Spray Foam Insulation in Yonkers, NY

Spray foam insulation in Yonkers usually goes into a house that was built long before anyone thought about air sealing. Census survey figures for 2019 to 2023 put the median year built for Yonkers housing at 1958, with about 26.6% of units dating from before 1940. Those houses leak at the attic floor, the kneewalls, the rim joist and every chase that runs from the basement to the roof. We find those leaks, seal them, and insulate with open-cell or closed-cell spray foam where it earns its cost, or with blown-in cellulose or fiberglass where that does the job for less.

Why houses here lose heat

Yonkers spreads across hills that climb from the Hudson to 416 feet at the top of the city, and it has long been called the City of Seven Hills. Houses on those slopes take the wind, and many were built with balloon framing, open stud bays and attics that were never sealed from the rooms below. Warm air rises out of the living space all winter and pulls cold air in at the bottom of the house, usually along the sill plate and rim joist. In summer the same leaky attic floor lets heat pour down into the top bedrooms. Adding insulation without sealing those paths first leaves most of the problem in place.

The Westchester County Airport climate normals for 1991 to 2020, listed on Wikipedia's White Plains page, show what that means in numbers: a January daily mean of 29.8F, average January lows of 22.4F, average July highs of 83.2F, about 27.7 inches of snow and 47.75 inches of precipitation a year. A house here has to handle both a heating season and a humid cooling season.

What the state code asks for

Yonkers is outside the five boroughs, so New York City's own energy code does not apply here; the Energy Conservation Construction Code of New York State does. The county table in the code places Westchester in Climate Zone 4. The 2025 state code, based on the 2024 IECC and mandatory as of December 31, 2025 according to the Insulation Institute's summary, keeps ceilings at R-49 and tightens most other parts of the envelope. Code levels apply to new work, additions and renovations that open the structure, and your building department has the final word on any permit. For an existing attic, R-49 is a sensible target whether or not a permit is involved.

Closed cell vs open cell

Open-cell foam is soft and light, expands to fill odd cavities and stops air well, but lets some water vapor pass. HomeGuide lists it at R-3.5 to R-3.7 per inch. Closed-cell foam is dense and rigid at R-5 to R-7 per inch, slows vapor at typical thickness and does not soak up water. Around Yonkers we use closed-cell most often on rim joists, foundation walls, garage ceilings under bedrooms and roof slopes too shallow for vent channels. Open-cell fits roof lines over finished attics and walls that are open during a renovation. On an open attic floor, sealing plus deep blown-in insulation usually costs less and works just as well.

Spray foam insulation cost

HomeGuide puts installed spray foam at $1.50 to $5.00 per square foot, with open-cell at $1.50 to $3.50 and closed-cell at $3.00 to $5.00. About 1,000 square feet runs $1,500 to $5,000 by HomeGuide's numbers, and Fixr puts the same area in an existing home at $3,150 to $7,500. Whole-house projects run $8,000 to $20,000 on HomeGuide and $10,000 to $30,000 on Fixr. Prewar houses with plaster walls, tight attics and steep stairs tend to land toward the upper end because access takes time. The written estimate we give you after the visit is what you pay.

Rebates worth checking

Con Edison's Weather Ready weatherization program says it is no longer taking applications and points Westchester customers to NYSERDA's Comfort Home program. NYSERDA lists Comfort Home packages of $2,500 for sealing and insulating the attic and rim joist and $3,000 when walls and floors are added, plus an extra $1,000 for Westchester homeowners who are not eligible for Weather Ready. Sustainable Westchester notes that utility and state incentives require a participating installer, so check that before you sign with anyone, including us.

Choosing among spray foam insulation companies

When you compare spray foam insulation contractors near you, or any insulation contractors, ask each one the same questions. Which foam goes where, and how thick? What R-value will each area reach? What gets sealed before the insulation goes in? How long does the house need to be empty after spraying? Is old insulation coming out, and who hauls it away? A written answer to each of those is worth more than a low number on the phone. Get a free estimate

We work across Yonkers, from Getty Square and Park Hill to Crestwood, Dunwoodie and Nepera Park, and in the towns around it: Mount Vernon, New Rochelle, Pelham, Eastchester, Tuckahoe, Bronxville, Scarsdale, White Plains, Hastings-on-Hudson, Dobbs Ferry, Ardsley, Irvington, Tarrytown, Larchmont and Mamaroneck. The housing changes from place to place. Bronxville and Pelham are mostly prewar, with medians built in 1938. Tuckahoe's median is 1980 thanks to newer apartment buildings. The Sound shore villages deal with flooding, and the river villages sit on steep hillsides. Each town page below covers what is specific to that place.