877 of Westbury’s 5,431 housing units were built before 1940. That is 16.1% of the village, a pre-war core from the years when estate workers moved in and streets were mapped out, standing beside the houses of the boom that followed: 14.5% of the stock dates from the 1940s and 40.8% from the 1950s, when the village grew from 4,525 people in 1940 toward 14,757 in 1960 and used up its last undeveloped land. Westbury is an incorporated village, created by a 200-to-24 vote on 28 March 1932, lying mostly in the Town of North Hempstead with a small part in the Town of Oyster Bay.
71.6% of units are single-family detached houses, 10.2% are in two-unit buildings and 8.1% in buildings of fifty or more, and 78.1% of occupied homes are owner-occupied. The median home dates from 1955, and 10.6% of the stock has gone up since 2000. Gas leads the heating: 62.5% of homes burn utility gas, 27.8% fuel oil, 5.3% electricity and 2.9% bottled gas.
So Westbury holds three kinds of job: the pre-war village house with hidden air shafts, the post-war cape or ranch, and the two-family or apartment building, where the first question is who owns the roof.
The houses we insulate in Westbury
The village began moving away from farming in the late 19th century, when the very wealthy built mansions in what is now Old Westbury and Post Avenue became the commercial street that served their estates. Estate workers moved into the village, streets were mapped out and built, Post Avenue received electricity in 1902 and a water company followed in 1914. The village already had named sections: Grantsville, south of Union Avenue around the A.M.E. Zion church, fell inside the boundaries drawn in 1932, and the Hill across from Saint Brigid’s Church is where many Italian-American families still live. A house of that era is typically a framed house with plaster walls, a cellar and an attic under a steep roof.
A pre-war Westbury house loses heat upward through hidden shafts rather than across its walls. The space behind and beneath the stair, the gap framed around the chimney, the chase cut for a bathroom added later, and in a balloon-framed wall every stud bay can carry cellar air straight to the attic. The attic floor is often boards over thin or no insulation, and the stair to it is a door with daylight around it. Before any wall or floor bay is filled, we find out whether knob-and-tube wiring is still live in it.
The boom houses, 55.3% of the village from the 1940s and 50s together, are capes and ranches. The Westbury cape leaks at the edge of its upstairs: knee walls insulated only on the room side, floor bays running out to the eave under them, rafter slopes with no air channel. The ranch leaks across a single low attic whose insulation has settled away from the eaves and whose floor is pierced by every light box, partition top and plumbing vent. Both usually sit over a basement whose sill and rim were never sealed.
The 12.6% from the 1960s and 70s adds split-levels and high-ranches, each with its garage question: a bedroom floor of open joist bays over a split’s garage, or a high-ranch’s lower-level wall shared with the garage and insulated, if at all, on one side.
With 62.5% of homes on gas, most of the village is on National Grid gas lines, and the return on sealing and insulating arrives on the monthly gas bill and in rooms that hold their heat. The 27.8% still on oil see it as fewer deliveries. Either way, a tighter house can take a smaller boiler or furnace next time.
Houses, two-families and apartment buildings: where the work is in Westbury
By the mid-1950s the building boom had run out of land, and from the 1970s on the village became more urban and city-like. Besides the detached houses, 10.2% of units are in two-unit buildings, 2.4% in three- and four-unit buildings, 1.2% in buildings of five to nine, 2.7% in buildings of ten to nineteen, 2.0% in buildings of twenty to forty-nine and 8.1% in buildings of fifty or more.
The larger buildings are not a job we can sell to one resident. In a building of fifty units the roof, the exterior walls and usually the heating plant belong to the owner or the board, and any change to them is that owner’s decision. A drafty apartment in one is a matter for the building’s owner, manager or board, and if you are unsure which side of that line your building falls on, ask us on the phone.
The 552 units in two-unit buildings are our work, and we treat each building as one job. The attic sits over the upper unit only, but the stair hall, the floor between the apartments and the basement rim serve both, and sealing one apartment’s share of them leaves the leak in place. Where each unit has its own heating system, the savings land on two bills, which matters to an owner who rents one floor out.
The 10.6% built since 2000 went up in a village that had no open land left, so it is infill: newer houses and buildings whose walls were filled when they were framed. There the useful work is overhead, in attic ductwork, rooms over garages and bath fans that vent into the attic.
We seal before we insulate
Insulation slows the heat that passes through it and does little about air flowing around it. In an old house with open shafts from cellar to attic, warm air rises out of the top all winter and draws cold air in at the bottom, and insulation laid over the shafts does not stop the draft.
In a pre-war Westbury house the sequence starts at both ends of those shafts. In the cellar, seal the sill and rim and close the bottoms of any open wall bays and chases. In the attic, cap the chimney gap with sheet metal and high-temperature sealant, close the tops of the wall bays and the stair and plumbing chases, seal the light boxes, and weatherstrip the attic door. Then insulate the attic floor, and fill walls only after the wiring has been checked.
If a quote specifies a depth of insulation and never mentions air sealing, it is half a job.
