Our Mississauga house was built in 1996 and had the original 60-CFM fans in every bathroom. After a mould issue in the main floor powder room (turns out the fan was venting into the ceiling cavity — not to exterior), we decided to replace all six at once.
Scope: 4 full bathrooms, 2 powder rooms. All fans replaced with Panasonic WhisperCeiling 110 CFM units. All ducts inspected and in three bathrooms re-routed to proper exterior wall caps.
The disaster we found: Two of the six fans were venting into the attic. This is both a code violation and the cause of our mould. The attic insulation around those duct terminations was black and had to be replaced. Add $800 to the project.
Electrician scope: Our house has an HRV (Carrier) installed in 2018. The electrician tied the new fans into the HRV controller so they can operate in coordination. Three of the six powder/bath fans now have 20-minute timers that trigger the HRV boost mode. This is proper Ontario practice for airtight houses.
Permits: ESA permit required for any new circuit. Two bathrooms needed new dedicated circuits (the powder rooms were on shared circuits). Permit and inspection: $340.
Total costs:
- 6x Panasonic 110 CFM fans: $1,140 (supply)
- Electrician (labour, 2 new circuits, HRV wiring): $1,880
- Sheet metal re-routing 3 duct runs: $920
- Attic mould remediation and insulation patch: $800
- Drywall patches x4: $640
- Permits: $340
- Total: $5,720
Every bathroom now clears steam in under 4 minutes. The mould is gone. Should have done this 10 years ago.