A brief summary of various testing services that deliver thorough, accurate, independent data measuring the building envelope's performance in air, water, and thermal criteria.

Air Tightness of the Building's Envelope

Comfort & Energy

Air barrier code criteria have been introduced slowly, in measured increments, are heavily balanced by manufacturer and contractor incumbrance, and are therefore not stringent. A code-compliant thermal envelope is both relatively energy-efficient and easy for your builder to achieve.

There is little reason to fear test validation for air barrier code compliance with modern budgets, materials, and design/install practices. Even the most egregiously-detailed projects have a decent chance to meet 0.4 cfm/ft² @ 75 pa, and we offer cost-efficient pre-test diagnostic reviews that offer recommendations for improvement and make the results known prior to the formal test.

For ASHRAE 90.1, IECC 2021 C402.5.2 & C402.5.3, or project-specific air barrier performance criteria compliance, call 312.897.3742 or e-mail With the midwest’s largest CFM capacity and experience in projects widely ranging in volume and complexity, HTL is best equipped to support your project’s energy efficiency verification.

Standard Test Method for Determining Air Leakage Rate by Fan Pressurization

ASTM E1186
Standard Practices for Air Leakage Site Detection in Building Envelopes and Air Barrier Systems

ASTM E1827
Standard Test Methods for Determining Airtightness of Buildings Using an Orifice Blower Door

ASTM D4541
Standard Test Method for Pull-Off Strength of Coatings Using Portable Adhesion Testers

ASHRAE 90.1 2016 Testing

ASHRAE 90.1 2019 Testing

IECC Air Barrier Testing

USACE Test Protocol

Water-Resistive Properties
Fenestration | Cladding | Masonry | Flashing

The water-resistive performance of the building envelope is critical for structural integrity (reference nearly every recent catastrophic building collapse), indoor air quality (organic growth formation), humidity/moisture control, component deterioration and rot, etc. HTL has a complete suite of field tests to evaluate a building's water-resistive performance with lab-quality data and comprehensive report deliverables.

Hightower Labs, Inc. is an AAMA-accredited field testing agency.

AAMA 501.2-15
Quality Assurance and Diagnostic Water Leakage Field Check of Installed Storefronts, Curtain Walls and Sloped Glazing Systems [sic]

AAMA 502-21
Voluntary Specification for Field Testing of Newly Installed Fenestration Products

AAMA 503-14
Voluntary Specification for Field Testing of Newly Installed Storefronts, Curtain Walls and Sloped GLazing Systems [sic]

AAMA 511
Voluntary Guideline for Forensic Water Penetration Testing of Fenestration Products

ASTM E1105
Standard Test Method for Field Determination of Water Penetration of Installed Exterior Windows, Skylights, Doors, and Curtain Walls, by Uniform or Cyclic Static Air Pressure Difference

Standard Test Method for Field Measurement of Air Leakage Through Installed Exterior Windows and Doors

On-Site Mockup
Save cost and improve awareness of critical system detailing and transitions among on-site personnel. Rather than a remote location with, often times, little involvement from key on-site installers and documentatation of critical detailing/remediation lost in the subsequent reporting - consider an on-site or local "mini-PMU" with participation from all building envelope trades (e.g. block, framing, sheathing, vapor barrier install, rain screen, metal panels, windows, etc.).

The Building's Thermal Envelope

HTL can assist with identifying thermal bridging and other areas of concern leading to fenestration and exterior wall assemblies under-performing in the increasingly critical thermal capacity.

Our investigation and evaluation processes can provide substantive, accurate measurements of envelope thermal transmittance by measuring the enclosure's most pertinent properties (R-value and air infiltration). If the items of concern are a product of mechanical systems or use of space, then we can assist with identifying these causes as well.

Critical step in responsible envelope procurement

HTL provides on- and off-site mockup arrangements at a fraction of the cost for traditional PMU mobilizations. We are local to Chicago and therefore save travel and lodging expense for the project team & installation contractor(s).

In this environment of unreliable test and certification data, skipping the PMU is malpractice.

With HTL's budget-conscious and highly informative PMU offering, there is little reason to accept a VE deduct for pre-mobilization testing ever again.


Independent studies, industry papers, slideshows, video presentations, and other content benefiting those in the industry with the patience to read five pages, and diagrams for the developers.

  • Doing it Right

    Industry-wide, invalid and improperly executed ASTM E783 test data are not providing a reliably accurate accounting of the building's air-tightness on window wall and curtain wall systems comprising the majority of envelopes built this century and, consequently, building stakeholders are blind to their property's performance.

  • Lean

    A yearly note to re-cap adventures and observations from 2022. Longform elaborations roughly equivalent to a cardboard sign stating "the envelope deficiency epidemic is nigh."

  • Check it Out

    A presentation demonstrating the basic concepts, processes, and equipment utilized in ASTM E1105 and E783 testing, and accuracy impacts to identify when observing or performing ASTM E783 and ASTM E1105 tests.

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2-Yr Trailing Avg. Satisfied Clients
Leak Investigation Batting Avg.
Buildings Served