20,501 people live in North Bay Shore’s 4,519 occupied homes, and 85.1% of its 4,847 homes are detached houses. Those two numbers describe a lot of full houses, and a full house puts more moisture into its air, and more use through its bath fans, doors and basement, than the same house with two people in it. That changes how a North Bay Shore house should be sealed.
North Bay Shore is a hamlet in the Town of Islip, and it is a separate place from Bay Shore, which is covered on its own. The Sagtikos State Parkway forms its western boundary, the Southern State Parkway its southern boundary, and the Long Island Rail Road’s Ronkonkoma Branch most of its northern boundary. The area known as Pine Aire lies inside it, and for the 2010 count the hamlet was enlarged to take in the part of neighboring Brentwood west of Candlewood Road.
The median home dates from 1967, and 74.3% of homes were built before 1980. 82.8% of occupied homes are owner-occupied. Utility gas heats 50.1% of occupied homes, fuel oil 33.1%, bottled gas 10.1% and electricity 6.6%, so a large share of the hamlet buys its heat by the delivery, from an oil truck or a propane truck. National Grid gas runs on many North Bay Shore streets, but not on every one.
The houses we insulate in North Bay Shore
Before the suburbs arrived, North Bay Shore was farms. The 1950s built 1,163 homes on that land, 24.0% of today’s stock, and the 1940s another 245: capes and ranches. The cape’s upstairs sits behind short knee walls, with the floor bays under them open to the eave and the sloped ceilings packed with a thin batt and no vent space. The ranch has one long, low attic of loose-fill that has settled over the decades, with the flue chase and every light box open through it. Many capes have gained a dormer or a rear addition since, and each addition brings its own small attic and a seam where it meets the original house.
The 1960s added 1,139 homes and the 1970s 851. These are high ranches and splits, with a garage under a bedroom, a lower level partly in the ground, and a rim joist that runs bare around the whole house just above the foundation. Where the lower level is finished and lived in, the rim joist, the garage ceiling and the foundation wall sit right beside where someone sleeps. Those are the cold spots, along with the long attic plane over the bedroom level.
The 1980s built 351 homes and the 1990s 453, together 16.6% of the hamlet, and 9.1% has been built since 2000. Those houses have insulated walls; their losses are at the attic hatch, the bath fans, the ducts and any bonus space over a garage. North Bay Shore also has 235 townhouses and other attached homes and 118 homes in buildings of twenty to forty-nine units, where the roof and attic usually belong to an association or an owner rather than to one household.
In the 33.1% of homes on oil and the 10.1% on propane, the payback on sealing comes as fewer deliveries. Neither fuel arrives through a meter you can forget about; each fill is a bill, and a house that holds its heat stretches the time between them for as long as it stays on that fuel.
Full houses: moisture, fans and a tighter North Bay Shore home
People put water into indoor air every day: showers, cooking, laundry, drying clothes, breathing. The more people under one roof, the more water. In a leaky house much of that moisture rides out with the warm air through gaps at the top of the house, into the attic, and on a cold night it condenses on the underside of the roof deck. The dark staining and frost on attic sheathing we find in February is often that moisture, not a roof leak.
Sealing the attic floor stops that path, which is the point, and it means the water has to leave another way. So in a North Bay Shore house ventilation is part of the insulation job, not an afterthought. Every bath fan gets ducted all the way outdoors, never into the attic or a soffit, with an insulated duct and a damper at the end. A range hood that vents outdoors gets its duct sealed. The dryer vent runs the short way out, with sealed joints. And a bathroom that serves a full household each morning needs a fan that actually moves air, on a timer that keeps it running after the shower stops.
A lived-in lower level needs the same thinking. A bedroom or family room partly below grade stays drier once the rim joist is sealed and insulated and the foundation wall is covered with a material that does not hold water, such as rigid foam board or closed cell foam, rather than fiberglass batts against the concrete.
Tightening a house also affects everything in it that burns. With oil, propane and gas all common here, a sealed house needs its burner, boiler and water heater drawing combustion air properly and venting up the flue, and a working carbon monoxide alarm on each floor. We look at those before we recommend sealing anything.
We seal before we insulate
Insulation slows heat moving through a ceiling or wall. It does not stop air, and air moving through a gap takes heat and moisture with it.
In a North Bay Shore high ranch the sequence runs: seal the top plates, wire and pipe holes and light boxes across the attic floor; seal and duct out the bath fan housings; close the gap at the flue with sheet metal and high-temperature sealant; weatherstrip and insulate the hatch; set baffles at the eaves; then blow the attic to depth. Downstairs, seal the sill, insulate the rim joist, and seal and fill the garage ceiling under the bedroom. In a 1950s cape the knee walls come first: block the floor bays, air-seal the back of each knee wall, baffle the slopes, then insulate.
If a quote specifies a depth of insulation and never mentions air sealing, it is half a job.
