Top-Rated Insulation Installers in Islip, NY

5 local companies ranked by 732 Google reviews. Free to compare, no sign-up.

Ratings collected September 2026 · Page updated September 30, 2026

5Companies
732Google reviews
4.7★Average rating
Sep 2026Data collected
Ranked by Google reviewsNever paid forFree to compare

Short answer: The top-rated insulation installers in Islip are Zavza Seal LLC (4.9★, 120 reviews), Rocket Insulation (5.0★, 19 reviews), Infinity Attic (4.7★, 58 reviews).

Insulation installers in Islip, ranked 5 listed

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  1. 1
    Zavza Seal LLCTop pickHighest rating (50+ reviews)
    4.9 (120 Google reviews)
    80 Orville Dr Ste 100, Bohemia, NY 11716
    Call (631) 980-1800WebsiteGoogle reviewsDirectionsEmail [email protected]
  2. 2
    Rocket InsulationTop pick
    5.0 (19 Google reviews)
    40 Haynes Ct, Ronkonkoma, NY 11779
    Call (631) 750-9075WebsiteGoogle reviewsDirections
  3. 3
    Infinity AtticTop pick
    4.7 (58 Google reviews)
    470 Suffolk Ave, Brentwood, NY 11717
    Call (631) 502-3786WebsiteGoogle reviewsDirections
  4. 4
    Green Team LIMost reviews
    4.6 (406 Google reviews)
    332B Dante Ct, Holbrook, NY 11741
    Call (631) 676-4717WebsiteGoogle reviewsDirections
  5. 5
    Home Efficiency Experts
    4.6 (129 Google reviews)
    1593 D, Locust Ave, Bohemia, NY 11716
    Call (631) 406-9805WebsiteGoogle reviewsDirectionsEmail [email protected]

Together these 5 companies average 4.7★ across 732 reviews. Green Team LI has the most reviews (406).

Ranked by Google rating weighted by review count, collected September 2026. Rankings are never paid for. How we rank and how we make money.

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What a insulation costs in Islip

Typical installed priceVaries by area

Price depends on which areas you insulate (attic, walls, basement) and how much air sealing is needed. Ask each company for a price per area and the R-value you end up with, so quotes are easy to compare.

Insulation rebates open in Islipup to $6,250

That could cut your cost by up to $6,250 if you qualify. Most rebates have rules (income, your current heating, a registered contractor, approval before work starts).

Rebates: our verified program data, checked monthly. Always confirm the exact amount for your home.

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Why insulation matters in Islip

In Islip, the average January low is -2°C (29°F), colder than 31% of the 123 cities we track. Winters here are mild, so comfort and summer heat matter as much as heating bills. Air sealing and attic insulation still help most, and they also keep upstairs rooms cooler in summer.

Most rebate programs pay only after an energy assessment, and some need one before the work too. Book it first.

Source: Open-Meteo historical weather data, 2015-2024.

Before you hire a insulation installer

  1. Ask whether they will air-seal before insulating, and what they will seal (attic hatch, pot lights, pipes, top plates).
  2. Ask for the R-value before and after for each area, and the material and depth they will install.
  3. Ask whether your rebate needs an energy assessment before and after the work, and who books it.
  4. Ask how they handle ventilation and any old insulation that could contain vermiculite (asbestos risk).

Before you call anyone, check what insulation rebates you can get in Islip. Many programs require approval or a registered contractor before work starts.

Planning more upgrades? See the top-rated heat pump installers, solar installers, home battery installers in Islip.

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