Most older buildings in Canada—whether public or private—fail to meet even the most basic standards for indoor air quality. Residents often breathe in stale hallway air, second-hand smoke, and cooking fumes from their neighbours—without even realizing it.

In 2019, BC Housing released a report on indoor environmental quality (IEQ) in five buildings from their portfolio. While this series draws on publicly available BC Housing data, the issues identified—outdated ventilation systems, poor indoor air quality (“IAQ”), and retrofit challenges—are common in older buildings across Canada, regardless of ownership. What the report found confirmed what many building managers already suspected: these buildings relied on outdated ventilation strategies that compromised both comfort and health.

This article is the first in a three-part series using the BC Housing report as a lens into a broader problem. These five buildings rely on outdated ventilation strategies still common in many older buildings across Canada. In this series, we’ll show why those strategies no longer meet modern expectations—and how decentralized systems like Lunos provide a practical, retrofit-ready solution. The report titled "Indoor Environmental Quality of Social Housing Buildings in British Columbia", examines key indoor environmental parameters—temperature, humidity, and carbon dioxide (CO₂) levels—in existing multi-unit residential buildings (“MURBs”).

The report looked at twenty-five suites across five buildings. Four were wood-framed, low-rise buildings (four stories or fewer), and one was an eight-storey tower. All measured suites used exhaust-only ventilation, relying on corridor pressurization or open windows to draw in outdoor air. Three relied on corridor pressurization; two had exterior-facing suites with passive makeup air.

Notably, the report does not examine decentralized systems like Lunos, which operate independently at the suite level. This series aims to fill that gap—demonstrating how Lunos decentralized systems can improve indoor air quality, reduce energy demand, and enhance occupant comfort in similar buildings.

As building owners increasingly pursue ventilation retrofits for older buildings, it has become clear that many legacy ventilation strategies no longer meet modern expectations for indoor air quality, comfort, or performance.

This post is for informational purposes only and does not constitute legal, engineering, or regulatory advice. While this article discusses ventilation challenges in existing MURBs, it does not specifically reference the applicable provisions of the BC Building Code, the Vancouver Building Bylaw, or other provincial/localized codes. Always review and comply with the specific requirements of applicable codes and consult a qualified professional for compliance matters.

BC Housing defines ventilation as the process of supplying air to and/or removing air from a space for the purpose of controlling air contaminant levels, humidity, or temperature. It is an important contributor to the health and comfort of an indoor environment. Specifically, ventilation serves two primary purposes: to provide fresh air for occupants to breathe and to dilute or remove contaminants.

Poor ventilation can result in harmful pollutants and moisture being trapped in the home, which in turn can affect the health of occupants and also the deterioration of the property. Moisture is generated in homes through showering, washing dishes and clothes, cooking and even just by breathing and without effective ventilation, this moisture can be trapped and turn into condensation, particularly in the winter when surfaces such as walls are colder. The condensation can lead to damp and mould growth which can cause damage to the home, potentially lead to respiratory illnesses and result in an unpleasant living environment.

As the need for ventilation retrofits becomes clearer, the next question is how ventilation is actually provided in older buildings. At a high level, this begins with a distinction between non-mechanical and mechanical ventilation. In retrofit scenarios, that distinction matters—because while natural ventilation has historically been relied upon, modern performance and code expectations increasingly point toward mechanical solutions.

Whether it’s a new build or a retrofit (as is the case of these five buildings), when it comes to ventilation, building managers and homeowners have two main options: non-mechanical and mechanical systems:

Non-Mechanical Ventilation: Also known as natural ventilation, this method uses wind and thermal buoyancy to move air through a building via windows, vents, or other openings. While simple and passive, it can lead to drafts, inconsistent comfort, and increased heating or cooling demands. Because it depends on outdoor conditions and pressure differentials, performance is often unreliable—especially during calm weather or in tightly sealed buildings.

Mechanical Ventilation: This method uses powered components—such as fans, heat exchangers, and ductwork—to control the movement of air. It offers control over air quality and temperature, regardless of external weather conditions. Mechanical ventilation offers a more efficient, predictable and secure manner of ventilation in comparison to open windows.

* In B.C., exhaust only ventilation used by all measured suites in the report has been unacceptable in Part 9 construction since 2014. Currently the B.C. Energy Step Code requires outdoor air to be supplied directly to each suite by mechanical ventilation. This reflects an evolving understanding of how airflow, IAQ, and energy use interact in MURBs

With mechanical ventilation systems, air exchange is controlled automatically rather than relying on open windows. This allows windows to remain closed, so that the heat generated by the building’s heating system stays within the space, helping maintain stable indoor temperatures while still providing fresh air

As older buildings undergo energy upgrades and retrofits, improvements to the building envelope often make them significantly more airtight. While this reduces heat loss and improves overall energy performance, it also increases the importance of providing a reliable, controlled source of fresh air. In these conditions, mechanical ventilation is no longer optional—it becomes a fundamental requirement for maintaining indoor air quality and occupant comfort in retrofit scenarios.

Within mechanical ventilation, there are two types of systems: centralized and decentralized.

