The Home Insulators

Insulation Contractors in Nassau County, NY

Nearly half of Nassau County was built in two decades: 47.5% of its 477,860 housing units date from the 1940s and 50s, and the 1950s alone account for 34.6%. The median unit was built in 1955. Around that post-war core sit 19.5% built before 1940, 19.1% from the 1960s and 70s, 7.3% from the 1980s and 90s and 6.6% since 2000.

76.3% of units are single-family detached houses, 5.7% are in two-unit buildings and 5.9% in buildings of fifty or more, and 81.9% of occupied homes are owner-occupied. Gas heats 62.1% of homes and fuel oil 27.6%, but the oil share swings from 74.7% in Levittown to 10.0% in Long Beach. In an oil-heated house, air sealing and insulation pay back in oil that is never burned, and the leakiest houses pay back first.

The county is three towns and two cities. The north faces Long Island Sound: Port Washington on the Cow Neck Peninsula, and Glen Cove, whose waterfront was built up as Gold Coast estates. The middle was the Hempstead Plains, farmed and grazed until the post-war boom, with the Long Island Rail Road running through Mineola, Westbury and Hicksville. Valley Stream and Elmont meet the Queens line, and the South Shore runs east from Baldwin through Merrick, Bellmore and Wantagh to the Massapequas, with canals cut toward the bay and Long Beach on its barrier island. The 43 place pages carry the detail.

The Nassau County places we work in

Town of Hempstead

  • Baldwin — 85.6% detached; 19.5% built in the 1940s and 24.6% oil heat.
  • Bellmore — 22.7% built in the 1960s; 92.9% detached, 68.0% gas heat.
  • East Meadow — 13.4% built in the 1980s and 90s; 35.3% gas heat.
  • Elmont — at the Queens line: 10.5% two-unit buildings, 90.1% built before 1980.
  • Floral Park — median home from 1939 or earlier, the oldest of the 43.
  • Franklin Square — 11.1% two-unit buildings and 4.7% heat with bottled gas.
  • Freeport — Freeport municipal electric (village-owned); 13.3% of units in fifty-plus buildings.
  • Garden City — 36.8% from the 1950s, 0.5% two-unit, 78.3% gas heat.
  • Village of Hempstead — 45.8% owner-occupied, the lowest of the 43; 15.4% from the 1970s.
  • Levittown — 40.3% built in the 1940s; 20.1% gas heat, the least of any place listed.
  • Lynbrook — 23.4% in two- to four-family buildings, the most of the 43.
  • Merrick — 95.7% detached, 95.9% owner-occupied, 21.1% built in the 1960s.
  • North Bellmore — 25.6% built in the 1960s, second only to Woodmere.
  • North Merrick — 1.2% electric heat, the lowest on the list; 38.6% oil.
  • North Valley Stream — 5.6% in three- and four-unit buildings; 64.7% gas heat.
  • North Wantagh — 77.3% from the 1940s and 50s; 7.5% electric heat.
  • Oceanside — 11,268 units, 18.2% built in the 1960s, 69.8% gas heat.
  • Rockville Centre — Rockville Centre municipal electric (village-owned); median home from 1944.
  • Roosevelt — 17.8% two- to four-family; 12.1% built in the 1980s and 90s.
  • Salisbury — 3.2% solar heat, the top solar share listed; 9.1% attached.
  • Seaford — 13.7% pre-1940, 8.7% built in the 1970s, 93.2% detached.
  • Uniondale — 72.0% owner-occupied; 8.1% in buildings of 20 or more.
  • Valley Stream — 12,943 units; 20.2% from the 1960s and 70s, 67.2% gas.
  • Wantagh — 94.6% detached; 26.3% from the 1960s and 70s.
  • West Hempstead — 92.2% detached, 94.5% built before 1980, 68.1% gas heat.
  • Woodmere — 39.3% from the 1960s and 70s, more than any other place listed.

Town of North Hempstead

  • Mineola — 19.3% in fifty-plus buildings, 55.6% detached, 9.9% electric heat.
  • New Hyde Park — 83.5% gas heat, the highest of the 43; 10.1% two-unit.
  • North New Hyde Park — 46.1% built in the 1940s alone, the top 1940s share listed.
  • Port Washington — 11.1% built since 2000; 12.8% in buildings of 20 or more.
  • Westbury — 10.6% built since 2000 and 27.8% oil heat.

