98.0% of North Merrick’s 4,186 housing units are single-family detached houses. The remainder is a sliver: 1.1% attached, 0.4% in three- and four-unit buildings, 0.5% mobile homes, and no two-unit buildings at all. North Merrick is an unincorporated hamlet in the Town of Hempstead, near the South Shore, with the Meadowbrook State Parkway forming much of its western border with Roosevelt and Uniondale and the Southern State Parkway crossing it.
The median home dates from 1953; 9.4% were built before 1940, 24.3% in the 1940s and 47.5% in the 1950s, while only 2.4% has been built since 2000. 94.7% of occupied homes are owner-occupied. Heat comes mainly from gas and oil: 56.3% of homes burn utility gas, 38.6% fuel oil, 2.0% bottled gas and 1.2% electricity.
A detached house held by its owners for seventy years or more has usually grown. In North Merrick the room that was added, a family room across the back, a longer kitchen, an enclosed breezeway, is often the coldest room in the house, because it has a low-slope roof and no attic above it.
The houses we insulate in North Merrick
Camp Avenue, Jerusalem Avenue, Meadowbrook Road and Merrick Avenue all pass through the hamlet, and one house in four along its streets dates from the 1940s: 1,016 homes. A 1940s North Merrick house is usually a compact story or story-and-a-half, framed with board sheathing under its siding and walls that were often left empty. We confirm what is in them before deciding anything. Where the walls are empty and the wiring is sound, they can be dense-packed with cellulose through small holes.
The 1950s houses, 1,990 of them, are the capes and ranches. The cape’s upstairs sits inside its roof and loses heat at every edge: knee walls backed by open attic, joist bays that run out beneath them to the eave, sloped ceilings with a thin batt tight to the deck. The ranch loses across a long attic floor where the original insulation has sunk and thinned toward the eaves and the tops of the partitions are open underneath it.
The 392 homes built before 1940 are the ones where we expect plaster, possible balloon framing with bays open from cellar to attic, and old wiring that has to be checked before a wall or attic floor is covered. The 7.9% from the 1960s brings split-levels with a bedroom over the garage; the few houses built since 2000 have full walls, and their losses are attic ducts and bath fans.
The fuel mix shapes the payback. With 56.3% of homes on gas, most of North Merrick is on National Grid gas lines, and for those homes the return shows up on the monthly bill. The 38.6% on oil see it as fewer deliveries each winter, a figure that moves with the price of oil. An addition warmed by a separate electric heater adds its own line to the electric bill.
Rooms with no attic: the low-slope roofs over North Merrick additions
A family room or kitchen extension built onto the back of a 1940s or 50s house was commonly roofed with a shallow shed roof, pitched just enough to shed water and tucked under the eave of the original house. Inside, the ceiling was fastened straight to the underside of the rafters. There is no attic, only the depth of the rafters between the drywall and the roof deck, usually holding whatever batt went in the year the room was built.
That assembly fails in three ways. It is thin, so heat escapes upward in January and the roof’s heat pours down in July. It leaks, because every recessed light, ceiling fan box and skylight well is a hole into a cold cavity, and warm, damp room air that reaches the underside of a cold deck can condense there. And it connects: where the addition meets the house, the old eave and soffit are often boxed inside the new ceiling, so the addition’s rafter bays open into the main attic or straight to the outdoors through the old soffit vents.
How to fix it depends on what is being opened. When the roof is due for replacement, rigid insulation laid on top of the deck before the new roofing is the most complete answer, keeping the cavity below warm and dry; New York’s code table sets R-30 continuous for insulation placed entirely above the deck on new homes. When the ceiling is coming down for a renovation, closed cell spray foam against the underside of the deck seals and insulates the bays in one layer and controls vapor at the same time. When the room is finished and the roof is sound, the closed bays can sometimes be dense-packed through small ceiling holes, but only after the lights and penetrations are sealed and the cavity has been checked for past moisture, because packing a wet or unvented roof cavity can trap water against the deck. Sometimes the right call is to seal the ceiling now and insulate when the roof comes off.
The joint with the house gets closed in every case. We block and seal the rafter bays where they meet the old wall and eave, so the addition stops trading air with the main attic, and we look at the floor under the addition, whether slab or crawl space, before calling the room done.
We seal before we insulate
Insulation limits the heat that soaks through a ceiling or wall. It barely slows air, and air moving through a gap carries far more heat per square inch than the surface around it loses. Sealing comes first.
In a North Merrick cape with a back addition the order is: in the main attic, seal the partition tops, the chimney gap with sheet metal and high-temperature sealant, the plumbing vent and the ceiling boxes; block the floor bays under the knee walls and back the knee walls with an air barrier; seal the rafter bays where the addition meets the old eave. In the addition, seal every light, fan box and skylight well from below. Then the basement rim and sill. Then insulate each part by the method its cavity allows.
If a quote specifies a depth of insulation and never mentions air sealing, it is half a job.
