What is the average cost for a complete radon sub-slab depressurization system with a RadonAway fan in the GTA?

A complete radon sub-slab depressurization system with a RadonAway fan typically costs $2,500-$4,500 installed in the GTA, depending on your home's foundation type, basement layout, and exterior routing requirements.

The system works by creating negative pressure beneath your basement slab, drawing radon gas from the soil and venting it safely above your roofline through a dedicated pipe system. RadonAway fans are the industry standard — their RP145 and RP265 models are most common for residential installations, with the fan size determined by your home's soil conditions and foundation characteristics.

System components and typical GTA pricing breakdown:

• RadonAway fan unit: $400-$600


• PVC piping (4-inch diameter): $200-$400 depending on routing distance


• Sump pit modification or core drilling: $300-$800


• Electrical connection (dedicated 15-amp circuit): $300-$500


• Exterior routing and roof penetration: $400-$800


• Manometer (pressure gauge) and warning system: $150-$250


• Labour and installation: $800-$1,500

GTA-specific considerations significantly affect pricing. Toronto's clay soil conditions often require more powerful fans to overcome soil resistance. Homes in areas like Scarborough, North York, and Mississauga with heavy clay may need the larger RP265 fan versus the standard RP145. Winter installations cost 10-20% more due to frozen ground conditions and roof work complications.

The installation process involves core drilling a 4-inch hole through your basement floor (typically near an existing sump pit), installing a suction point beneath the slab, running PVC piping up through the house and out through the roof or exterior wall, and connecting the RadonAway fan in an unheated space like your garage or attic. The system runs continuously, drawing about the same power as a 60-watt light bulb.

Post-installation testing is critical — the system should reduce radon levels below 200 Bq/m³ (the Canadian guideline), with most effective systems achieving levels below 100 Bq/m³. Follow-up testing 30-90 days after installation confirms effectiveness, and annual testing ensures continued performance.

When to hire a certified professional: Radon mitigation requires specialized knowledge of soil conditions, fan sizing, and proper venting to prevent radon re-entry. Look for contractors certified by the Canadian National Radon Proficiency Program (C-NRPP) or similar credentials. Improper installation can actually increase radon levels or create negative pressure that draws radon through other pathways.

Many GTA homeowners discover radon issues during basement renovation projects — if you're planning basement finishing, test for radon first. Installing the mitigation system before finishing is much easier and less expensive than retrofitting through finished walls and ceilings.

Need help finding a certified radon mitigation contractor? Toronto Basement Remodeling can match you with local professionals experienced in radon systems for GTA homes.