Town of Oyster Bay

  • Bethpage — 12.0% built in the 1980s and 90s; 79.5% detached.
  • East Massapequa — 4.5% attached, 32.4% oil heat, 80.8% built before 1980.
  • Hicksville — 13,637 units, 93.9% detached, 14.4% built in the 1940s.
  • Jericho — median 1961, the youngest of the 43; 15.3% electric heat.
  • Massapequa — 96.8% detached, 96.9% owner-occupied, 19.2% from the 1960s.
  • Massapequa Park — 98.0% owner-occupied, the highest share of the 43.
  • North Massapequa — 94.7% detached and 0.0% in buildings of 20 or more.
  • Plainview — 9,136 units; 16.4% from the 1960s, 32.8% oil heat.
  • South Farmingdale — 0.6% built since 2000, the smallest share of the 43.
  • Syosset — 22.4% from the 1960s and 70s; 7.0% electric heat.

The two cities

  • Glen Cove — bordered on three sides by the Town of Oyster Bay; 20.6% two- to four-family.
  • Long Beach — 31.9% of units in buildings of 20 or more; 13.3% electric heat.

The houses across Nassau County

The county’s house is the post-war cape or ranch, and Levittown set the pattern. Levitt & Sons built it for returning veterans from 1947 to 1951, on concrete slabs with radiant heating pipes and an unfinished “expansion attic,” and 85.9% of its units date from the 1940s and 50s. With no basement, the work is the attic, the low eave and whatever the owners finished upstairs. The same era dominates Salisbury (80.4%), North New Hyde Park (80.3%) and North Wantagh (77.3%). A cape’s second floor is boxed in by knee walls, with floor joists running under them into the ceiling below. These are oil places too: 74.7% of Levittown’s homes heat with oil, 59.4% of Salisbury’s and 54.5% of North Wantagh’s.

Older houses cluster in the villages. Floral Park is 52.5% pre-1940, Rockville Centre, a railroad commuter town by the early 1900s, 45.4%, Lynbrook 45.3% and Garden City 37.1%; Garden City began when Alexander Turney Stewart bought part of the Hempstead Plains in 1869. There we expect balloon framing, stud bays open from cellar to attic, attic bedrooms, and wiring to check before a wall is filled. Two-families come with the older stock: 23.4% of Lynbrook’s units are in two- to four-family buildings, 21.4% of Long Beach’s and 20.6% of Glen Cove’s, each scoped as one building with its shared stair and the floor between households.

The 1960s and 70s, 19.1% of the county, peak in Woodmere at 39.3%, then the Village of Hempstead at 29.8%, North Bellmore 29.4% and Bellmore 28.4%. That is split-level and high-ranch country: a bedroom wing over the garage, attics at different heights, a rim joist exposed where the levels step, and in a high ranch a band joist ringing the house at grade above a half-buried lower level.

Along the bay, water shapes the job. Hurricane Sandy in 2012 flooded southern Oceanside, sent floodwater along Massapequa’s canals, which run a mile inland, and damaged houses across Long Beach. Where a lower level or crawl space has taken water, we insulate above the flood line with assemblies that can dry.

North Shore houses run larger. Glen Cove’s waterfront was built as Gold Coast estates, most of them out of single-family use by the mid-20th century. Newer building is scattered: Uniondale is 20.3% built since 2000, the most of the 43, and Jericho is 15.5% from the 1980s and 90s and 12.3% attached. Those houses have full walls, so the losses move to attic ducts, cathedral ceilings, bonus rooms over garages and townhouse party walls.

Apartments concentrate in a few places: 34.7% of the Village of Hempstead’s units are in buildings of 20 or more, 31.9% of Long Beach’s and 24.5% of Rockville Centre’s. The roof and walls of a co-op, condominium or rental building serve every unit, so insulating them is the decision of the building’s owner or board.

We seal before we insulate

Insulation resists heat moving through a ceiling or a wall. Air leaking through a gap carries its heat straight past, so a deep attic over open bypasses still leaves drafty rooms.

In a Nassau cape the order is: block the joist bays under the knee walls, put a rigid air barrier on the attic side of each knee wall, baffle the slopes, then seal the top plates, flue and plumbing openings, bath fans and hatch before any insulation goes in. In a Levitt slab house the eaves come first; in a high ranch, the band joist all the way around.

If a quote specifies a depth of insulation and never mentions air sealing, it is half a job.

What insulation costs in Nassau County

Most of our projects run between $3,500 and $12,500. In Nassau the era sets the number: a cape’s knee walls, slopes and flat attic are three spaces to seal where a ranch has one; a split or high ranch adds band joists and a garage ceiling; a pre-war village house adds attic rooms and wall bays; a two-family is priced as one building. Closed cell spray foam goes where its air seal or R-value per inch earns the cost, and loose-fill takes the open attic floor. Our guide to spray foam insulation cost explains the price.