What insulation costs in North Merrick
Most of our projects run between $3,500 and $12,500. An attic and rim job on a 1950s ranch is the smaller end of the range, and knee walls and slopes lift a cape above it. The low-slope addition moves the number most, and the method decides by how much: dense-packing closed bays from inside costs less than spray foaming an opened ceiling, and rigid insulation above the deck is priced with the roofer’s reroofing work. Filling the empty walls of a 1940s house is priced by the number of bays.
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 North Merrick
North Merrick’s electric company is PSEG Long Island, and National Grid supplies its gas. Comfort Home, NYSERDA’s market-rate program, is not open to homes on PSEG Long Island electric service, so North Merrick’s rebates run through PSEG Long Island.
PSEG Long Island lists a $2,500 insulation rebate, a $1,000 air-sealing rebate and a $500 duct-sealing rebate for market-rate single-family homes, with higher amounts for income-qualified homes and homes in state-designated disadvantaged communities. They are paid through its participating contractors after a free Whole House Energy Assessment, which includes a thermal scan and a blower door test. Under its 2026 rules, homes heated with oil, natural gas, propane or electricity are all eligible, insulation must be installed with blower-door-assisted air sealing, and ductwork in unconditioned space must be sealed.
National Grid’s Long Island insulation rebate program is not taking new applications; income-eligible households go through NYSERDA’s EmPower+, which can pay for air sealing and insulation at no cost up to $14,000 for lower-income households, or half the cost up to $7,000 for moderate-income households, through an EmPower+ contractor, with up to $1,600 more for air sealing, insulation and ventilation from federal HEAR funds. Long Island households should check eligibility on the MyEnergy portal.
Each program pays through its own participating contractors, so check 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 sets out the rest.
Code and climate in North Merrick
92.3% of North Merrick’s housing was built before 1980. The hamlet’s 1940s and 50s houses, and most of the additions behind them, went up before New York’s first statewide energy code took effect on 1 January 1979. Nassau County is Climate Zone 4.
New homes are built to the 2025 Energy Conservation Construction Code of New York State, effective 31 December 2025: R-49 in ceilings, or R-38 across the whole ceiling where that R-38 reaches full, uncompressed height over the wall top plate at the eaves; R-30 continuous where all the insulation sits above the roof deck; R-30 floors; basement and crawl space walls at R-15 continuous, R-19, or R-13 plus R-5 continuous; U-0.27 windows; and air leakage no greater than 3.0 air changes per hour at 50 pascals.
For the house you already own, the rules are narrower: its unaltered parts need not comply, and New York’s code does not require a blower door test when you insulate an existing home. Take an addition’s ceiling down, and the roof cavities it exposes are to be filled to full depth. ENERGY STAR recommends R-60 for an uninsulated attic in this zone and R-49 for one that already has 3 to 4 inches.
Common questions about insulation in North Merrick
Do you install insulation in North Merrick, NY?
Yes, throughout the hamlet, from the streets along the Meadowbrook State Parkway to Merrick Avenue. Most of our North Merrick work is in the 1940s and 50s houses that make up 71.8% of the housing: attic floors, capes’ knee walls and slopes, empty 1940s walls, basement rims, and the low-slope additions with no attic that are so often the coldest rooms. We also work on the pre-1940 houses after a wiring check and on 1960s split-levels.
How much does insulation cost in North Merrick?
Most projects run $3,500 to $12,500. The ranch attic and basement rim are the smaller jobs; a cape’s knee walls and slopes cost more. A low-slope addition moves the price most: dense-packing its closed ceiling costs less than foaming an opened one, and insulation above the roof deck is priced alongside the reroofing. Empty 1940s walls are priced by the bay. The walk-through and a written scope and price are free.
Are there insulation rebates in North Merrick?
Yes, through PSEG Long Island, North Merrick’s electric company. It lists a $2,500 insulation rebate, a $1,000 air-sealing rebate and a $500 duct-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 available 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 insulation credit.
The family room on the back of our North Merrick house has a low sloped ceiling and no attic. Can it be insulated without tearing it apart?
Often, yes, but it depends on the roof. If the ceiling cavity is dry and has no history of leaks, we seal every light and fan box from below and dense-pack the rafter bays through small holes that are patched afterward. If the roof is due for replacement, rigid insulation on top of the deck is the better answer and the ceiling stays untouched. Either way, the bays are blocked where the addition meets the old eave of the house, which is where much of the cold air gets in.
Free energy audit in North Merrick
We start in the addition, if there is one: the ceiling, its lights and fan box, any skylight, and a look at the cavity through a fixture opening; then the joint with the main house from the attic side. Then the main attic, the knee walls of a cape, the outside walls of a 1940s house at an outlet, and the basement rim, sill and heating system. If the main attic is fine and the family room is the problem, we tell you. You get a written scope and a price, free and without 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 Merrick
- Insulation in North Bellmore
- Insulation in Uniondale
- Roof insulation
- Rigid board insulation
- Spray foam insulation