Air Sealing for MultifamilyBuildings
3+ Units - Chicago & Suburbs
Air sealing is the single highest-return improvement you can make to a multifamily building. For 3+ unit apartment buildings, condos, and townhomes across Chicagoland, sealing the building envelope cuts heating and cooling costs, eliminates drafty units, reduces noise transfer between units, and qualifies your property for substantial utility rebates through Nicor Gas, ComEd, Peoples Gas, and NorthShore programs.
Why Air Sealing Matters for Multifamily Buildings
For 3+ unit multifamily properties, the problem is compounded by the stack effect - warm air rises through stairwells, utility chases, and shared wall cavities, pulling cold air in at the base of the building and exhausting warm air at the top. The taller the building, the more severe the effect. Air sealing is the only intervention that addresses this directly.
— WHEN REMOVAL IS NECESSARYIn a typical pre-1985 Chicago-area multifamily building, uncontrolled air leakage accounts for 30 to 50 percent of total heating costs. That's energy you're paying for, then losing through gaps in the building envelope before it ever does any work. Insulation alone can't fix it — insulation slows heat transfer through solid materials, but if air is moving freely through cracks, penetrations, and bypasses, the insulation underperforms every time.
What We Seal in 3+ Unit Properties
Building Energy Experts performs comprehensive air sealing across every layer of your building's envelope. Common targets in multifamily air sealing projects include:Attic bypasses and ceiling penetrations — top plates, electrical, plumbing, recessed lighting
Unit-to-unit and unit-to-common-area separations (a major comfort and noise issue)
Rim joists and band joists at every floor level
Mechanical and utility chases — the primary driver of stack-effect losses in tall buildings
Window and door rough openings throughout every unit
Ductwork penetrations through floors, walls, and chases
Foundation sill plates, crawl space entries, and basement-to-first-floor transitions
Elevator shafts, garbage chutes, and other vertical penetrations
What Changes After Air Sealing
Every project includes blower door testing before and after our work. The improvement is measured, documented, and delivered in your final report — no guesswork, no marketing claims.
Lower Energy Bills
Reducing uncontrolled air infiltration directly reduces the load on heating and cooling systems — lower load, lower bills, every month.
Fewer Comfort Complaints
Drafty units are the #1 tenant complaint in older multifamily. Air sealing addresses the root cause, not the symptom.
Better Soundproofing
Air gaps between units are sound gaps too. Sealing penetrations and bypasses noticeably reduces unit-to-unit noise transfer.
Reduced Pest Infiltration
The same gaps that let air in let pests in. Comprehensive perimeter sealing significantly reduces rodent and insect entry points.
Moisture Control
Controlled ventilation — achieved only after air sealing — lets you manage moisture intentionally instead of randomly.
Documented Results
Blower door testing before and after every project. Your improvement is measured, documented, and provided in writing.
Ready to Stop Paying for
Air You Lose?
Air sealing is the highest-return improvement in most 3+ unit multifamily buildings. Most properties qualify for utility rebates that significantly reduce — or fully cover — project costs.
Or call us directly: (888) 623-3769 · Crystal Lake, IL · Serving all of Chicagoland