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New York Energy Resource Bureau
An independent homeowner guide to NY energy incentives
Source quality: Secondary

Insulation and Air Sealing: A NY Homeowner's Buyer's Guide

Equipment type: Building envelope (insulation and air sealing) Last reviewed: May 27, 2026 Source quality: Secondary

What this equipment is

Insulation and air sealing are two different jobs that get bundled together because they share a contractor and a workflow. Air sealing closes the holes in your house: gaps around plumbing penetrations, the cracks where the top plate meets the drywall, the bypasses around recessed can lights, the rim joist where the foundation meets the wood framing. Insulation slows the heat that moves through the closed surfaces themselves: attic floor, wall cavities, basement walls, crawlspace ceilings. Doing one without the other wastes money. Insulation laid over a leaky attic floor lets warm interior air pass right through it, and that moist air condenses inside the insulation and reduces its effective R-value over time.

For most New York homes, this is the cheapest energy work you can do per dollar saved. A typical pre-1980 wood-frame house in upstate NY leaks something on the order of 8 to 12 air changes per hour at 50 pascals (the blower-door test pressure). Tightening that envelope to 4 to 6 ACH50 cuts heating load before you touch the heating system. The payback on attic air sealing alone is often under five years.

Air sealing and insulation also set up everything else. A heat pump install on a leaky house is a bigger, more expensive heat pump that runs harder. Solar generation on an inefficient house powers a furnace that should not be running as much as it is. The envelope is the foundation.

Programs that apply

Most envelope work in New York is funded through one of a small set of state programs. The right one depends on your income and your utility.

  • Comfort Home Program. NYSERDA's flat-rate package program for insulation, air sealing, and (as an add-on) windows. This is the dominant funding source for envelope work in NY. The Good Package covers attic air sealing and rim joist insulation; the Better Package adds wall and floor insulation.
  • EmPower+. Income-qualified households can get insulation and air sealing at no cost through this program. If your household is at or below the cutoff, start here rather than Comfort Home. The two do not stack on the same scope of work.
  • Green Jobs-Green New York. The feeder program for home energy audits. The audit identifies which envelope problems matter and is the gate to most of the rebates above.
  • NYS Clean Heat. Not an envelope program, but relevant because envelope work is the prerequisite to a correctly-sized heat pump. The Manual J calculation on a tight house is smaller than the same calculation on a leaky one, and the heat pump that follows is smaller and cheaper.
  • NYSERDA Residential Financing. Low-rate financing if the rebate amount does not cover the full project.
  • Your utility's residential rebate page. Most NY utilities run their own weatherization rebates on top of Comfort Home. Con Edison customers in Westchester County often stack Comfort Home with Con Edison Residential Rebates on the same job.
  • Federal §25C Energy Efficient Home Improvement Credit. Expired December 31, 2025. See Federal Residential Energy Credits: Program Ended. Envelope work in 2026 does not qualify for the federal credit.

Sequencing your project

The order of operations is fixed, and skipping a step is one of the most common reasons homeowners end up with insulation that fails inspection or rebates that get denied.

  1. Blower-door audit first. A home energy audit through Green Jobs-Green New York is usually free or low-cost and produces a blower-door reading, an infrared scan, and a written list of recommended measures. Without that document, no contractor can defend a Better Package recommendation and no rebate program will pay out.
  2. Air-seal before insulating. This is the rule that gets broken the most. Air-sealing the attic floor, the rim joist, plumbing and electrical penetrations, and the can lights is cheap relative to insulation and has a larger effect on comfort and bills. Once insulation is in place, the air-sealing access is gone.
  3. Insulate to climate-zone targets. Most of New York is in IECC climate zone 5; the Adirondacks, Tug Hill, and parts of the North Country are in zone 6. Attic target is R-49 for both zones. Walls run R-13 to R-21 depending on stud cavity depth (2x4 vs 2x6 framing). Basement walls run R-15 to R-19, and rim joists should be air-sealed and insulated as a single step.
  4. Basement or crawlspace last. Conditioned basements should have the walls insulated rather than the ceiling above. Vented crawlspaces are usually best converted to sealed, insulated crawlspaces, but that decision depends on moisture conditions and should come from the auditor, not the contractor selling the work.
  5. Post-retrofit blower-door test. The participating contractor should run a second blower-door test after the work is done. The before-and-after numbers are what the rebate program pays against.