Centralized systems typically employ fewer, larger air handling units (AHUs) located on the building’s rooftop or in a dedicated technical room, distributing air to the entire building or portions of the building through a network of ducts and grilles from a central location. Centralized ventilation systems distribute air through this duct network, where delivered airflow and system efficiency are influenced by duct layout, sealing, and overall air leakage within the distribution system. When leakage occurs, conditioned supply air may not fully reach occupied spaces, and the effective removal of stale air can be reduced, meaning rooms may not receive the full ventilation rate the system is designed to provide

Both system types have their place—but decentralized systems are uniquely well-suited to retrofits, where space, cost, and disruption are key concerns.

While the BC Housing report highlights the limitations of the current ventilation strategies in these buildings, the reality is that a full overhaul of their existing systems would be costly, disruptive, and structurally challenging. Lunos offers a smarter alternative, not as a replacement, but as flexible complements that strengthen a building’s overall ventilation strategy. By working alongside centralized systems, Lunos helps owners deliver balanced airflow, address IAQ concerns, and reduce strain on aging infrastructure without triggering a full mechanical overhaul.

This approach is the foundation of a ventilation strategy: designing airflow intentionally—by combining centralized and decentralized systems to meet a building’s actual layout, condition, and usage. Lunos doesn’t compete with the existing system—it complements it. It delivers fresh, balanced air where centralized systems struggle to reach, without overhauling ductwork or disrupting tenants. The result is a tailored solution that meets code, improves comfort, and works with the building, not against it

Lunos offers several compelling advantages for both new builds and retrofits, making them a popular choice. A true ventilation strategy isn’t about selecting a single product. It’s about implementing a scalable, flexible system that delivers balanced, code-aligned performance—without gutting ceilings or disrupting tenants. Lunos makes this possible by working at the suite level, where ventilation is actually needed.

Rather than being a one-size-fits-all solution, Lunos systems can be tailored to fit the specific needs of each space. They can operate on their own or be integrated into a broader centralized/decentralized approach—forming the core of a ventilation strategy that’s customized to each building’s layout, code requirements, and occupant needs. 

This article introduces the theory behind these strategies. Upcoming posts will dive deeper into technical comparisons, system configurations, and design scenarios where Lunos outperforms traditional solutions in real-world applications.

Simplified Installation with minimal structural impact (Centralized systems are structurally invasive by design)

Ducted systems require ceiling drops, soffits, and bulkheads—transforming your building to fit the equipment. Lunos fits the building. Each unit installs directly through an exterior wall, with no need to reconfigure walls, ceilings, or shared infrastructure.

• Only small 6.25” wall openings are required, eliminating the need for ductwork
• Direct-to-source airflow removes the risk of duct leakage
• Quick, straightforward installation using low-voltage wiring
• Ideal for older or space-limited buildings with low ceilings or tight wall cavities

Lower Costs (Centralized systems require more infrastructure by design)

Centralized systems come with high design, installation, and maintenance costs—because they’re built to serve an entire building from a few centralized locations. Lunos avoids this complexity entirely by working at the suite level. No ductwork, no mechanical rooms, no need for hallway pressurization or balancing dampers.

• Simplify installation to reduce labor and materials
• - Require only filter changes—no costly ongoing maintenance contracts
• - Operate on low voltage (1.4–3.3W per pair)
• - Reduce reliance on corridor-supplied air, decreasing the energy demand on central air handling units (AHUs
• - Provide direct airflow without ductwork inefficiencies
• - Recover heat from exhaust air to lower heating costs

Enhanced Flexibility (Centralized systems remove control)

In a centralized system, airflow is balanced at the building level. In a decentralized system, each suite becomes its own ventilation zone. Lunos gives building professionals the ability to tailor installations suite by suite—ensuring each space meets ventilation requirements without overcomplicating the system. Each installation can be tailored to the suite’s layout, climate, and usage patterns, enabling smarter design—not just blanket airflow.

This design-level flexibility helps building professionals respond to real constraints—without compromising performance or compliance.

Air quality (Centralized systems distribute air unevenly)

When ventilation is designed around a single mechanical core, air often travels the path of least resistance. Some suites get stale air, while others experience drafts or pressure imbalance. Lunos delivers filtered, balanced air directly into each suite—no shared ductwork, no cross-contamination, no IAQ trade-offs.

Lunos decentralized HRVs improve indoor air quality by supplying filtered outdoor air directly into each suite—while also preventing cross-contamination, unwanted odors, and pest intrusion.

• Suite compartmentalization
  Each Lunos unit ventilates individual suites independently, helping maintain true compartmentalization. This prevents cross-contamination from adjacent units and common corridors, which is a common issue in older buildings using centralized or passive ventilation.
• Built-in bug screens
  Every Lunos unit includes a fine-mesh bug screen that prevents insects and pests from entering the building—offering an added layer of comfort and protection, especially in buildings where windows and wall penetrations may not be fully sealed.
• Filtered outdoor air
  Lunos units filter incoming air to remove dust, pollen, and airborne pollutants—making them ideal for residents with allergies or respiratory sensitivities, and for buildings in urban or wildfire-prone areas.

Want to see how decentralized ventilation fits into your building’s strategy?

Good ventilation is no longer a nice-to-have. It’s essential for health, energy performance, and code compliance. In our next post, we’ll walk through how building owners and engineers can retrofit older buildings with decentralized HRVs—without tearing open walls or displacing tenants. Contact our team for expert guidance on retrofit-ready ventilation solutions.

Explore Real-World Retrofit Applications

To explore technical considerations, system configurations, and real-world retrofit applications, see the examples below demonstrating how LUNOS can transform ventilation in aging buildings across Canada.