The missing step
that makes insulation work
Air sealing seals the hidden gaps that let your paid-for heat escape — before it even reaches your insulation. Without it, adding more insulation solves only half the problem.
Insulation without air sealing is a wool sweater in the wind
Insulation slows heat transfer — but it can't stop air moving through gaps. You need to seal the gaps first.
Signs your home needs attic air sealing
Any of these are indicators that air is bypassing your insulation and escaping through the attic.
Non-stop HVAC
Furnace runs constantly but never quite reaches your target temperature — even on mild days.
Mystery drafts
Cold air movement near electrical outlets, light switches, or baseboards — even on calm days.
High energy bills
BGE or PEPCO bills significantly higher than your neighbors' or spiking unpredictably each winter.
Ice dams on gutters
Icicles mean warm air is escaping through your attic floor, melting roof snow, and refreezing at the cold edge. Air sealing stops the cycle.
The 5 biggest air leaks in Maryland homes
These aren't cosmetic gaps — each one acts like a small open window running 24 hours a day, every day of the year.
Recessed lights
Old-style "can lights" have vents in the housing that act like mini-chimneys, sucking your heated air directly into the attic around the clock — even when the lights are off.
Fix: fire-rated cap + foam sealTop plates
The gap where drywall meets wall framing at the attic floor looks small on its own — but combined across every interior wall, it's equivalent to leaving a window open all winter.
Fix: foam seal at every wall topBathroom fans
If the fan housing isn't sealed to the drywall, it pulls warm, moist bathroom air into the cold attic — a leading cause of attic mold and moisture damage in Maryland homes.
Fix: foam seal around housingAttic hatches & stairs
The attic entrance is almost always uninsulated and unsealed. Without a proper insulated cover and weatherstripping, it leaks conditioned air constantly — right at head height.
Fix: insulated cover + weatherstripWire & pipe penetrations
Every hole an electrician or plumber drilled is a permanent air leak. There can be dozens in a single home — none of them sealed at the time of installation.
Fix: expanding foam at every penetrationNot sure which of these your home has? A $100 energy audit with blower door testing and thermal imaging will show you exactly where air is escaping — before any work begins.
Book the $100 audit →What we find — and how we fix it
Every job is documented with before and after photos so you can see exactly what was sealed.
Our professional sealing process
We go beyond hardware store foam. Every material and technique follows BPI standards for a permanent, code-compliant result.
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1
Fire safety & heat shielding
Before sealing anything, we identify high-heat areas like chimney flues. These are sealed with fire-rated sheet metal and high-temperature caulking — maintaining the code-compliant clearances required around combustion appliances.
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2
Sealing the "super highways" — chaseways
Large open cavities hidden inside closets or behind walls can account for a significant share of your home's air leakage. We cap these with rigid foam board and seal every edge with two-part expanding foam to create an airtight lid.
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3
The detail work — top plates
This is the tedious work most contractors skip. We crawl to every edge of the attic to seal top plates and every wire penetration — creating a continuous, airtight layer across your entire ceiling plane.
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4
Hatch & stair treatment
We install heavy-duty weatherstripping and insulation dams around pull-down stairs or attic hatches — stopping one of the most overlooked air leaks in the house.
We test before and after — every time
Most contractors add material and move on. We run a blower door test before and after every job so you have documented proof that the work made a measurable difference.
We perform a blower door test as part of your energy audit — measuring your home's exact CFM50 air leakage and using thermal imaging to identify where air is entering.
After sealing, we run the test again. You receive a written report showing the before-and-after CFM50 numbers — typically a 20–30% reduction in air leakage, verified and documented.
Attic air sealing is BGE & PEPCO rebate-eligible
As an approved contractor for both utilities, we calculate your exact rebate during the energy audit and apply it as an instant discount — up to $15,000 for qualifying projects.
Frequently asked questions
Everything you need to know before booking.
Does air sealing or insulation come first?
Air sealing always comes first. Once loose-fill or batt insulation is installed, it's much harder to access the attic floor and properly seal gaps. Seal the envelope first, then add insulation on top.
Will air sealing cause moisture problems?
Air sealing typically reduces moisture problems by preventing warm, humid indoor air from entering cold attic spaces. If the home becomes very tight, we may recommend controlled ventilation improvements — we assess this during testing and advise accordingly.
Do I need attic ventilation baffles?
Most homes benefit from soffit baffles to keep insulation from blocking intake vents and maintain airflow from soffit to ridge. Baffles are installed before adding insulation. Air sealing targets leaks at the attic floor and does not reduce attic ventilation when vents are properly maintained.
How long does attic air sealing take?
Most jobs take half a day to a full day, depending on attic size, accessibility, and the number of bypasses identified during the energy audit.
Can I qualify for BGE or PEPCO rebates?
In most cases, yes — attic air sealing qualifies for rebates through the BGE and PEPCO Home Performance with ENERGY STAR programs. Eligibility is confirmed during the energy audit, and we handle the entire rebate application on your behalf.
Where do you perform attic air sealing?
We serve homeowners across Maryland within the BGE and PEPCO service territories — primarily Baltimore City and County, Towson, Columbia, Ellicott City, Annapolis, and surrounding areas including Montgomery and Howard counties.
Are you licensed and insured?
Yes. Leonard Home Performance is MHIC licensed (#165469), fully insured (certificate of insurance available on request), and BPI certified to perform home energy audits and weatherization work.
See the results for yourself
Every project is blower door tested before and after. Here are two recent jobs with documented results.
Attic air sealing + insulation
Attic air sealing + insulation
Services that pair with air sealing
Air sealing and insulation work best together. Your audit report will show exactly what your home needs and in what order.
Find out exactly where your home is leaking
A $100 energy audit identifies every air leak, calculates your BGE or PEPCO rebate, and gives you a prioritized plan — before any commitment to work.
Schedule a $100 Energy Audit