Closter is 91.3% detached houses, the highest share of the fifteen Bergen County towns we cover, and 38.8% of its homes went up in the 1940s and 50s. The median Closter house is a 1957 cape on a street where nearly every building is a single-family home.
The borough also holds nine Register-listed Jersey Dutch sandstone houses, the densest stone-house inventory on our list, and those we treat differently: solid stone has no cavity, and we will not drill it.
This page is for the cape owner first, then the Victorian, then the stone house.
The houses we insulate in Closter
The median Closter home was built in 1957. Of 2,723 units, 19.4% predate 1940, 38.8% went up in the 1940s and 50s, 20.7% in the 1960s and 70s, 13.5% in the 1980s and 90s and 7.6% since 2000; 79.0% predate 1980. Only 6.5% of units are in two- to four-family buildings and 82.0% are owner-occupied, so the person who calls us is almost always the person who signs.
The post-war streets are the volume. Closter grew from 1,057 people in 1900 to 7,767 in 1960, and most of that growth is capes and story-and-a-half houses. They fail the same way every time: knee walls with no air barrier on the back side, floor joist bays running open from the finished bedroom to the eave, 2×6 roof slopes stuffed with batts and no baffle, and a shallow flat attic nobody has entered since the house was framed. Many of these capes wear asbestos-cement shingle siding. We fill those walls from inside or by lifting shingles, never by drilling through the siding.
Next is the 1960s–70s fifth: ranches and splits with settled loose-fill in a long low attic, wind-washed eaves, cantilevered bays and a bedroom over the garage. Those houses have insulation; it has settled, and the bypasses under it were never sealed.
The 19.4% built before 1940 is the railroad layer. The Northern Branch reached Closter in 1859, and by 1865 the commute was 58 minutes, which earned the borough the name “Hub of the Northern Valley.” The Victorians around the station and in the West Street/Harrington Avenue Historic District, the borough’s one designated district, are balloon-framed: stud bays open from sill to attic, plank sheathing, no wall insulation, a rubble foundation with a leaky rim. We block the plates before we dense-pack, we check anything pre-1950 for knob-and-tube first, and vermiculite in a 1930s–50s attic flat stops the job until it has been tested.
The same cape sits in Cresskill, the same Victorian in Englewood. What Closter has that they do not is the stone.
Closter’s stone houses: what we will and will not do
Nine Closter houses are on the National Register as Early Stone Houses of Bergen County: De Clark, Abram Demaree, Haring–Auryanson, Nagle, Henry Naugle, Isaac Naugle, Tallman–Vanderbeck, Van Horn and Vervalen. They are native red sandstone, south-facing with long eaves. The Abram Demaree homestead, occupied by 1769 and given a Federal wing in 1809, is the pattern: a stone core and a later frame wing.
The stone walls are solid, with plaster on the stone or on shallow furring. There is no cavity to fill, and landmark status usually forbids exterior drilling anyway. What can be done: air seal and insulate the attic floor or the garret roof from inside, seal the rubble cellar and its wet rim, and dense-pack the frame wing, which is usually where most of the heat was going.
A 2004 survey counted more than 200 historic buildings in the borough, most altered at least once, and the borough’s own preservation plan names teardowns as the threat. One more Register listing: the 1950 Harold Hess Lustron House, a prefabricated porcelain-enameled-steel house, one of three built in Bergen County. Nothing on this page insulates a steel house, and we say so.
We seal before we insulate
Insulation slows heat moving through a surface. It does nothing about air moving through a gap. Blow cellulose over a leaky attic floor and you have a leaky attic floor with cellulose on it.
In a Closter cape the sequence is fixed. Block the joist bays where they pass under the knee wall so the eave cannot breathe into the bedroom floor, put a rigid air barrier on the back of the knee wall, baffle the slopes so the flat can vent, seal the top plates, the plumbing stack, the chimney chase and the bath fan, then insulate the knee wall, the slopes and the flat.
If a quote specifies a depth of insulation and never mentions air sealing, it is half a job.
What insulation costs in Closter
Most of our projects run between $3,500 and $12,500. In a Closter cape what moves the number is the run of knee wall and slope, how much of the flat attic is reachable, and whether the walls are filled from inside behind asbestos-cement siding. A stone house is priced on its garret, cellar and frame wing, because the stone is not touched.
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 Closter
Closter gets its electricity from Rockland Electric, the New Jersey arm of Orange & Rockland, and its gas from PSE&G.
