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For most of us, "airtightness" is not a term that comes up often when discussing the merits of a building, but for industry experts, air infiltration (i.e. the unintentional introduction of outside air or the loss of indoor air, typically through gaps in the building envelope and mechanical perforations) is actually a huge factor in energy efficiency, accounting for up to 30% or more of a building’s heating and cooling costs, according to the CMHC.

A recent new construction project developed by Collecdev set out to prove the merits of airtightness in multi-residential buildings. 


Their Tippet Park development is part of the Tippett Regeneration Area at Wilson Avenue and Allen Road. It implements forward-thinking planning objectives conceived by the City of Toronto and CreateTO in order to combine elegant architecture with inclusionary housing.

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This two-tower development consists of Building ‘A’ - a 13-storey condominium with 340 suites,

and Building ‘B’, which is a 16-storey purpose-built rental with 177 suites.

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At Collecdev, we are committed to being at the forefront of energy conservation and sustainability. We continuously leverage innovative building technologies and alternative energy sources in order to reduce the impact that our communities have on the natural and built environment”.

says Fernando Valenzuela, Vice President Development at Collecdev.

Industry experts agree that leaky buildings have a negative impact on HVAC performance, energy consumption, greenhouse gas emissions, comfort, and well-being. Improving the airtightness of the building envelope not only leads to healthier communities and a smaller environmental footprint, but it is also essential for meeting the mandatory energy targets outlined in Toronto Green Standard (TGS), the above-code standard set by the City of Toronto.

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“In order to build a high-performance building, you must push beyond traditional construction practices. When you look at the highest industry standards for energy and carbon efficiency, all roads require maximizing the building’s level of airtightness. An airtight building envelope is key to achieving these high standards.” 

Josh Lewis, VP of Engineering, NERVA Energy.

Any outside air that infiltrates through the envelope can lead to condensation and moisture issues - compromising the structural integrity of the building - while indoor air that escapes the envelope has a significant impact on heating and cooling requirements. Conditioned air that leaks out of the building through openings in ceilings, walls, and floors, as well as mechanical penetrations, ultimately causes unnecessary energy and carbon waste.

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"Airtightness testing is a process in which the building envelope is analyzed to quantify its airtightness. Airtightness testing measures air leakage rates through a building envelope under controlled pressurization and depressurization conditions.

We have been studying the effects of interzonal air exchanges for some time in low-rise developments, so when we heard about the project at Tippett Park, we were excited to help quantify the impact of building airtightness in a multi-residential high-rise building.”

says Gord Cooke, President at Building Knowledge Canada & Partner at Construction Instruction.

NERVA Energy, an award-winning energy advisory firm in Hamilton, Ontario is leading the charge when it comes to airtightness, deploying two aerosolized sealing technologies that virtually eliminate air leakage in the building envelope (Aerobarrier) and from ductwork (Aeroseal).

“AeroBarrier technology is a general-purpose system that seals holes as large as 1/2 of an inch, all the way down to holes not visible to the human eye – those as small as a hair follicle.


This patented technology is connected via a modified blower door to pressurize and distribute the sealing formula into the space. The pressure carries a non-toxic, water-based formula throughout the space and effectively seals any leak by using the very air that is leaking out of the room, thereby finding any leak point; visible or not.” says Josh Lewis.

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“When we were first introduced to AeroBarrier, we were intrigued by the technology and decided to deploy it in “Building B”, our purpose-built residential tower. Our goal was to evaluate the impact that aerosolized sealing could have on the building’s final airtightness performance.” says Fernando Valenzuela.


“What we’ve come to learn is that it is almost impossible to build an airtight building through conventional methods - there are just too many construction trades involved in each project. Whether it be windows, electrical, plumbing, or mechanical, these installations often create leaks in the envelope. Even on a project like this, where diligent precaution was taken to ensure high-quality construction standards, you can see how small undetectable leaks really add up.” says Josh Lewis.

The results from Tippett Park show the following KPIs:


  • Suite-level air leakage rates with the aerosolized sealant were 27% lower than conventional.*

  • ACH improvement of 47.4%

  • CFM improvement of 47.3% (@50pa)

  • TEDI reduction of 8% without ventilation, and 19.2% with ventilation


"I am immensely proud to be a part of this project. Innovative technologies and forward-thinking solutions directly impact the future of the built environment, creating value not only for our homeowners, but for the industry, the community and the planet.” says Fernando Valenzuela.

“We share Collecdev's vision to leverage advanced building technologies to create high-performance communities that promote a healthier planet.” says Josh Lewis.

To read the University of Toronto’s full abstract in the Journal of Building Engineering, click here.

*Results based on 10 unguarded blower door suite tests, completed by the Building Energy and Indoor Environment Lab at the University of Toronto and Building Knowledge Canada. doi#: 10.1016/j.jobe.2023.106528

About NERVA Energy

NERVA Energy brings together an award-winning team of engineers, certified energy managers, and seasoned mechanical technicians who work in unison to apply a multi-disciplinary approach to energy conservation. NERVA specializes in the deployment of proven prop-tech solutions along with the implementation of strategic mechanical optimization solutions that deliver significant and quantifiable energy savings and GHG reductions.


To learn more about the company and our services, visit:

Collecdev is a visionary development company dedicated to building better communities. The firm champions an integrated approach throughout the development process and is committed to being at the forefront of sustainable building practices while maintaining uncompromising standards of quality. 


To learn more about Collecdev and its award-winning communities, visit

About Collecdev

CaGBC recognizes NERVA Energy with its “Visionary Award”

About Aerobarrier Technology

Aerobarrier not only significantly lowers energy consumption for a building, resulting in operational savings, environmental benefits, and optimized HVAC function, but also improves air quality and reduces the spread of airborne disease. This advanced technology delivers a tighter building envelope thanks to an aerosolized sealant that can seal gaps as big as ½” in diameter, and as small as a hair follicle, resulting in big benefits like:


  •    A 98% reduction in air leakage

  •    Lower utility bills (up to 30%)

  •    Better indoor air quality

  •    Reduced transfer of odours

  •    Better performance for HVAC systems

  •    Improved soundproofing

  •    Protection against insects and pests

For more information visit,

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