What insulation costs in North Bay Shore
Most of our projects run between $3,500 and $12,500. A 1950s ranch with one attic and a rim is toward the lower end. A 1960s or 70s high ranch prices in the middle once the attic, the rim, the garage ceiling and the bath fan ducting are counted. A cape with a dormer and a rear addition, several small attics and knee walls, or a high ranch whose lower level walls need insulating, runs toward the top. Venting fans outdoors adds to the cost, and it is not optional in a tightened house.
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 Bay Shore
PSEG Long Island supplies electricity to North Bay Shore, and National Grid supplies gas on the streets that have gas lines. Because the electric company is PSEG Long Island, its rebates are the main route for market-rate homes.
PSEG Long Island’s rebates begin with a free Whole House Energy Assessment that checks insulation and drafts and includes a thermal scan and a blower door test. For market-rate single-family homes it lists a $2,500 insulation rebate and a $1,000 air-sealing rebate, with higher amounts for income-qualified homes and homes in state-designated disadvantaged communities, and its rules name oil, natural gas, propane and electric heat as eligible. Insulation must be accompanied by comprehensive air sealing, and the rebates are paid only through its participating contractors, so check a contractor on PSEG Long Island’s list before signing anything.
National Grid’s Long Island insulation rebate program is not taking new applications; income-eligible households go through NYSERDA’s EmPower+, open to owners and renters of one- to four-family homes. It covers 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. For a Suffolk household of three the lower tier runs to $89,063 and the moderate tier to below $118,750; larger households have higher limits. Long Island households should check eligibility on the MyEnergy portal.
PSEG Long Island’s REAP program offers a free in-home energy survey to customers at or below its income guidelines ($131,900 for a household of four) who have not had a REAP visit in five years, and may install door sweeps, attic hatch covers and a smart thermostat at no cost. It does not install insulation. The federal insulation tax credit (Section 25C) ended for work placed in service after 31 December 2025, and New York has no state tax credit for insulation. See our New York and New Jersey rebate guide.
Code and climate in North Bay Shore
74.3% of North Bay Shore’s homes were built before 1980. New York’s first statewide energy code took effect on 1 January 1979, after the farms had already become capes, ranches and high ranches. Suffolk County is Climate Zone 4.
Under the 2025 Energy Conservation Construction Code of New York State, in effect since 31 December 2025, a new house needs R-49 in the ceiling, with R-38 accepted over the full ceiling where its uncompressed height extends over the wall top plate at the eaves; R-30 in 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.
Existing houses are not pulled up to those numbers. Unaltered parts need not comply, and New York’s code does not require a blower door test when you insulate an existing home. Insulation may not be reduced, and a cavity exposed by an alteration must be filled to full depth. ENERGY STAR recommends R-60 for an attic with no insulation and R-49 for one with 3 to 4 inches.
Common questions about insulation in North Bay Shore
Do you install insulation in North Bay Shore, NY?
Yes, throughout the hamlet, including Pine Aire and the section west of Candlewood Road. Most of the work is the 1950s capes and ranches and the 1960s and 70s high ranches and splits: attics, rim joists, garage ceilings, knee walls and lower-level foundation walls, with bath fans ducted outdoors as part of the job. We also insulate newer houses with attic, duct and hatch problems. If you live in Bay Shore proper, we work there too.
How much does insulation cost in North Bay Shore?
Most projects run $3,500 to $12,500. A 1950s ranch with a single attic and a rim is at the lower end. A high ranch with its attic, rim, garage ceiling and fan ducting is mid-range. A cape with dormers, additions and several small attics, or a lived-in lower level whose foundation walls need insulating, costs more. Ducting fans outdoors adds a little, and a tighter house needs it. The written scope and price come after a free walk-through.
Are there insulation rebates in North Bay Shore?
Yes. PSEG Long Island, the electric company, 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 and propane heat both qualify. National Grid’s Long Island program is closed to new applications, and income-eligible owners and renters 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 credit.
Will sealing our North Bay Shore house cause condensation on the windows?
It can if the moisture has nowhere to go, which is why fans are part of the job. Light fogging at the bottom of the glass on the coldest mornings in a busy house is common and clears once a fan runs. Water running down the glass and pooling on the sill means the house needs more exhaust: longer fan run times, a fan in a bathroom that lacks one, or a range hood that vents outside. Tell us if it happens the first winter. Old single-pane or failing windows fog more than good ones.
Free energy audit in North Bay Shore
We start in the attic, looking at the sheathing for frost stains and dark patches, at where each bath fan actually ends, and at the top plates and the flue. Then we go down to the rim joist, the garage ceiling and any lived-in lower level, and look at how the burner, boiler or water heater gets its air. You get a written scope and price, with no charge and 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 Bay Shore
- Insulation in Central Islip
- Insulation in Deer Park
- Air sealing
- Attic insulation
- Basement insulation