Rockland Electric Whole Home Energy Solutions offers up to $7,500 in rebates plus interest-free financing, typically over seven to ten years. Every project must include at least attic air sealing and an attic insulation upgrade. The work must be done by a BPI-certified contractor participating in the program. Rockland Electric’s Home Energy Assessment is free for its residential customers.
Rockland Electric Home Weatherization covers insulation, air sealing and duct sealing at no cost for income-qualified households, roughly $39,900 to $63,840 for one person and more for larger households. Because the gas is PSE&G, PSE&G’s free Whole Home Energy Assessment also applies. Whether PSE&G’s rebate program accepts a PSE&G-gas, Rockland-Electric home is not stated on PSE&G’s page, so start with Rockland Electric’s program and confirm with PSE&G.
New Jersey Comfort Partners installs insulation and air sealing at no cost for households at or below 250% of the federal poverty guidelines, for example $82,500 for a family of four; homes heated with oil or propane are referred to the state weatherization office. The New Jersey IRA Home Energy Rebates have not launched — the state’s page says “under development” — so they are not available yet. See the full New York and New Jersey rebate guide.
The federal Section 25C tax credit ended for anything placed in service after 31 December 2025. There is no federal insulation credit on a 2026 job.
Code and climate in Closter
Nearly eight Closter units in ten, 79.0%, predate 1980, and New Jersey’s first statewide energy subcode took effect on 1 January 1977: most of the borough was built with no energy code. Bergen County is climate zone 5A; Essex, Hudson and Union next door are 4A.
New Jersey adopted the 2024 IECC on 17 August 2026. For new construction it sets R-49 ceilings — the 2021 edition it replaced called for R-60, and a permit application filed under the old code is still accepted for six months, until about mid-February 2027 — with walls at R-20 plus R-5 continuous, windows at U-0.28, and air leakage of 3.0 air changes per hour at 50 pascals. R-49 is the number the state considers right for this climate, and it is what we design to.
A 1957 cape falls under New Jersey’s Rehabilitation Subcode: insulating the attic does not require bringing the rest of the house to code or a blower-door test. Blown-in or batt insulation installed against the interior finish is ordinary maintenance with no permit; spray foam and other foam plastic insulation need a permit, which we pull as part of the job.
Common questions about insulation in Closter
Do you install insulation in Closter, NJ?
Yes. Most of the work here is post-war capes, 38.8% of the borough’s housing, then the 1960s–70s splits and the pre-1940 houses around the station. Closter is 91.3% detached and 82.0% owner-occupied, so the scope is usually one house and one decision-maker: knee walls, slopes and flat attic first, then the basement rim, then the walls.
How much does insulation cost in Closter?
Most projects run $3,500 to $12,500. In a cape the drivers are the length of knee wall and slope, how reachable the flat attic is, and whether the walls go in from inside behind asbestos-cement siding. A pre-1940 house with knob-and-tube adds an electrician’s cost ahead of ours. A stone house is priced on its garret, cellar and wing alone.
Are there insulation rebates in Closter?
Yes. Closter is Rockland Electric territory for electricity and PSE&G for gas. Rockland Electric Whole Home Energy Solutions offers up to $7,500 in rebates plus interest-free financing, typically over seven to ten years, and every project must include at least attic air sealing and an attic insulation upgrade. Its Home Energy Assessment is free. There is no federal insulation credit on a 2026 job.
We own one of Closter’s stone houses. What can you do without touching the stone?
Quite a lot, and none of it involves a drill. The sandstone walls are solid, so there is no cavity to fill, and landmark rules usually forbid exterior work in any case. We air seal and insulate the attic floor or the garret roof from inside, seal the rubble cellar and the rim, and dense-pack the later frame wing, which is usually where most of the heat was going.
Free energy audit in Closter
In a cape we walk the knee-wall spaces, the flat attic and the basement rim. In a Victorian we open the attic and check the wiring first. In a stone house we look at the garret, the cellar and the wing and leave the stone alone. Then a written scope and a price, no charge, no obligation. If the flat attic is fine and the real problem is the knee walls, we will say so.
Call 914-825-6824 or use the form on this page. Open 8am–8pm, seven days. We work out of New Rochelle, NY with a 100-plus in-house crew.
Learn more
- Insulation contractors across Bergen County
- New Jersey insulation rebates in full
- Types of insulation
- Open cell and closed cell spray foam compared
- Insulating an older home
- Attic insulation guide
- What happens during an energy audit