Purchase has the biggest houses and the smallest sample on our Westchester
list. It is not a Census-defined place, so every figure below is for the
10577 ZIP code and its 883 housing units — enough to
describe the shape of the housing, not enough to quote to the decimal:
96.0% single-family detached, the highest share of any
geography we cover, median build year 1984.
The houses we insulate in Purchase
Owner occupancy comes back at 99.1%, but on a base of seven renter
households, so treat it as directional. The age distribution is bimodal:
22.3% went up in the 1980s and
15.2% still predates 1940, with 12.9% 1960s,
11.9% 1990s and 11.6% 2010s in between. Purchase sits inside the town of
Harrison, which has its own
page.
The 1980s-through-2000s houses are the work. They are large, often past 6,000
square feet of exterior envelope once the roof is counted, and complicated. Such
a house does not have an attic; it has three or four at different heights,
separated by knee walls and joined by dropped ceilings and chases, and the air
barrier stops at every junction. The air handler and duct trunk usually sit in
one of them, pressurized and on the wrong side of the insulation. The cathedral
great room almost always has batts jammed against the sheathing with no baffle
and no vent channel, and the bonus room over the three-car garage is cold
because its floor cavity is open at the band joist.
On a house this size the blower door is the whole sale. We test, find where
the leakage actually is — on a six-plane roof it is rarely where the owner
expects — then seal the plane transitions, baffle and re-insulate the
cathedral bays, close the bonus room floor, and either seal the ducts or bring
the attic holding them inside the envelope.
The 15.2% built before 1940 is the surviving estate stock and a different
building. Slate roofs make roof-deck foam economically silly once scaffolding
and a slater are added, so the work goes to the attic floor. Balloon-framed stud
bays get blocked and sealed at the top plate before anything is blown into a
wall.
We seal before we insulate
Insulation slows heat moving through a surface. It does nothing about air
moving through a gap. Pack a leaky attic with cellulose and you have a leaky
attic with cellulose in it — the air still moves, it just moves through
something softer.
In a Purchase house the holes are neither small nor few. Every place one
attic plane steps up to the next is a hole, and so is the duct chase, the
framing above a dropped soffit, the attic hatch, and thirty or forty recessed
cans. Then we insulate.
What insulation costs in Purchase
Most of our projects run between $3,500 and $12,500, and
Purchase houses land at the upper end more often than not. Not the square
footage: the number of attic planes, and the fact that air sealing a six-plane
roof is measured in days.
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 Purchase
Worth saying plainly here: the rebates are real, and on these houses they are
a contribution rather than a determinant. Do not let a $2,500 program shape the
scope of a 6,000 square foot envelope. Purchase is Con Edison
for gas and electricity, and Con Edison’s residential
Weather Ready program is not accepting
applications; its own page points Westchester customers to NYSERDA
until 2027 incentives are announced. Any $4,000 Con Edison figure still online
is stale.
The live program is NYSERDA Comfort Home:
$2,500 to air seal and insulate the attic and rim joist,
$3,000 with wall and floor insulation added,
$2,000 more toward ENERGY STAR windows afterwards. The
contractor must be on NYSERDA’s Comfort Home list and the house must meet the
conditions of the whole package. EmPower+ — no cost up to
$14,000 downstate at or below 80% of area median income, half
the cost up to $7,000 at moderate incomes — will not
apply here. See the full New York 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 Purchase
The median Purchase house went up in 1984, more than a fifth of the ZIP code
in that decade alone, so most of the housing here was built well short of
anything current. The current code is the 2025 Energy Conservation
Construction Code of New York State, in force since 31 December
2025, based on the 2024 IECC; Westchester is climate zone 4.
It sets R-49 in the ceiling, R-30 in
wood-framed walls (or R-20 cavity plus R-5 continuous, R-13 plus R-10
continuous, or R-20 continuous), R-30 in floors, and R-15
continuous, R-19 cavity or R-13 plus R-5 continuous in basement and crawl space
walls. Anyone quoting R-60 is quoting Connecticut. None of it applies to
a house already standing: the code does not require an existing
building to be altered, only that an alteration not leave you with less than you
had. ENERGY STAR recommends R-60 for a retrofit attic,
guidance rather than law.
Common questions about insulation in Purchase
Do you install insulation in Purchase, NY?
Yes. Purchase is 96% detached single-family and mostly large, so nearly
everything here involves several attic planes at different heights with
equipment living in one of them.
How much does insulation cost in Purchase?
Most projects run $3,500 to $12,500, and Purchase houses tend to sit high in
that range. The driver is roof geometry and access, not floor area: four attic
planes with a duct trunk to work around is days of air sealing.
Are there insulation rebates in Purchase?
Yes, through NYSERDA, though modest against a house this size. Con Edison’s
own weatherization program is not accepting applications, so Comfort Home is the
live one: $2,500 for air sealing plus attic and rim joist, $3,000 with walls and
floors. There is no federal tax credit on a 2026 job.
Only the bonus room over our garage is cold. Is that a whole-house job?
Usually not. That room typically has an open floor cavity at the band joist,
an uninsulated garage ceiling below it and knee walls with nothing on the back.
Closing those three is a contained job, though we will test the house first,
because the bonus room is sometimes only the symptom you notice.
Free energy audit in Purchase
We walk every attic plane, look at the air handler and duct runs, check the
cathedral bays, the bonus room floor and the basement, and give you a written
scope and a price. No charge, no obligation.
Call 914-825-6824 or use the form on this page. Open
8am–8pm, seven days. We have insulated hundreds of homes across New York,
Connecticut and New Jersey with a 100-plus in-house crew.