Air Sealing & Duct Sealing
Stop the air you already paid to heat.
Measured before and after.
Air leaks through the attic plane and rim joist, and duct leaks in the basement and attic, waste heating and cooling before it reaches the room. EnergiSense seals both, then proves it with a blower door and duct-leakage test.
- Attic plane + rim joist
- Duct leakage test
- Before-and-after numbers
- First step before insulation
Sealing service
Find the leak.
Seal it. Prove it.
Where most air leaves the house
Top plates, chases, recessed lights, hatches, and penetrations are sealed before insulation covers them.
Reclaim heat pump and AC output
Leaky ducts in unconditioned attics and basements dump conditioned air where it does nothing.
Numbers, not opinions
Blower door and duct-leakage results are recorded so the improvement is documented.
Sealing decision
Shell first, ducts second.
Insulation after both.
Sealing is the cheapest measure with the fastest return, and everything else on the plan depends on it being done first and measured.
01
Problem check
A house that feels drafty and a system that never seems to keep up are usually the same problem: uncontrolled air movement through the shell and the ducts. EnergiSense starts with the existing system, roof condition, utility account, and timeline so the recommendation fits the property.
02
Scope separation
Solar, roofing, storage, removal, and repair work are separated in the proposal so the homeowner can see what is urgent and what can wait.
03
Roof and electrical review
Roof age, attachment risk, inverter location, panel layout, shutoff rules, and access are checked before promising a simple install or repair.
04
Utility math
PSEG, Con Edison, or local utility details are reviewed against the actual bill instead of generic New York savings claims.
05
Manufacturer path
Sealing locations, materials, combustion safety, and ventilation are documented from the assessment. Duct sealing is scoped from a leakage test and coordinated with any ducted heat pump work.
06
Next appointment
Sealing is the cheapest measure with the fastest payback and it has to happen before insulation and equipment sizing. The intake asks for a quote path and preferred site-visit window so the page can turn ranking traffic into a real appointment.
Envelope leaks
The attic plane and rim joist come first.
Warm air rises and exits through every gap in the ceiling, pulling cold air in through the basement and rim joist to replace it. Sealing the top and the bottom of the house stops that stack effect.
- Foam and caulk top plates, wire and pipe penetrations, and chimney chases.
- Cover and seal recessed lights with rated enclosures.
- Weatherstrip and insulate the attic hatch or pull-down stair.
- Spray foam the rim joist to seal and insulate in one pass.
Duct leaks
Seal the ducts or waste the heat pump.
Ductwork in an unconditioned attic or basement leaks conditioned air at every joint. With a ducted heat pump, that is electric heating output lost before it reaches a register.
- Pressurize the duct system to measure total leakage.
- Seal joints, boots, plenums, and return connections with mastic or approved sealant.
- Insulate ducts that run through unconditioned space.
- Re-test to document the reduction.
Safety
Tighter house, tested appliances.
When fossil-fuel appliances stay in a sealed house, combustion safety testing confirms they still vent correctly. EnergiSense includes it whenever oil or gas equipment remains.
- Combustion appliance zone testing after sealing.
- Mechanical ventilation reviewed where the house becomes very tight.
- Moisture and attic ventilation checked before insulation depth is added.
- Fuel-switching to a heat pump removes the combustion concern entirely.
Proof
Before-and-after numbers on every job.
The blower door reading after sealing is the deliverable. It proves the work, feeds the Manual J for the heat pump, and documents the improvement for program paperwork.
- Baseline leakage recorded at the assessment.
- Post-sealing leakage recorded the same day the work finishes.
- Duct-leakage results recorded separately.
- Results attached to the EnergiSense proposal and program paperwork.
Air sealing vs. duct sealing
Two different leaks, two different tests.
| Factor | Air sealing | Duct sealing |
|---|---|---|
| What leaks | Conditioned air through the building shell. | Conditioned air through duct joints and connections. |
| Test | Blower door plus infrared scan. | Pressurized duct-leakage test. |
| Where | Attic plane, rim joist, penetrations, hatches. | Attic and basement duct runs, plenums, boots, returns. |
| Matters most for | Every home, before insulation. | Homes with ducts in unconditioned space and any ducted heat pump. |
Related paths
Sealing is step one.
Here is what follows.
Program references
The tests and measures
as the programs define them.
These are the official pages EnergiSense works from. Program status and incentive eligibility are re-verified for your address before they appear on a proposal.
Air Sealing & Duct Sealing FAQ
Questions before
the appointment.
What is a blower door test?
NYSERDA describes it as installing a fan in an exterior doorway to pull air out of the house. The pressure difference lets the assessor measure total air leakage and, with an infrared camera, see exactly where outside air is entering. EnergiSense runs it before sealing to find the leaks and after sealing to prove the result.
Where are the biggest air leaks in a Long Island house?
The attic plane: top plates, plumbing and electrical penetrations, chimney and duct chases, recessed lights, and the attic hatch. Second is the rim joist where the framing meets the foundation. Windows and doors are usually a smaller share than homeowners expect.
What is duct sealing and do I need it?
Duct sealing closes the joints, seams, and connections in supply and return ductwork so conditioned air reaches the rooms instead of leaking into the attic or basement. If the ducts run through unconditioned space, a duct-leakage test will usually show meaningful loss. It matters even more with a ducted heat pump, where every leak wastes electric heating output.
Is air sealing safe with a gas or oil furnace?
It has to be done with combustion safety in mind. A tighter house can change how atmospheric-vented appliances draft, so combustion safety testing is part of the scope whenever fossil-fuel equipment stays in the house. Converting to a heat pump removes that concern.
Does air sealing qualify for incentives?
NYSERDA lists sealing air leaks as a weatherization measure, and its Comfort Home seal-and-insulate packages pay $2,500 (attic and rim joist) or $3,000 (plus walls and floors) through participating contractors. EnergiSense confirms program status and eligibility for your address before an incentive appears on the proposal.
How long does air sealing take?
Attic plane and rim joist sealing on a typical Long Island single-family home is usually a one-day job, often completed the same day the attic insulation goes in. Duct sealing adds time based on duct length and access.
Quote + site visit
Request the quote.
Lock the next appointment.
EnergiSense reviews air sealing and duct sealing Long Island, confirms the right scope, and follows up with quote path and site-visit timing.