4,517 of Mastic’s 4,603 homes are detached houses, 98.1% of the stock, and fuel oil heats 86.1% of the occupied ones. Electricity heats 3.7% and bottled gas 3.4%, and Mastic has little or no utility gas service. The typical Mastic home is a stand-alone house burning oil, and whatever heat it loses has already been paid for by the gallon.
Mastic is a hamlet in the southeastern part of the Town of Brookhaven, and a separate place from Mastic Beach, which is covered on its own. It was called Forge until 1893. The Long Island Rail Road opened a station in 1882, and on 15 July 1960 moved the stop 7,010 feet west and renamed it Mastic–Shirley. The Poospatuck Indian Reservation of the state-recognized Unkechaug Nation lies within the community near its southern end, along the Forge River, and the northernmost section, known informally as Manor Park, runs from Sunrise Highway to Moriches-Middle Island Road just east of Brookhaven Airport.
The median home was built in 1977, and 62.1% of homes went up before 1980. 81.9% of occupied homes are owner-occupied, and the median owner-occupied home is valued at $370,500. On oil, the order of the work matters as much as the list.
The houses we insulate in Mastic
The 1970s built 1,658 homes, 36.0% of Mastic and the largest decade by far. They are mostly ranches, raised ranches and splits. The ranch has one low attic holding a few inches of original fiberglass or loose-fill over top plates that were never sealed, with the oil burner’s flue rising through it. The raised ranch and the split add a garage under a bedroom, a lower level set partly into the ground, and a rim joist running bare around the house just above the foundation. Where a house has hot-air heat, its ducts often run through the attic or under the floor, outside the insulated part of the house.
The 1980s built 747 homes, 16.2% of the stock, and the 1990s 314. Those houses have insulated walls and attic insulation laid to the thinner standard of their day, and their bigger losses are air: a hatch with no weatherstrip, light boxes, a plumbing chase, and duct joints whose tape has let go after thirty or forty years.
The older houses are fewer but distinct. 306 homes predate 1940, 269 date from the 1940s, 253 from the 1950s and 372 from the 1960s. Many are small: one story or a story and a half, over crawl spaces or low foundations, with shallow attics that pinch at the eaves and walls that are often empty. Where one has grown, each addition brings a separate roof and floor and a joint with the original house that nobody sealed.
The 590 homes from the 2000s, 12.8% of the stock, have full walls and code-era attics. What they need is usually targeted: the attic hatch, the bath fans, the ducts and a bonus room over the garage where there is one.
Doing it in stages: the order of work in a Mastic house on oil
Not every owner does the whole house at once, and on oil it does not have to be all or nothing. What matters is the order. Done out of order, a later stage can undo an earlier one, as when an attic is insulated one year and dug up the next to seal what should have been sealed first.
First, the attic plane. In a 1970s Mastic ranch or raised ranch, warm air rises and leaves through the top plates, light boxes, the plumbing stack, the hatch and the gap around the oil flue. Sealing those, then bringing the attic up to depth with baffles at the eaves, is usually the stage that saves the most oil for the money. Sealing and insulating belong in the same visit, because sealing under old insulation means moving it, and it should be moved once. If ducts run through the attic, their joints get sealed in this stage too, before new insulation covers them.
Second, the bottom of the house. The sill and rim joist where the house sits on its foundation, the garage ceiling under a bedroom, and in the older small houses the crawl space or the floor above it. Cold air drawn in low is what pushes warm air out high, so this stage makes the first one work better. Ducts in a crawl space or an unheated lower level get sealed and insulated here.
Last, walls and windows. Filling closed walls and replacing windows cost the most for each gallon saved. The best time for walls is when siding or drywall is coming off anyway, and new windows are more a replacement decision than an insulation one.
Two cautions apply to every stage. Have the oil burner’s draft and combustion air checked before work starts and again once the house is tighter. And if you plan to use PSEG Long Island’s rebates, ask before splitting the job, because its rules require insulation to be installed together with comprehensive air sealing.
We seal before we insulate
Insulation slows the heat that conducts through a ceiling or wall. It does not stop air, and on oil every cubic foot of warm air that escapes is burner time you bought.
In a 1970s Mastic split with an oil-fired hot-air furnace, we start with the ducts: mastic on the supply and return joints wherever they leave the heated space, and the furnace cabinet seams sealed. Then the attic: top plates, wire and pipe holes, the bath fan housing, the hatch, and a sheet-metal collar with high-temperature sealant around the flue, never foam; baffles at the eaves; then insulation to depth. Then the lower level: sill, rim joist, and the ceiling of the garage under the bedroom.
If a quote specifies a depth of insulation and never mentions air sealing, it is half a job.
What insulation costs in Mastic
Most of our projects run between $3,500 and $12,500. The first stage alone in a 1970s ranch, sealing the attic and bringing it to depth, sits toward the lower end. The whole house in one visit, with attic, rim, garage ceiling and ducts, runs from the middle of the range upward. An older small house with a crawl space, empty walls and additions under separate roofs costs more, because each piece is its own job. Doing everything at once costs less than the same work spread over three visits, since setup and access happen once, but the staged plan is there for owners who need it.
