Active vs. Passive Radon Systems: Radon Control Options for Calgary Homes

Introduction

Radon gas is one of the most serious indoor air quality risks facing homeowners in Alberta—particularly in Calgary, where clay-rich soils and common foundation designs contribute to consistently higher radon levels. As awareness grows, more homeowners are learning about the available mitigation options and are choosing proactive radon control in Calgary rather than relying solely on temporary test kits to measure exposure.

What Is an Active Radon System and How Does It Work?

An active radon system is one of the most reliable solutions for radon control in Calgary homes. Active radon mitigation systems use a continuously operating fan to create negative pressure beneath the foundation. This pressure draws radon-laden soil gases from below the slab and safely vents them above the roofline before they can enter the living space.

In contrast, passive radon systems rely only on natural air movement. Because they cannot consistently remove radon gas, passive systems are significantly less effective than active systems, particularly in high-risk regions like Calgary.

What Is a Passive Radon System and When Is It Used?

Passive radon systems are commonly installed in new home construction. They typically consist of a vent pipe routed from beneath the slab to the roofline, without the use of a fan. The intent is to reduce radon accumulation through the natural stack effect.

While passive systems provide a basic level of protection, they do not deliver the consistent radon reduction most Calgary homes require—especially during winter months when buildings are tightly sealed. For this reason, passive systems are increasingly viewed as a preliminary step rather than a complete radon mitigation solution.

Active vs. Passive Radon Mitigation: Key Differences Explained

Understanding the difference between active and passive radon mitigation is essential for Calgary homeowners. Active systems actively depressurize the soil beneath the home, preventing radon entry regardless of weather conditions. Passive systems, by contrast, simply provide a pathway for radon gas to escape.

In Alberta’s dense clay soils, passive mitigation often falls short. The choice between active and passive radon mitigation can mean the difference between achieving safe indoor air quality and experiencing long-term radon exposure.

Radon Systems With a Fan vs. Without a Fan: Performance and Effectiveness

The most significant distinction between radon systems with a fan and those without is consistency of performance. Active systems generate continuous negative pressure beneath the foundation, effectively preventing radon infiltration in all seasons.

Passive systems lack pressure control, resulting in variable performance that depends heavily on temperature, air pressure, and building conditions. This variability is particularly concerning in Calgary, where seasonal temperature swings are extreme.

Radon Prevention in New Homes: Radon-Resistant Construction in Calgary

Many new homes in Alberta incorporate radon-resistant construction techniques, such as sealed sump pits and vent pipe rough-ins. These measures typically form the basis of a passive radon system.

However, testing frequently shows that passive measures alone do not reliably keep radon levels below health-based guidelines. As a result, many homeowners choose to upgrade new-construction systems to active radon mitigation to meet long-term radon control needs in Calgary.

When and Why to Upgrade a Passive Radon System to an Active System

Knowing when to upgrade a passive radon system is critical. If post-occupancy radon testing shows levels exceeding Health Canada’s guideline of 200 Bq/m³, homeowners should convert the system to an active configuration by adding a fan.

In Calgary homes, this upgrade often becomes necessary after the first long-term radon test, particularly during winter when radon levels tend to rise due to increased indoor pressure differences.

Installation, Operation, and Maintenance

Active radon systems should be installed by trained professionals to ensure correct fan placement, airtight piping, and proper exterior venting. Once installed, maintenance is minimal—typically limited to an annual check to confirm the fan is operating correctly.

Passive radon systems may be less expensive initially, but often result in future retrofit costs when homeowners discover the system does not provide adequate radon control. Over the lifespan of a home, active radon systems generally offer better value and protection.

Final Thoughts: Choosing the Most Effective Radon Mitigation Option

Choosing between an active and passive radon system is a critical decision for Calgary homeowners. Given the region’s geological and climatic conditions, passive systems alone are rarely sufficient.

For long-term protection, homeowners should rely on comprehensive radon mitigation strategies that include active systems, regular testing, and proper maintenance to ensure consistent indoor air safety.

Frequently Asked Questions: Active and Passive Radon Systems

What is the primary difference between active and passive radon mitigation systems?

Active radon systems use a fan to mechanically remove radon gas from beneath the home. Passive systems rely solely on natural air movement and do not provide consistent radon reduction.

Is a radon system with a fan always more effective than one without a fan?

Yes. In Calgary’s climate and soil conditions, fan-powered active radon systems consistently outperform passive systems due to better pressure control.

When should a passive radon system be converted to an active system?

Homeowners should evaluate conversion after the first long-term radon test, especially if results exceed 200 Bq/m³.

Do new homes in Calgary or Alberta require passive radon systems?

There is no strict legal requirement, but many builders include passive radon systems to align with radon-resistant construction guidelines commonly used in Alberta.

How effective is radon-resistant construction for long-term radon prevention?

Radon-resistant construction reduces risk but is most effective when combined with an active radon system to ensure consistently safe indoor radon levels.

What maintenance is required for active radon systems?

Active radon systems require minimal maintenance, typically involving an annual check to confirm the fan is operating properly.