What to look for in equipment

You are not buying a box, you are buying installed performance. The materials matter less than the install quality, but specs still apply.

  • Blown-in cellulose is the workhorse for attic floors and dense-pack wall cavities in NY. R-value around R-3.5 per inch, made largely from recycled paper with borate fire and pest treatment. Settled density matters; the contractor should weigh the bags installed against the square footage and depth.
  • Closed-cell spray polyurethane foam has the highest R-value per inch (R-6 to R-7) and is also an air barrier. Reasonable for rim joists, basement walls, and tight retrofit cavities. Higher cost and a real environmental footprint from the blowing agents (look for HFO-blown foam over older HFC formulations).
  • Open-cell spray foam is lower R-value per inch (around R-3.7) and not an air barrier on its own at typical thicknesses. Avoid in unvented attic assemblies unless the contractor knows the code path.
  • Fiberglass batts still have a place in new framing and accessible cavities. In retrofits they tend to be installed poorly (compressed, gapped, voided), which destroys their rated R-value.
  • Rigid foam board (polyiso, XPS, EPS) on basement walls and exterior continuous insulation. Polyiso has the highest R per inch but loses some performance below freezing.
  • Air-sealing materials. Caulk and one-component foam for small gaps, two-component foam for rim joists, fire-rated caulk around flue penetrations, gasketed can-light covers for recessed lights bypassing the attic.

What to ask your contractor

  • Are you a NYSERDA-participating Comfort Home contractor, and which package are you bidding?
  • What was the blower-door reading before any work, and what is your target after the work?
  • How will you air-seal the can lights, plumbing chases, and the top-plate-to-drywall joint before insulating?
  • Are you blowing cellulose to settled density, and how will you verify the depth across the attic?
  • For dense-pack walls, what density (in pounds per cubic foot) are you targeting, and how do you confirm cavities are full?
  • Will you insulate and air-seal the rim joist in a single step?
  • For basement or crawlspace work, did the auditor specify wall insulation or ceiling insulation, and why?
  • Will you run a post-retrofit blower-door test and give me the number in writing?

Common pitfalls

  • Insulating without air-sealing. New insulation laid over a leaky attic floor traps moist interior air, reduces effective R-value, and accelerates wood rot at the sheathing. This is the single most common failure in retrofit envelope work.
  • Can-light bypasses left open. Older recessed cans are direct air leaks from conditioned space into the attic. Gasketed can-light covers (or replacement with IC-rated airtight LED retrofits) handle this. Many contractors blow insulation over uncovered cans and call the job done.
  • Knee-wall neglect. Cape Cods and finished-attic ranches have triangular knee-wall spaces behind the sloped ceilings. The vertical wall, the floor cavity behind it, and the back side of the knee wall all need to be air-sealed and insulated, in that order. Crews routinely skip the floor cavity.
  • Compressed batts. A 2x4 cavity stuffed with an R-15 batt that should have been an R-13 performs worse than the R-13 would have. Compression reduces R-value.
  • Wrong call on basement vs. crawlspace ceiling. Insulating a crawlspace ceiling and leaving the walls uninsulated keeps the crawlspace at outdoor temperature, which freezes plumbing and rots floor joists. The right call is almost always to insulate the walls and seal the crawlspace.
  • Contractor cuts corners on attic-floor air-sealing. Air-sealing is slow, dirty work. Insulation is fast. A contractor paid by the bag has an incentive to skip the air-sealing step. Insist on the air-sealing scope being itemized and inspected before insulation is blown.
  • No post-retrofit test. Without an after-number, there is no proof of work. The rebate program may pay regardless, but the homeowner has no documentation if the job underperformed.

Source

NYSERB.com is an independent research site. It is not affiliated with NYSERDA, the State of New York, or any utility. Verify all program details and incentive amounts directly with NYSERDA before making any financial decision.

Verified against www.nyserda.ny.gov, www.energystar.gov, www.energy.gov on May 27, 2026.

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