmhouse as several small buildings joined together. Every attic gets found and reached, sometimes by cutting a hatch; the old wall inside each addition’s attic gets sealed and covered; balloon-frame cavities get blocked at top and bottom before the walls are dense-packed; and each crawl space is either insulated at its walls or cut off from the house at its floor. A quote that prices one attic on a house with four roofs has missed most of the house.
We seal before we insulate
Insulation slows heat conducting through a ceiling or a wall. Air moving through a gap carries heat straight around it, and an old house with a cellar at the bottom, open cavities in the middle and an attic at the top draws air like a chimney all winter.
In an East Northport cape the order is: block the joist bays under the knee wall where they run out to the eave; put a rigid air barrier on the attic side of the knee wall; seal the top plates, the chimney gap, the plumbing vent and the fixture boxes in the flat attic; baffle the slopes wherever they can be reached; then insulate the knee wall, the slopes and the flat. After that comes the rim joist in the cellar. In a ranch the whole attic plane is sealed end to end before any loose-fill goes down.
If a quote specifies a depth of insulation and never mentions air sealing, it is half a job.
What insulation costs in East Northport
Most of our projects run between $3,500 and $12,500. In an East Northport cape the number moves with the feet of knee wall and eave to block and whether the slopes can be reached. A 1950s ranch with one open attic sits toward the lower end. An added-on farmhouse sits higher, because every addition brings its own attic and seam, and balloon-framed walls take blocking before they can be filled. For the foam side of the number, see what spray foam costs.
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 East Northport
East Northport’s electric company is PSEG Long Island, and its gas company is National Grid, whose gas is available on many streets but not all of them; an oil-heated house may sit on a street with no main. Because the electric company is PSEG Long Island, NYSERDA’s Comfort Home program is not available to East Northport homes.
PSEG Long Island lists a $2,500 insulation rebate and a $1,000 air-sealing rebate for market-rate single-family homes, plus $500 for duct sealing, with higher amounts for income-qualified homes and homes in state-designated disadvantaged communities. Oil, gas, propane and electric heat are all eligible. The rebates are paid through PSEG Long Island’s participating contractors after a free Whole House Energy Assessment, which includes a check of insulation and drafts, a thermal scan and a blower door test, and the insulation must go in with blower-door-assisted air sealing.
National Grid’s Long Island insulation rebate program is not taking new applications; income-eligible households go through EmPower+. NYSERDA’s EmPower+ program can pay for air sealing and insulation at no cost up to $14,000 for lower-income households (at or below $98,925 a year for a Suffolk family of four) or half the cost up to $7,000 for moderate-income households (below $131,900 for four), through an EmPower+ contractor, and renters can apply too. Long Island households should check eligibility on the MyEnergy portal.
The federal insulation tax credit (Section 25C) ended for work placed in service after 31 December 2025, so there is no federal insulation credit on a 2026 job; be wary of anyone still advertising it. New York has no state tax credit for insulation. The details are in our New York and New Jersey rebate guide.
Code and climate in East Northport
89.0% of East Northport’s homes were built before 1980. New York’s first statewide energy code took effect on 1 January 1979; the farmhouses and the post-war capes and ranches went up long before it. Suffolk County is Climate Zone 4.
The 2025 Energy Conservation Construction Code of New York State has been in force since 31 December 2025. For a new house it calls for R-49 in the ceiling, or R-38 over the entire ceiling where the uncompressed R-38 reaches full height over the wall top plate at the eaves; R-30 floors; basement and crawl space walls at R-15 continuous, R-19, or R-13 plus R-5 continuous; windows at U-0.27; and no more than 3.0 air changes per hour at 50 pascals.
In an existing house, unaltered parts do not have to comply, so insulating a cape’s attic does not pull its walls or windows into that table, and New York’s code does not require a blower door test when you insulate an existing home. Where an alteration opens roof or wall cavities, the exposed cavities must 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 down.
Common questions about insulation in East Northport
Do you install insulation in East Northport, NY?
Yes. Most East Northport work is the 1940s and 50s cape and ranch, 42.4% of the hamlet’s homes: knee walls with nothing behind them, joist bays open to the eave, settled attic floors and cellar rim joists. We also do the 1960s high ranches and splits, the older farmhouses with their additions and separate attics, and the few houses built since 2000, where the work is ducts and the room over the garage.
How much does insulation cost in East Northport?
Most projects run $3,500 to $12,500. A ranch with one attic and an open cellar rim sits toward the low end. A cape costs more when its knee walls, eaves and slopes are part of the scope, and an added-on farmhouse usually costs the most, because each addition has its own attic and its own seam to the old house, and balloon-framed walls need blocking before they can be filled. We give a written scope and a price after a free walk-through.
Are there insulation rebates in East Northport?
Yes. East Northport buys electricity from PSEG Long Island, which lists a $2,500 insulation rebate and a $1,000 air-sealing rebate for market-rate single-family homes, more for income-qualified homes, paid through its participating contractors after a free Whole House Energy Assessment. Oil-heated homes are eligible as well as gas-heated ones. Comfort Home is not available to PSEG Long Island homes. Income-eligible households can apply to EmPower+. The federal 25C credit ended for work placed in service after 31 December 2025, and New York has no state insulation tax credit.
We are replacing the roof on our East Northport house. Should the insulation be done at the same time?
Call before the roofer starts. Attic-floor work is done from inside and does not need the roof off. But if the roofer is replacing sheathing on a cape, its slopes and eaves are open from above for a few days: baffles can go in along the rafters, the bays can be filled to full depth, and the eave can be sealed properly. The roofer also sets the soffit and ridge vents, which have to line up with those baffles, and a bath fan venting into the attic can be run out through the new roof.
Free energy audit in East Northport
In an East Northport cape we go behind the knee walls first, then the flat attic, the eaves, the chimney gap and the cellar rim. In an added-on farmhouse we find every attic and crawl space, look at each seam, and check the wiring before we say anything about the walls. If a ranch’s attic is the whole job, we say so. Then a written scope and a price. No charge, no obligation.
Call 914-825-6824 or use our contact form. Open 8am–8pm, seven days. We work out of New Rochelle, NY with a 100-plus in-house crew that never subcontracts.
Learn more
- Insulation contractors across Suffolk County
- Insulation in Greenlawn
- Insulation in Elwood
- Insulation in Fort Salonga
- Insulating older homes
- Attic insulation
- Air sealing