Attic Insulation and Air Sealing on Long Island

Blown-in attic insulation runs roughly $1.00 to $2.80 per square foot installed depending on material, depth, and how much prep the attic needs. A typical 1,200 square foot Long Island attic lands somewhere around $1,700 to $3,400 before rebates. Older homes usually need air sealing first, and homes with damaged, wet, or rodent-contaminated insulation need the old material removed, both of which add to the job. We give you a written number after we have actually been in the attic, not over the phone.

PSEG Long Island runs a Home Performance program that pays up to $2,500 toward insulation and up to $1,000 toward air sealing, with the full envelope package capped at $4,000 for market rate households. Households in a Disadvantaged Community or at moderate income can qualify for $5,000, and income-qualified households can qualify for $8,000. Your tier depends on income and address and PSEG verifies it, so we do not promise an amount until they confirm it in writing.

Because insulation slows heat moving through a surface, but it does nothing about air moving around it. If your attic has open wall cavities, gaps around recessed lights, an unsealed attic hatch, and leaky top plates, warm air escapes straight through the new insulation you just paid for. PSEG requires blower-door-assisted air sealing alongside insulation for exactly this reason. It is also the part most homeowners have never had done, and it is usually the bigger comfort improvement of the two.

A few reliable signs: you can see the tops of the ceiling joists when you look across the attic floor, which usually means you are under R-19 and should be near R-38 or better. Rooms over the garage or on the second floor run cold in winter and hot in summer. Ice dams form on the roof edge. Your heating bill is out of line with your neighbors. The only way to actually know is to measure the existing depth and check for gaps, which is what the assessment is for.

For most Long Island attics, blown-in cellulose or fiberglass. It fills irregular spaces and gets into the corners and around obstructions the way batts cannot, and it covers far more attic per dollar than foam. Spray foam has its place, usually at a roof deck or a rim joist, and we can spec it when a job genuinely calls for it. But on a fixed rebate, the cheaper material per R-value covers more of your attic and more of your project cost, so blown-in is what makes sense for most homes.

Usually no. Most of the time new blown-in goes right on top of what is already there, as long as the existing material is dry, uncontaminated, and evenly distributed. Removal becomes necessary when insulation is wet, moldy, has rodent contamination, or is old vermiculite. We tell you which situation you are in during the assessment, and removal is quoted separately so you can see exactly what it costs.

Most attics are a one-day job. Air sealing takes the first several hours, then blowing in the insulation takes a few more. Larger homes, jobs that need old material removed first, or attics with difficult access can run into a second day. We tell you which one yours is before we start.

Before, or at the same time, if you can. A tighter, better insulated house needs a smaller heat pump, and a smaller heat pump costs less to buy and less to run. If we size a system for a leaky house and you insulate the following year, you have paid for capacity you no longer need. When both are on the table we sequence the envelope work first and then size the equipment to the house you will actually have.