Attic Air Sealing Improves Energy Efficiency
If your attic has never been properly air sealed, this is your chance to fix it, and lower your energy bills.
Once the bypasses are sealed and verified with a blower door test, the results are measurable: 15–25% lower energy costs and comfort that actually lasts.
Serving the region
Since 2005
Quick Answer
Attic air sealing closes gaps and penetrations in the attic floor — called bypasses — that allow conditioned air to escape. The U.S. Department of Energy estimates these bypasses account for 25–40% of a home’s total heating and cooling loss. Professional sealing with two-part foam and fire-rated caulk can reduce energy costs by 15–25% annually.
Understanding the Problem
What Are Attic Bypasses — and Why Do They Matter?
Attic bypasses are gaps in the attic floor through which warm air escapes into the cold attic. Your heating system works overtime trying to replace that air — driving up energy bills without improving comfort.
Top Plates
Gaps at the top of interior walls where framing meets the attic floor — among the largest sources of air loss in most homes.
Plumbing Chases
Oversized holes cut for pipes and drains — often 4–6 inches wide with no seal around the pipe itself.
Recessed Lights
Every recessed can is a hole in the ceiling. Older models are neither airtight nor IC-rated, making them major thermal bypasses.
Chimney Chases
Large open cavities around masonry chimneys require intumescent (fire-rated) sealant — regular caulk is not safe here.
Electrical Penetrations
Wire runs through framing carry air from conditioned spaces into the attic — small but numerous in most homes.
Attic Hatches
Uninsulated pull-down stairs and hatches act like open windows — warm air escapes and cold attic air drops in.
Why Air Seal First
Why Sealing Your Attic Pays Off Year-Round
Air sealing is the highest-ROI energy improvement most homes can make — before adding a single inch of insulation. In summer, the same bypasses that bleed heat in winter pull hot, humid outdoor air into your home, forcing your AC to work harder and driving up cooling bills. Sealing them pays off in every season.
Lower Energy Bills
Most homeowners see 15–25% lower HVAC costs year-round — on both heating bills in winter and cooling bills in summer.
Even Comfort Room to Room
Hot upstairs rooms in summer, cold drafts in winter, and floors that never reach temperature are all air leakage symptoms. Sealing bypasses equalizes pressure and temperature throughout the home in every season.
Moisture & Mold Prevention
Warm humid air rising through bypasses condenses on cold attic surfaces. Over time this causes mold, wood rot, and structural damage.
Make Insulation Work
Insulation slows heat transfer but doesn’t stop airflow. Without air sealing, warm air bypasses insulation entirely. Seal first, then insulate.
Smaller HVAC Loads
When your home stops bleeding conditioned air, both your furnace and AC run in shorter, more efficient cycles — reducing wear and extending equipment life year-round.
NYSERDA Rebate Eligible (NY)
New York homeowners may receive NYSERDA rebates up to $500 on qualifying projects. Metro NY Insulation is an approved NYSERDA contractor.
Our Process
Our 5-Step Process: From Blower Door Baseline to Verified Results
Home Energy Audit & Blower Door Test
We pressurize the home to measure total air leakage (CFM50) and locate exactly where air is escaping. This baseline lets us verify measurable improvement after sealing.
Attic Inspection & Bypass Mapping
Our crew inspects the entire attic floor, cataloguing every bypass — top plates, plumbing chases, recessed lights, chimney chases, and electrical penetrations — before any work begins.
Sealing with Two-Part Foam & Fire-Rated Caulk
Each bypass is sealed with the right material: two-part spray foam for larger gaps, fire-rated caulk around light fixtures and wiring, and intumescent sealant at chimney chases.
Post-Seal Blower Door Verification
We re-test after sealing to verify measurable improvement — typically a 25–40% reduction in air changes per hour. You get the before/after numbers in writing.
Insulation Installation (Recommended)
With bypasses sealed, we can install or top-up cellulose to R-49 for the NJ/NY climate zone — maximizing the return on your air sealing investment.
Why the Blower Door Test Matters
Without a blower door test, air sealing is guesswork. We measure before and after every project so you know exactly how much improvement was achieved — not just what was sealed. It’s the only way to verify bypasses were fully closed.
What Homeowners Say
Expert Insulation Services In New Jersey & Westchester Since 2005
Read Our Reviews arrow_forward“The Metro NY Crew under Coswayne was amazing. The work was absolutely first rate and the customer service beyond expectation. When a few issues were found after the job, Metro NY sent a crew back to ensure that all loose ends were tied up. Throughout the process, the staff and crew were courteous and responsive to all needs. They also offer very fair pricing. I would highly recommend to anyone I know and would use again if/when needed.”
— Jonathan Jaffe, Google Review
“Jay was very responsive and communicative. He and his crew were super neat and very efficient doing the blow in insulation. We no longer have to worry about heat loss or even mice in our basement. Thanks for letting us know about the tax credit, too!”
— Adam Lefford, Google Review
“Jay Mosquera conducted my home’s evaluation. He was knowledgeable, honest and extremely professional in his recommendations. He explained clearly all steps of the project and made me feel at ease regarding the work to be performed. He is truly a valuable asset to your company.”
— Luisa Feliz, Google Review
Our Work
Real Projects: Attic Air Sealing
Recent work from New Jersey and Westchester County homes.
NJ & Westchester’s Trusted Bypass Sealing Contractor — Since 2005
We serve homeowners throughout northern New Jersey, Westchester, and the lower Hudson Valley. We know the housing stock, building codes, and energy program requirements in every county we serve.
Complete the Picture
Complete The Picture and Maximize The Results
Attic Insulation
Air sealing + blown-in cellulose to R-49 is the complete attic performance package for NJ/NY climate zone.
wall_artWall Insulation
Dense-pack cellulose for open exterior walls — no drywall removal. Eliminates cold walls and hot spots.
search_insightsHome Energy Audits
A full energy audit with blower door test shows exactly where you’re losing the most energy before we start.
Frequently Asked Questions
Ready to Seal Your Attic?
Schedule a targeted home energy evaluation — includes thermal imaging and a written scope of work with exact pricing. Learn about the difference between a targeted evaluation and a full audit →