More than a third of the hamlet of Riverhead has been built since 2000. 27.8% of its 5,463 homes, 1,518 of them, date from the 2000s alone, another 6.8% from the 2010s and 2.0% from 2020 or later, for 36.6% in all, and the median home was built in 1988. Yet 12.1%, 663 homes, predate 1940.
The housing is mixed in form as well as age. 55.5% of homes are detached houses and 17.2% are attached, with 6.2% in three- and four-unit buildings, 5.9% in buildings of five to nine, and 7.3%, 399 homes, in mobile homes. 60.7% of occupied homes are owner-occupied. Utility gas heats 47.6% of occupied homes, fuel oil 34.4%, electricity 12.0% and bottled gas 4.7%.
A note on the name. These figures cover the hamlet of Riverhead, not the much larger Town of Riverhead that contains it and other hamlets, among them Wading River, which has its own page. The hamlet sits at the mouth of the Peconic River, where it empties into Peconic Bay at the split between the North and South Forks, and it holds the principal downtown of the Town and the seat of Suffolk County. Beyond downtown it runs out into rural sections with active farms and residential developments.
The houses we insulate in Riverhead
The 663 homes from before 1940 date from the long stretch when Riverhead was the county seat and a 19th-century commercial hub, and from the early 20th century, when Polish immigrants settled here and Polish Town took shape. Houses of that age get treated as balloon-framed, their stud bays running unbroken from cellar to attic, and as wired with knob-and-tube, until an inspection says otherwise; live old wiring is replaced before any wall is filled. Their attics may be small and steep, their cellars may have stone or brick walls, and porches that were closed in as rooms have no insulation in their floors or low roofs.
The 1940s added 349 homes and the 1950s 668, mostly capes and small ranches. The cape leaks at the knee walls, with nothing on their attic side, and at the floor joists that run open under them to the eave. The ranch leaks overhead, through settled loose-fill and a ceiling full of unsealed holes. The 1960s added 324 and the 1970s 419, raised ranches and splits with bare rim joists and garages under bedrooms.
The 1980s added 372 homes and the 1990s 670, and then the 2000s built 1,518, the largest decade in the hamlet by far. Alongside them stand the 942 attached homes, townhouses in rows that share party walls and often a continuous roof, and the detached houses of that era are typically colonials. They are the subject of the next section.
The 341 units in three- and four-unit buildings we scope as whole buildings, since the attic and cellar are shared. The buildings of five units and more are managed by their owners. The 399 mobile homes are a limited job, and the last question below explains what can and cannot be done.
Built since 2000: 36.6% of the hamlet, and where a newer house still leaks
A Riverhead house or townhouse from the 2000s was built with full walls and an insulated attic under the energy code of its day, and nobody should sell its owner a wall job. But “built to code” and “sealed” are different things, and the newer houses leak in predictable places.
The attic holds the air handler. Many houses of this era put the furnace or air handler and its ductwork in the vented attic, outside the insulation. Every duct joint that leaks pushes heated or cooled air into the attic, and the ducts themselves sit in a space that is freezing in January and far above outdoor temperature in July. Sealing the ducts with mastic and burying or wrapping them does more here than more insulation on the attic floor.
The ceiling is full of holes. Recessed lights in the top-floor ceiling, bath fans, a pull-down stair or hatch, and the chase where the ducts and flue rise all open into the attic. Each gets sealed, and any bath fan that vents into the attic gets a duct to the outside.
The townhouse has a party wall. In a row of attached homes, the fire-rated wall between units is meant to run to the roof deck, but gaps where it meets the roof, the exterior walls and the floor let air move between attics and into the unit. The end unit adds a full exterior side wall that the middle units do not have, which is why an end unit often costs more to heat and cool than its neighbors.
The garage is under or beside a room. A bonus room over a garage, or a bedroom beside one, sits over open joist bays or against a wall that was insulated but never sealed. The garage ceiling and the rim above the garage door are where that room loses its heat.
In an attached home, check the association’s documents before any work: the roof, the attic above the ceiling and the exterior walls may belong to the association, not the owner.
We seal before we insulate
Insulation slows heat moving through a surface. It does nothing about air moving through a gap, and in a newer house the gaps are concentrated overhead, where warm air rises into an attic that also holds the ducts.
In a 2000s Riverhead townhouse or colonial the order is: seal the duct joints and the air handler cabinet with mastic; seal the recessed lights, the bath fan housings, the hatch or stair and the duct and flue chase; close the gaps along the party wall where it meets the roof and the attic floor; seal the top plates. Then add insulation over the attic floor and around the ducts. Then the garage ceiling and the rim over the garage door. In an older house the sequence starts at the knee walls or the cellar rim instead, but the rule is the same.
If a quote specifies a depth of insulation and never mentions air sealing, it is half a job.
What insulation costs in Riverhead
Most of our projects run between $3,500 and $12,500. A townhouse from the 2000s, with one attic, ducts to seal and a garage ceiling, usually sits toward the lower end. A detached colonial of the same era is priced on duct footage, ceiling area and any bonus room. The top of the range belongs to pre-1940 houses whose balloon-framed walls need blocking and filling, and to three- and four-unit buildings priced as a whole. Foam pricing is covered in what spray foam costs.
