What Affects the Cost
Existing ducting condition. If ducting is already in place and runs to the outside, a fan swap is quick and inexpensive. Many older Sydney homes have flexible foil ducting ($8–$12/m) that has sagged, kinked, or separated at joins. Replacing degraded ducting with rigid or semi-rigid duct ($15–$25/m) adds cost but dramatically improves airflow and longevity.
Fans venting into the roof cavity. This is extremely common in Sydney homes built before the early 2000s. The fan runs, but moist air dumps into the roof space instead of outside. Correcting this requires adding a duct run and external discharge point, which costs more than a simple fan swap but prevents serious mould and timber damage.
Construction type. Inner-west terraces and older brick homes require core drilling ($150–$250) for external wall penetrations. Timber-frame homes in outer suburbs are quicker to work with.
Apartment vs house. Apartment installations involve shared ceiling voids, strata restrictions, and potentially longer duct runs to reach an external wall. Some buildings have centralised exhaust risers that individual units connect into.
Number of fans. A single bathroom fan is straightforward. Adding exhaust to a second bathroom, ensuite, and laundry multiplies duct runs and penetration points.
Electrical requirements. If the existing fan runs off a light circuit and you want a separate switch or timer, new wiring is needed. A
Fantech inline fan with a humidity sensor requires dedicated wiring from the switchboard.
Roof access. Many Sydney homes, particularly older terraces and cottages, have low-pitch roofs with very limited crawl space, making ducting installation slower and more physically demanding.
A simple bathroom fan swap with working ducting and wiring sits toward $200. Installing new exhaust fans in two bathrooms and a laundry with new ducting runs through a tight terrace roof, core-drilled external wall vents, and new switched circuits pushes toward $1,600.
Sydney-Specific Considerations
Sydney's apartment stock presents specific ventilation challenges that differ from house installations. Many apartment bathrooms, particularly in buildings from the 1960s through 1990s across Randwick, Bondi, and the lower North Shore, have no external window at all. The exhaust fan is the only source of ventilation, and if it fails, is undersized, or ducts into a ceiling void rather than outside, mould develops quickly. Sydney's coastal humidity keeps ambient moisture levels high year-round, so extraction needs are not seasonal the way they are in Melbourne or Adelaide.
In the inner west, suburbs like Marrickville, Newtown, Balmain, and Leichhardt are dominated by Federation-era terraces and Victorian cottages. These homes frequently have bathroom fans that were retrofitted decades ago and vent straight into the roof cavity. During building inspections, moisture damage to roof timbers and insulation from this setup is one of the most common findings. Correcting the ducting to vent externally is one of the highest-value ventilation improvements you can make. An inline fan like the Fantech Rapid Response 250HP ($200, delivering 349 m3/hr) mounted in the roof space with rigid ducting to a roof cowl is a reliable solution for these tight terrace roof cavities.
For apartments in strata buildings across Green Square, Zetland, Mascot, and Waterloo, body corporate approval is required for any work affecting the building exterior, including installing a new vent cowl or wall grille. Some newer buildings have pre-wired provisions for exhaust fans, simplifying the process. Older buildings may have centralised exhaust risers that individual units connect into. Allow extra lead time for strata approval, and confirm any restrictions on vent placement or appearance before committing to a quote.
Kitchen ventilation in renovated terraces and open-plan apartments is worth considering alongside bathroom extraction. Ducting a rangehood externally through a brick wall or up through the roof adds $300–$1,000 depending on complexity. If you have a gas cooktop, the National Construction Code requires external ducting, so a recirculating rangehood is not compliant. Many Sydney terrace kitchens can duct through the rear wall to the courtyard, which is shorter and simpler than routing through the roof.
Worth checking: If your bathroom fan runs but the mirror still fogs for more than 15 minutes after a shower, open the manhole and check whether the ducting actually reaches the outside. In many Sydney homes, it does not.
Hiring a Licensed Air Conditioning Technician in NSW
Ventilation installation in NSW typically involves two skill sets: an electrician for the wiring and an air conditioning technician or ventilation specialist for the ducting and fan selection. Many installers are licensed to do both.
All hardwired electrical work must be performed by an electrician holding a current licence issued by NSW Fair Trading. The electrician must issue a Certificate of Compliance Electrical Work (CCEW) for the electrical portion of the installation.
A good installer will provide the CCEW on the day of completion, not promise to send it later. You can verify a licence number on the NSW Fair Trading website. For ducting work specifically, there is no separate ducting licence in NSW, but the installer should be able to demonstrate experience with residential ventilation systems and knowledge of AS 1668.2 extraction rate requirements.
Worth checking:
Current NSW electrical licence (verify on the Fair Trading website)
CCEW issued on the day of completion
Fan extraction rate specified in the quote (minimum 25 L/s for bathrooms)
Ducting route and discharge point confirmed before work starts
If an apartment, strata approval obtained before installation day
How We Calculate
Estimates are based on surveyed trade rates for licensed electricians and air conditioning technicians in the Sydney metro area, adjusted for property age. All prices include GST. Figures cover standard residential exhaust fan and ventilation work. Commercial extraction systems and ducted air conditioning are not included.