What insulation costs in Westbury
Most of our projects run between $3,500 and $12,500. A 1950s ranch with a sealed and insulated attic and rim sits near the bottom of that range, and a cape adds knee walls and slopes. A pre-war house moves up with the number of shafts to close and whether the walls are filled, since each bay is dense-packed separately after the wiring is checked. A two-family is priced as one building on its roof area, its stair hall and its rim.
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 Westbury
Westbury’s electric company is PSEG Long Island, and most of the village is on National Grid gas lines. The electric company sets the rebate lane on Long Island, so NYSERDA’s Comfort Home program is not available to Westbury homes.
PSEG Long Island 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 after a free Whole House Energy Assessment with a thermal scan and a blower door test. Its 2026 rules require blower-door-assisted air sealing alongside the insulation, and they name single-family homes, so the owner of a Westbury two-family should ask PSEG Long Island what applies before counting on a rebate.
National Grid’s Long Island insulation rebate program is not taking new applications, and income-eligible households go through NYSERDA’s EmPower+, which serves owners and renters of one- to four-family homes. For one person in Nassau it can pay for air sealing and insulation at no cost up to $14,000 with income at or below $69,263, or half the cost up to $7,000 with income below $92,350, through an EmPower+ contractor. National Grid gas customers who meet those guidelines can also get no-cost home safety improvements through National Grid’s Weatherization Health and Safety Program, after applying to EmPower+ and completing a no-cost Health and Safety Assessment. Long Island households should check eligibility on the MyEnergy portal.
Every program pays through its own participating contractors, so confirm yours with the program before you sign. 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, and New York has no state tax credit for insulation. Our New York and New Jersey rebate guide covers the rest.
Code and climate in Westbury
84.1% of Westbury’s housing was built before 1980. The village’s estate-era houses and nearly all of its boom houses were standing long before New York’s first statewide energy code took effect on 1 January 1979. Nassau County is Climate Zone 4.
The 2025 Energy Conservation Construction Code of New York State has governed new homes since 31 December 2025. Its table asks for R-49 ceilings, or R-38 across the entire ceiling where that R-38 runs uncompressed at full height over the wall top plate at the eaves; R-30 floors; R-15 continuous, R-19, or R-13 plus R-5 continuous on basement and crawl space walls; U-0.27 windows; and a tested air leakage rate no higher than 3.0 air changes per hour at 50 pascals.
A standing house is not pulled up to that table. Parts of it left unaltered need not comply, and New York’s code does not require a blower door test when you insulate an existing home. If a renovation opens plaster walls or a ceiling, the exposed cavities are to be filled to full depth at no less than R-3 per inch. 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 Westbury
Do you install insulation in Westbury, NY?
Yes, throughout the village. Our Westbury work runs from the pre-war houses on the Hill, in Grantsville and on the older streets near Post Avenue, where the chimney gap, stair and plumbing chases and open wall bays come first, to the 1940s and 50s capes and ranches, the 1960s and 70s split-levels, and two-family houses scoped as one building. Apartments in the large buildings are the exception: their roofs and walls are the building owner’s to decide on.
How much does insulation cost in Westbury?
Most projects run $3,500 to $12,500. A 1950s ranch attic and rim are toward the lower end, and a cape adds its knee walls and slopes. A pre-war house costs more when the walls are filled, because the wiring is checked first and each bay is dense-packed on its own; closing its shafts adds less than most owners expect. A two-family is priced as one building. The walk-through is free and the price comes in writing.
Are there insulation rebates in Westbury?
Yes, through PSEG Long Island, the village’s electric company. It 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, paid through its participating contractors after a free Whole House Energy Assessment; two-family owners should ask PSEG Long Island what applies. Comfort Home is not open to PSEG Long Island customers. Income-eligible owners and renters can check EmPower+ on the MyEnergy portal. The federal 25C credit ended for work placed in service after 31 December 2025, and New York has no state credit.
The windows in our old Westbury house run with water on cold mornings. Will sealing and insulating make that worse?
Not if the moisture has somewhere to go. Water forms on the coldest glass when indoor air holds more moisture than that surface allows, and old single-pane sash are the coldest surfaces in the house. Tightening the house keeps more of that moisture inside, so bath and kitchen fans must vent outdoors and actually run, and a damp cellar needs attention. Water collecting between the sash and a storm window points the other way: warm, moist air is leaking out past the inner sash, which weatherstripping and sealing help stop.
Free energy audit in Westbury
In a pre-war Westbury house we follow the air from bottom to top: the cellar sill and rim, the bottom of the chimney and any open wall bays, then the attic door, the floor boards, the chimney gap and the tops of the chases. In a boom-era house it is the attic, the knee walls and the basement rim; in a two-family, the stair hall and the floor between units too. If the attic is fine and the chimney shaft is the real leak, we say so, and the written scope and price cost nothing.
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 Salisbury
- Insulation in Mineola
- Insulation in Hicksville
- Insulating older homes
- Wall insulation
- Basement and rim joist insulation