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 Mastic
Mastic’s electric company is PSEG Long Island, and the hamlet has little or no utility gas service. Homes on PSEG Long Island are not eligible for NYSERDA’s Comfort Home program; their rebates come from PSEG Long Island itself.
The first step is PSEG Long Island’s free Whole House Energy Assessment, which covers insulation and drafts with a thermal scan and a blower door test. PSEG Long Island lists a $2,500 insulation rebate, a $1,000 air-sealing rebate and $500 for duct sealing for market-rate single-family homes, with higher amounts for income-qualified homes and homes in state-designated disadvantaged communities. Its rules name oil heat as eligible and require all ductwork in unconditioned space to be sealed, which fits a hot-air house. The rebates are paid through its participating contractors, so check a contractor against PSEG Long Island’s list before you sign.
For income-eligible owners and renters of one- to four-family homes, NYSERDA’s EmPower+ pays for air sealing and insulation through an EmPower+ contractor, at no cost up to $14,000 for lower-income households or half the cost up to $7,000 for moderate-income households. A Suffolk household of four is in the lower tier at or below $98,925 and the moderate tier below $131,900. Mastic’s median household income, $106,491, sits between those two figures, reason enough for a family of four to check. Long Island households should check eligibility on the MyEnergy portal.
NYSERDA’s Green Jobs–Green New York program lends $1,500 to $25,000 over 5, 10 or 15 years, either on the utility bill or as a regular monthly loan, and the loans are paid back. The federal insulation tax credit (Section 25C) ended for work placed in service after 31 December 2025, so a 2026 job gets no federal credit, and New York has no state tax credit for insulation. Our New York and New Jersey rebate guide has more.
Code and climate in Mastic
62.1% of Mastic’s homes were built before 1980. New York’s first statewide energy code took effect on 1 January 1979, so the older houses and most of the 1970s ranches went up before it. Suffolk County is Climate Zone 4.
New homes are now built to the 2025 Energy Conservation Construction Code of New York State, in force since 31 December 2025: R-49 ceilings, with R-38 accepted across the whole ceiling where its full uncompressed height reaches over the wall top plate at the eaves; R-30 floors; R-15 continuous, R-19, or R-13 plus R-5 continuous for basement and crawl space walls; U-0.27 windows; and a tested maximum of 3.0 air changes per hour at 50 pascals.
An existing Mastic house is not held to that table. 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 cavities exposed by an alteration must be filled to full depth, which is why walls are best done when they are open. ENERGY STAR recommends R-60 for an uninsulated attic and R-49 where 3 to 4 inches are already down.
Common questions about insulation in Mastic
Do you install insulation in Mastic, NY?
Yes, across Mastic, including Manor Park up toward Sunrise Highway. Most of the work is the 1970s ranches, raised ranches and splits that make up 36.0% of homes and the 1980s houses that make up 16.2%: attics, rim joists, garage ceilings and ductwork in attics and crawl spaces. In the older small houses it is crawl spaces, shallow attics, additions and empty walls. We work the same way in Mastic Beach and Shirley.
How much does insulation cost in Mastic?
Most projects run $3,500 to $12,500. Sealing and insulating the attic of a 1970s ranch, the first stage, is toward the low end. The whole house at once, with attic, rim, garage ceiling and ducts, runs from mid-range upward. An older small house with a crawl space, empty walls and additions costs more. One visit costs less than three, but we will lay out stages if that works better. The written price follows a free walk-through.
Are there insulation rebates in Mastic?
Yes, mainly from PSEG Long Island, the electric company. It 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, and oil heat qualifies. Income-eligible owners and renters can check EmPower+ on the MyEnergy portal. Comfort Home is not available to PSEG Long Island customers. The federal 25C credit ended for work placed in service after 31 December 2025, and New York has no state insulation credit.
We may sell our Mastic house in a few years. Is insulation still worth doing?
Usually, if the work is the attic and the rim. On oil, the saving starts with the first winter’s deliveries rather than waiting for a sale, and a house without cold rooms is easier to live in while you are there. Keep the paperwork: the scope, the depths installed and any assessment report. If you finance through NYSERDA’s On-Bill Recovery Loan, the balance can transfer to a buyer with written notice; with a Smart Energy Loan, the seller stays responsible for it. Filling closed walls is harder to justify on a short timeline.
Free energy audit in Mastic
In a 1970s house we follow the ducts from the furnace, go up to the attic for the top plates, hatch and flue, then down to the rim joist and the garage ceiling. In an older small house we get into the crawl space and check where each addition joins the house. We check the oil burner’s air supply and flue before recommending any sealing, and if you would rather work in stages, we write the scope that way. There is 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 Mastic Beach
- Insulation in Shirley
- Insulation in Manorville
- Air sealing
- Attic insulation
- Crawl space insulation