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 Riverhead
Electricity in the hamlet of Riverhead comes from PSEG Long Island. Gas comes from National Grid, which serves many streets but not every one, so the bill settles whether yours is on a main. Because PSEG Long Island is the electric company, NYSERDA’s Comfort Home program is not available to Riverhead homes.
PSEG Long Island offers a free Whole House Energy Assessment, with a check of insulation and drafts, a thermal scan and a blower door test, and 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. Its rules require insulation to be installed with blower-door-assisted air sealing and all ductwork in unconditioned space to be duct sealed, which fits the newer houses here well. The rebates are paid through PSEG Long Island’s participating contractors, so ask the installer whether they are on that list. The list is written for single-family homes; owners of attached homes and mobile homes should ask PSEG Long Island whether theirs qualifies.
On the gas side, National Grid has stopped accepting new applications to its Long Island insulation rebate program. Households with qualifying incomes use EmPower+ instead, which serves owners and renters of one- to four-family homes. 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 Suffolk household of four) or half the cost up to $7,000 for moderate-income households (below $131,900 for four), through an EmPower+ contractor. Long Island households should check eligibility on the MyEnergy portal. NYSERDA’s Green Jobs–Green New York program also lends $1,500 to $25,000, unsecured, over 5, 10 or 15 years.
Section 25C, the federal insulation tax credit, ended for work placed in service after 31 December 2025, so there is nothing federal to claim on a 2026 job, and New York has no state tax credit for insulation. Each program is laid out in our New York and New Jersey rebate guide.
Code and climate in Riverhead
44.4% of the hamlet’s homes were built before 1980. New York’s first statewide energy code took effect on 1 January 1979. The houses built since 2000 went up under later editions of that code. Suffolk County, East End included, 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. Ceilings need R-49, though R-38 counts where it covers the whole ceiling and keeps its full uncompressed height above the wall top plate at the eaves. Floors need R-30. Basement and crawl space walls take R-15 continuous, R-19, or R-13 plus R-5 continuous. An unheated slab gets R-10 continuous insulation four feet in from its edge, windows must reach U-0.27, and the finished house must test at 3.0 air changes per hour at 50 pascals or less.
That table is not applied retroactively: unaltered portions of an existing house do not have to comply, and insulating an existing Riverhead home does not trigger a blower door test under New York’s code. If a renovation opens roof or wall cavities, though, whatever is exposed has to be filled to full depth. For attics, ENERGY STAR’s recommendation in this zone is R-60 when the attic is bare and R-49 when 3 to 4 inches are already there.
Common questions about insulation in Riverhead
Do you install insulation in Riverhead, NY?
Yes, in the hamlet of Riverhead and across the Town. In the hamlet most of our work is the 1,518 homes of the 2000s and the attached homes among them: ducts in the attic, ceilings full of recessed lights, party walls and garage ceilings. We also work on the pre-1940 houses from downtown’s older era, with balloon framing and old wiring checked first, the 1950s capes and ranches, and three- and four-unit buildings scoped as one. Mobile homes are a limited job.
How much does insulation cost in Riverhead?
Most projects run $3,500 to $12,500. A 2000s townhouse with one attic, ducts and a garage ceiling usually sits toward the lower end. A detached house of the same age is priced on duct footage, ceiling area and any bonus room, not walls. Pre-1940 houses with balloon-framed walls, and small multi-unit buildings priced as a whole, cost more. The written scope and price come after a free walk-through.
Are there insulation rebates in Riverhead?
Yes. The hamlet’s electricity comes from PSEG Long Island, which lists a $2,500 insulation rebate, a $1,000 air-sealing rebate and $500 for duct sealing for market-rate single-family homes and more for income-qualified ones, paid out through its participating contractors once a free Whole House Energy Assessment is done. Comfort Home is not open to PSEG Long Island customers. EmPower+ serves income-eligible owners and renters. No federal 25C credit applies to work placed in service after 31 December 2025, and New York offers no state insulation credit.
We own a mobile home in Riverhead. Can it be insulated?
Partly. The floor is usually the useful part: under the home, a fabric or board belly holds the floor insulation and often the main heating duct, and when it is torn the insulation falls out and the duct leaks into the open air. Repairing the belly, sealing the duct and refilling the floor cavity can make a real difference. The roof cavity is shallow and usually cannot be reached without opening the ceiling. Before we visit, we ask about the belly and the ducts, and we tell you plainly if the job is too small to be worth it.
Free energy audit in Riverhead
In a newer house we spend most of the time in the attic: the air handler, the duct joints, the recessed lights and fans, and along a townhouse’s party wall. Then the garage ceiling and the room above it. In an older house we start at the knee walls or the attic and finish at the cellar rim, checking for balloon framing and old wiring. If the insulation is fine and the job is the ducts, we say so. Then a written scope and a price. No charge, no obligation.
Call 914-825-6824 or send a message through our contact page. 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 Wading River
- Insulation in Manorville
- Air sealing
- Attic insulation
- Insulating a garage ceiling
- What happens during an energy audit