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 Nassau County

In New York the electric company decides which insulation programs a home can use. PSEG Long Island, which runs the grid for LIPA, supplies the Towns of Hempstead, North Hempstead and Oyster Bay and both cities, with two exceptions: the Village of Freeport has Freeport municipal electric (village-owned) and the Village of Rockville Centre has Rockville Centre municipal electric (village-owned).

National Grid is the only gas company. Most homes are on its lines in villages such as Floral Park, Garden City and Valley Stream. In Bellmore, Bethpage, East Meadow, Franklin Square, Hicksville, Jericho, Massapequa, Plainview, Port Washington, Roosevelt, Seaford, Syosset, Uniondale and Wantagh it runs on many streets, not every street, and in Levittown gas lines reach only parts of the hamlet; many homes there heat with oil, propane or electricity.

NYSERDA’s Comfort Home program is not open to PSEG Long Island homes. Their lane is the utility’s own: 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 that includes a blower door test. Oil, gas, propane and electric heat all qualify, which matters where 27.6% of homes burn oil, and the insulation must go in with comprehensive air sealing.

Freeport and Rockville Centre sit outside LIPA’s territory, so PSEG Long Island’s rebates are not the route there, and NYSERDA’s Comfort Home manual says homes with municipal electric service are not eligible for its package incentives. In either village, check with your village electric department and the MyEnergy portal.

National Grid’s Long Island insulation rebate program is not taking new applications; income-eligible households go through EmPower+. If your household income is under Nassau’s EmPower+ limit, 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 for a family of four), or half the cost up to $7,000 for moderate-income households (below $131,900 for four), through an EmPower+ contractor. Renters can apply, and Long Island households should check eligibility on the MyEnergy portal.

Each program pays through its own participating contractors, so confirm 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. Every program is laid out in our New York and New Jersey rebate guide.

Code and climate in Nassau County

86.1% of Nassau’s housing was built before 1980, from 96.0% of New Hyde Park down to 73.1% of Uniondale. New York’s first statewide energy code took effect on 1 January 1979. Nassau County is Climate Zone 4.

Since 31 December 2025, new houses have been built to the 2025 Energy Conservation Construction Code of New York State: R-49 ceilings, or R-38 across the whole ceiling where it keeps its full, uncompressed 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 no more than 3.0 air changes per hour at 50 pascals.

An existing house is treated differently. Unaltered parts need not comply, New York’s code does not require a blower door test when you insulate an existing home, and any cavity the work exposes must be filled to full depth. On a low post-war roof, getting full-height insulation over the plate takes baffles at the eave. 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 Nassau County

Do you install insulation in Nassau County, NY?

Yes, across all three towns and both cities, from Elmont and Valley Stream at the Queens line to the Massapequas, and from Port Washington and Glen Cove on the North Shore to Long Beach on its barrier island. We seal and insulate post-war capes and Levitt houses, pre-war village houses and two-families, split-levels and high ranches, and newer colonials and townhouses, with spray foam, dense-pack and loose-fill. In apartment buildings, condominiums and co-ops, the building’s owner or board decides.

How much does insulation cost in Nassau County?

Most projects run $3,500 to $12,500. A cape usually costs more than a ranch of the same size, because its knee walls, slopes and flat attic are separate spaces to seal. A Levitt slab house is mostly attic and eave work; a split-level or high ranch adds the band joist and garage ceiling; a pre-war house in Floral Park or Lynbrook can add attic rooms and wall bays. Closed cell foam costs more per inch, so it goes only where it earns that. The walk-through and written price are free.

Are there insulation rebates in Nassau County?

For most homes, yes. PSEG Long Island 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. Comfort Home is not available to PSEG Long Island homes. In Freeport and Rockville Centre, which run village-owned electric systems, check with the village electric department and the MyEnergy portal. Income-eligible owners and renters can apply to EmPower+. The federal 25C credit ended for work placed in service after 31 December 2025.

Which utility do I have in Nassau County?

Check the electric bill. PSEG Long Island supplies electricity to nearly the whole county: the Towns of Hempstead, North Hempstead and Oyster Bay, Glen Cove and Long Beach. The two exceptions are villages with their own systems, Freeport municipal electric (village-owned) and Rockville Centre municipal electric (village-owned). Gas, where a house has it, comes from National Grid: on most streets in villages such as Garden City and Floral Park, on many streets but not every street in hamlets such as Hicksville and East Meadow, and in only parts of Levittown.

Free energy audit in Nassau County

We start where each era leaks: the knee walls of a cape, the eaves of a slab house, the band joist and garage ceiling of a split or high ranch, the attic rooms and wall bays of a pre-war house, and in a two-family the shared stair and the floor between units. In an oil-heated home we check the boiler and chimney before we tighten the house. You get a written scope and a price, at no charge.

Call 914-825-6824 or use the 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.

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Insulation services in Nassau County, NY