One Merrick home in five was built before 1940. That is 20.0% of the hamlet’s 7,331 housing units, 1,465 houses that went up before anyone insulated a wall as a matter of course, standing on the same South Shore streets as the capes, ranches and split-levels that followed. Merrick is an unincorporated hamlet in the Town of Hempstead, with its own station on the Long Island Rail Road’s Babylon Branch, and its median home dates from 1956.
The post-war decades still make up most of it: 10.0% of units date from the 1940s, 31.3% from the 1950s and 21.1% from the 1960s, while only 7.0% has been built since 2000, where the job is usually attic ductwork rather than walls. 95.7% of the housing is detached and 95.9% of occupied homes are owner-occupied. Heat is mostly gas — 70.7% of homes burn utility gas, 25.1% fuel oil, 2.1% electricity and 1.6% bottled gas — so in most Merrick houses the case for insulation is comfort and the monthly gas bill, and in the older ones it starts with the holes that decades of heating changes have left behind.
The houses we insulate in Merrick
The pre-1940 houses were built with plaster on wood lath, board sheathing and no insulation in the walls or the attic floor. They lose first at the attic floor: every partition is open at its top plate, a walk-up attic stair acts as a chimney, and whatever insulation is there went down decades later, thin and disturbed. Many of these houses have been extended since — a family room behind the kitchen, a second-floor addition, a sunroom on a slab — and the joint where the new roof meets the old one is often open air between two attics. Before anything goes into an old wall we check the wiring, because live knob-and-tube has to be dealt with first.
The 1940s and 50s houses, 41.2% of the hamlet together, are the capes and ranches. A Merrick cape fails behind its knee walls, where the bedroom floor’s joists run out to the eave under a strip of attic that is effectively outdoors, and at the slopes, where a thin batt is pressed against the roof deck with no channel for air. The ranch fails across one long attic floor: settled loose-fill, bare spots where someone walked to reach a fan, and uncapped wall tops. Both usually sit over a basement whose rim joist and sill are bare.
The 1960s share, 21.1%, brings split-levels and high-ranches. The split’s trouble is the garage with a bedroom above it and the side wall where the upper level rises past the lower roof. The high-ranch’s trouble is its lower level: a family room with the rim joist at eye level and a slab floor, and a garage beside it sharing a wall that is often uninsulated on the garage side.
Merrick is a South Shore hamlet, and 1.0 of its 5.2 square miles is water. Where a basement or crawl space stays damp for much of the year, that changes the materials below the first floor. Fiberglass batts pressed against a damp foundation or rim hold moisture and sag; closed cell foam does not absorb water and stops air at the same time, which is why it is what we use on a damp rim and on crawl space walls.
Old houses, newer boilers: the holes a heating change leaves
A Merrick house built before 1940 is almost certainly not heated by the equipment it was built with. Houses of that age have usually had their heating replaced more than once, and in a hamlet where 70.7% of homes now burn gas, many of those changes ended with a gas line to the basement. Each change cut holes through the house, and few were sealed afterward.
The biggest is the chimney chase. A masonry chimney passes up through each floor and the attic inside a framed opening, and the gap between the brick and the framing runs open from the cellar to the roof. When a newer boiler or furnace vents out through the side wall instead, the chimney is left cold and the gap is left open. Radiators taken out when ducts went in leave pipe holes through the floors. The ducts themselves climb to the second floor through chases cut in closets. An old oil fill pipe or vent line cut off at the foundation leaves a hole in the wall stuffed with whatever was handy.
Each is a path for warm air out and cold air in. We close the chimney gap with sheet metal and high-temperature sealant, leaving clearance around any chimney that still carries a flue, seal the old pipe holes from the cellar, cap the duct chases top and bottom, and plug the dead pipe penetrations in the foundation.
We seal before we insulate
Heat leaves a house two ways: through surfaces, which insulation slows, and through gaps, which insulation barely touches. Warm air rising out of the top of a Merrick house pulls cold air in at the bottom, so both ends get sealed.
In a 1950s Merrick cape we start in the basement: the rim joist and sill, the holes where the gas service, water line and any old oil pipes pass through the foundation, and the chimney gap at the cellar ceiling. Then the top: the chimney gap at the attic floor, the plumbing stack, the top plates, the ceiling fixtures and the bath fan, which should vent outdoors; then block the floor bays under the knee walls at the eave line, put an air barrier on the back of each knee wall and baffle the slopes. Only then do the knee walls, slopes and flat get insulated.
If a quote specifies a depth of insulation and never mentions air sealing, it is half a job.
