Spray foam insulation seals air leaks and insulates in a single step. It is sprayed on as a liquid, expands to many times its size to fill the cavity, and hardens within seconds — closing the cracks and gaps that let heated and cooled air escape. That combination is why it outperforms batt insulation, which slows heat but lets air pass straight through.
The Home Insulators has installed spray foam in homes across Westchester, Rockland, and Bergen County since 2015, using our own crew rather than subcontractors. Most spray foam projects run $3,500 to $12,500. Call 914-825-6824 for a free energy audit.
What is spray foam insulation and how does it work?
Spray foam begins as two liquid components that are combined at the tip of a spray gun. The instant they mix, they react and expand — often many times their original volume — filling the cavity and hardening into place within seconds. That expansion is what sets foam apart from other insulation: instead of simply slowing heat like a blanket, it also seals the small cracks, gaps, and seams where conditioned air escapes and outdoor air sneaks in.
Because air leakage accounts for a large share of the heating and cooling loss in most homes, closing those pathways is often where the biggest comfort and efficiency gains come from. Combining air sealing and insulation in one product is a major reason many homeowners see 20% or more come off their monthly bills after the work is finished.
Closed-cell or open-cell foam — which one do I need?
Spray foam comes in two forms, and choosing between them is one of the most important decisions in any project.
- Closed-cell foam is dense and rigid, insulating at roughly R-6 to R-7 per inch (the products we install are rated at R-6.9 to R-7.1 per inch). Its tight cell structure makes it both an air barrier and a vapor barrier, so it resists moisture and even adds a measure of structural rigidity. It is the stronger choice for rim joists, crawl spaces, and anywhere moisture control matters.
- Open-cell foam is softer and lighter, insulating at about R-3.9 to R-4.2 per inch. It is more breathable, dampens sound well, and costs less, which makes it a smart fit for interior walls and large open cavities where extreme moisture resistance is not required.
For perspective, standard fiberglass batt insulation delivers roughly R-3 to R-4 per inch. So an inch of closed-cell foam can nearly double the insulating value of an inch of batt while also stopping the air movement that batts cannot.
Where should spray foam be used in a house?
Spray foam is not the right answer for every surface, but it excels in the places where air and moisture problems usually start:
- Attics and cathedral ceilings, where sealing the roofline creates a conditioned, temperature-stable space
- Rim joists and band boards, a notorious source of drafts along the top of the foundation
- Crawl spaces and basement walls, where closed-cell foam controls both cold and dampness
- Bonus rooms and additions over garages that never seem to hold temperature
In many homes we combine materials — foam where sealing matters most, and blown-in or fiberglass batt in open areas where it is more cost-effective. A sound insulation plan uses the right product in the right place, not one material everywhere.
What are the downsides of spray foam, and how long does it take?
Spray foam's advantages are real, and honest guidance means naming the trade-offs too. It costs more up front than batt or blown-in insulation, it must be installed by trained professionals with proper equipment and ventilation, and once it has cured it cannot simply be pulled out and repositioned like a batt. Installed correctly, though, it does not sag, settle, or lose performance over the years.
A typical installation is faster than most homeowners expect. Our crew protects the surrounding area, applies the foam in even layers, and trims any excess once it expands and sets. The material cures quickly, and we ventilate the space during and after the work. Most projects wrap up in a day or two, depending on size and scope.
Common questions about spray foam insulation
What is spray foam insulation?
Spray foam insulation is a material that air-seals and insulates at the same time. Two liquid components combine at the spray gun, react, expand to fill the cavity, and harden in seconds. Unlike batt insulation, which only slows heat transfer, spray foam also blocks the air movement that carries most of a home's energy loss.
What is the difference between closed-cell and open-cell spray foam?
Closed-cell foam is dense and rigid and insulates at roughly R-6 to R-7 per inch — the products we install are rated at R-6.9 to R-7.1. It acts as both an air barrier and a vapor barrier, resists moisture, and adds some structural rigidity, which makes it the better choice for rim joists, crawl spaces, and anywhere moisture matters. Open-cell foam is softer and lighter at about R-3.9 to R-4.2 per inch, breathes more, dampens sound well, and costs less — a good fit for interior walls and large open cavities.
Is spray foam better than fiberglass batt insulation?
For sealing, yes. Fiberglass batt delivers roughly R-3 to R-4 per inch, so an inch of closed-cell foam can nearly double that — and batt does almost nothing to stop air movement, because it filters air rather than blocking it. Batt is still the more cost-effective choice in open areas where sealing is not the issue. Most of the homes we work on use both, with foam where sealing matters most.
Where should spray foam be installed in a house?
Attics and cathedral ceilings, where sealing the roofline creates a temperature-stable space; rim joists and band boards, a common source of drafts along the top of the foundation; crawl spaces and basement walls, where closed-cell foam handles both cold and dampness; and bonus rooms or additions over garages that never hold temperature.
What are the downsides of spray foam insulation?
It costs more up front than batt or blown-in. It has to be installed by trained professionals with the right equipment and ventilation. And once it cures it cannot be pulled out and repositioned the way a batt can. Installed correctly, it does not sag, settle, or lose performance over time.
How long does spray foam installation take?
Most projects are finished in a day or two, depending on size and scope. Our crew protects the surrounding area, applies the foam in even layers, trims the excess once it expands, and ventilates the space during and after the work.
How much can spray foam insulation cut my energy bills?
Many of our customers see 20% or more come off their monthly bills after the work is done. Air leakage accounts for a large share of heating and cooling loss in most homes, so closing those paths is usually where the biggest gains come from. The actual figure depends on the house, which is what the free energy audit is for.
How much does spray foam insulation cost?
Most of our spray foam projects run between $3,500 and $12,500. Where a job lands in that range depends on the size of the area, whether it is closed-cell or open-cell, how accessible the space is, and how much preparation the existing insulation needs. A free energy audit gives you a firm number for your house rather than a range — we measure the space and quote from that, not from a square-foot guess over the phone.
Do you serve my area?
We work across Connecticut, the Hudson Valley, and all of New Jersey, with most projects in Westchester, Rockland, and Bergen County. Call 914-825-6824 to check your address.
Towns where we install spray foam
Westchester County, NY — Armonk, Bedford, Briarcliff Manor, Bronxville, Chappaqua, Cortlandt, Eastchester, Greenburgh, Harrison, Hartsdale, Irvington, Larchmont, Lewisboro, Mamaroneck, Mount Kisco, Mount Pleasant, Mount Vernon, New Castle, New Rochelle, North Castle, North Salem, Ossining, Peekskill, Pelham, Port Chester, Pound Ridge, Purchase, Rye, Scarsdale, Somers, Tarrytown, Tuckahoe, Valhalla, Westchester County, White Plains, Yonkers, Yorktown.
Rockland County, NY — Clarkstown, Haverstraw, Nanuet, Nyack, Pearl River, Ramapo, Rockland County.
Bergen County, NJ — Closter, Cresskill, Englewood, Fort Lee, Hackensack, Leonia, Mahwah, Montvale, New Hillsdale, Norwood, Palisades Park, Paramus, Ramsey, Ridgefield, Rutherford.
We also work across Fairfield County, Connecticut, and the wider Hudson Valley. If your town is not on the list, call 914-825-6824 — we very likely still cover it.
Not sure whether spray foam, blown-in, or a combination is right for your home? That is exactly what our free energy audit is for — we will inspect your insulation, find where your home is losing energy, and recommend only what really pays off. Call The Home Insulators at 914-825-6824 to schedule your free audit and start lowering your bills.