If your building's energy costs keep climbing despite equipment upgrades, occupants complain about drafts near exterior walls, or you're finding condensation on interior surfaces during cold weather — building air leakage problems may be the root cause. Uncontrolled air movement through the building envelope is responsible for a significant percentage of heating and cooling energy waste in commercial buildings. The U.S. Department of Energy attributes up to 40% of commercial building energy consumption to the building envelope, with air leakage being a primary contributor.
Air leakage occurs through gaps, cracks, and discontinuities in the air barrier system — at penetrations, floor-line transitions, window perimeters, mechanical equipment connections, and any location where the continuous air barrier has been compromised. These leakage paths allow conditioned interior air to escape and unconditioned exterior air to enter, forcing the HVAC system to work harder and consume more energy to maintain interior conditions.
ACE Building Envelope Design's ASTM E783 air leakage testing quantifies air infiltration rates at specific locations, producing measurable data that can be compared against ASHRAE standards and contract specifications. When combined with infrared thermography, we can visualize air pathways in real time and document the connection between air leakage locations and energy performance deficiencies.
How Air Leakage Damages Buildings Beyond Energy Waste
The energy cost of air leakage is the most visible consequence — but not the most damaging. When warm, humid interior air leaks outward through wall cavities during cold weather, it can condense on cold surfaces within the assembly. This interstitial condensation creates concealed moisture that leads to mold growth, insulation degradation, structural corrosion, and progressive assembly deterioration — all without any external water source. The U.S. EPA identifies condensation from air leakage as a major contributor to indoor mold problems.
In cooling-dominated climates like Arizona and Nevada, the moisture transport direction reverses — hot, humid exterior air leaking inward can condense on cooled interior surfaces. Both mechanisms produce concealed moisture damage that can go undetected for years while progressively compromising the building envelope assembly.
Common Air Leakage Locations and Failure Patterns
Air leakage concentrates at predictable locations in the building envelope. Floor-line junctions where the air barrier must transition from one assembly to another are common failure points — particularly in multifamily buildings with multiple floor plates. Penetrations for mechanical, electrical, and plumbing systems create holes in the air barrier that are frequently left unsealed. Window and curtain wall perimeters require continuous air barrier connection between the fenestration frame and the adjacent wall assembly.
Thermal bridging locations often coincide with air leakage paths because both are associated with discontinuities in the building envelope. Shelf angles, balcony connections, and structural penetrations that create thermal bridges also create potential air leakage paths if the air barrier is not continuously detailed through these conditions.
What You're Facing
Rising energy costs, draft complaints, condensation on interior surfaces, or HVAC systems that run constantly — and uncertainty about whether the problem is the mechanical system or the building envelope.
How We Address It
ACE's FGIA/AAMA-accredited ASTM E783 testing quantifies air leakage at specific locations, while infrared thermography visualizes leakage pathways — providing evidence that separates envelope problems from mechanical problems.
What You Get
Quantified air leakage data, identified leakage locations, targeted remediation specifications that project the performance improvement from proposed repairs.
Are Your Energy Costs Higher Than They Should Be?
Describe your building's symptoms — rising costs, drafts, condensation — and we'll explain the diagnostic approach that determines whether the envelope is the cause.
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Accredited Air Leakage Testing and Thermal Diagnostics
ASTM E783 air leakage testing quantifies air infiltration through fenestration and wall assemblies under controlled pressure conditions. This FGIA/AAMA-accredited test produces data in cubic feet per minute per square foot that can be directly compared against specification requirements and ASHRAE performance standards.
Infrared thermography provides visual documentation of air leakage patterns by detecting the thermal signature of air movement across the building envelope. When combined with pressurization, thermographic imaging can identify air leakage locations rapidly across large facade areas, directing targeted ASTM E783 testing to the specific locations where quantified data is needed.
Air Barrier Remediation and Performance Recovery
Air barrier remediation ranges from targeted repairs — sealing specific penetrations, patching discontinuities at floor lines, improving fenestration perimeter connections — to comprehensive air barrier replacement on buildings where the original system was inadequate. ACE's repair specifications are informed by the diagnostic data: we know exactly where the leakage is occurring and how severe it is, allowing targeted intervention rather than speculative whole-building approaches.
For envelope retrofits, air barrier improvement is often combined with continuous insulation upgrades and sealant replacement — addressing thermal, air, and moisture performance simultaneously. ACE's thermal performance analysis quantifies the performance improvement from proposed air barrier interventions, supporting the financial case for investment.
Related Problems Pages
Frequently Asked Questions
Gaps in the air barrier at penetrations, floor lines, fenestration perimeters, and transitions where continuous sealing was compromised during construction.
ASTM E783 accredited testing quantifies infiltration rates. Infrared thermography visualizes air pathways.
Yes — warm humid air leaking into cold wall cavities condenses, creating moisture that supports mold growth without any external water source.
Often yes — targeted repairs at identified leakage locations can significantly reduce infiltration. ACE's testing identifies exactly where to intervene.
The U.S. DOE attributes up to 40% of commercial building energy consumption to the envelope, with air leakage being a primary contributor.