What insulation costs in Merrick
Most of our projects run between $3,500 and $12,500. A pre-1940 Merrick house moves up the range when the walls are included, because the wiring gets checked first and the cavities are filled one by one, while closing a chimney chase and old pipe holes adds little. A cape is priced on its knee walls, slopes and flat, a ranch on attic area, and a split-level or high-ranch on its garage ceiling, its separate attic sections and the length of the rim. Closed cell foam on a damp rim or crawl space wall costs more than fiberglass and outlasts it there.
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 Merrick
Merrick’s electric company is PSEG Long Island, and most of the hamlet is on National Grid gas lines. Because the electric company sets the rebate lane, NYSERDA’s Comfort Home program is not available to Merrick homes; PSEG Long Island runs its own.
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. 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. Its 2026 rules require insulation to go in with blower-door-assisted air sealing and any ductwork in unconditioned space to be sealed, and they cover single-family homes heated with gas, oil, propane or electricity.
National Grid’s Long Island insulation rebate program is not taking new applications; income-eligible households go through EmPower+. NYSERDA’s EmPower+ can pay for air sealing and insulation at no cost up to $14,000 for lower-income households (in Nassau, 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. Owners and renters of one- to four-family homes can apply, and Long Island households should check eligibility on the MyEnergy portal.
Each program pays only through its own participating contractors, so check the contractor with the program before signing. 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. The details are in our New York and New Jersey rebate guide.
Code and climate in Merrick
88.4% of Merrick’s housing was built before 1980. New York’s first statewide energy code took effect on 1 January 1979, so the hamlet’s pre-war houses and most of its post-war ones were built with no state energy standard at all. Nassau County is Climate Zone 4. In Merrick itself the average monthly temperature runs from 31.7°F in January to 74.8°F in July, so the envelope works in both directions: keeping heat in over the winter and the attic’s heat out over the summer.
The 2025 Energy Conservation Construction Code of New York State has applied since 31 December 2025. For new homes it calls for R-49 ceilings, with R-38 accepted where it covers the whole ceiling at full, uncompressed 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 air leakage no greater than 3.0 air changes per hour at 50 pascals.
An existing Merrick house is not held to that table. Parts of the house left unaltered do not have to comply, and New York’s code does not require a blower door test when you insulate an existing home. Where a renovation opens roof or wall cavities, the code wants them filled to full depth at no less than R-3 per inch before they are closed again. 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 Merrick
Do you install insulation in Merrick, NY?
Yes, across the hamlet. Merrick work runs from the houses built before 1940, 20.0% of the stock, where we seal the chimney chase and old pipe holes and check the wiring before walls, to the 1940s and 50s capes and ranches, the 1960s split-levels and high-ranches with rooms over garages, and basements and crawl spaces that stay damp. That covers attic floors, knee walls and slopes, rim joists, garage ceilings, attic ductwork and walls where the wiring allows.
How much does insulation cost in Merrick?
Most projects run $3,500 to $12,500. A pre-1940 house costs more when its walls are included, because the wiring is checked first and each cavity is filled separately; sealing its chimney chase and pipe holes adds little. A cape is priced on knee walls, slopes and flat, a ranch on attic area, and a split-level on its garage ceiling and attic sections. Closed cell foam on a damp rim costs more than fiberglass. You get a written scope and price after a free walk-through.
Are there insulation rebates in Merrick?
Yes, through PSEG Long Island, Merrick’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. Gas- and oil-heated homes both qualify. Comfort Home is not open to PSEG Long Island customers. Income-eligible households 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 insulation credit.
Our Merrick upstairs is hot every July, even with central air. Will insulation help?
Usually, yes. A summer attic runs far hotter than the air outside, and that heat reaches the bedrooms two ways: down through a thin attic floor, and as hot attic air leaking in through the same gaps that let heat out in winter. If the air-conditioning ducts run through the attic, the cooled air warms before it reaches the rooms, and cold duct surfaces can sweat. Sealing the attic floor, adding depth, and sealing and insulating the ducts addresses all three. In a cape, the knee walls and slopes are the hot surfaces.
Free energy audit in Merrick
We start in the basement of a Merrick house, because that is where the history shows: the rim joist and sill, the chimney where it passes the cellar ceiling, and every hole an old heating system left in the floor or foundation, plus how damp the space stays. Then the garage ceiling on a split-level, and up to the attic: depth and evenness, the chimney gap at the top, the knee walls and slopes of a cape, the ducts. If the attic can wait and the chimney chase cannot, we say so. Then a written scope and a price, with 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 North Merrick
- Insulation in Bellmore
- Insulation in Freeport
- Insulating older homes
- Basement and rim joist insulation
- Air sealing