Buying or building a new home in Melbourne involves a long checklist. Air duct cleaning is rarely on it — and it should be. Builder quality standards in Victoria do not require post-installation duct cleaning, and the result is that most newly built Melbourne homes are handed over with construction debris inside the ductwork. When the system runs for the first time, it distributes whatever the builders left behind directly into the air.
This guide covers what builders leave inside new ductwork, why it matters for health and system performance, whether it applies to newly purchased homes as well as new builds, and when to schedule the clean.
What Builders Leave Inside New Ductwork
Modern Melbourne home construction involves multiple trades working in a tight schedule, and ductwork is installed relatively early in the build sequence. By the time the walls are closed, the following materials have typically entered the duct system:
Plasterboard dust
Plasterboard cutting and sanding generates fine calcium sulphate dust that penetrates every opening in the building envelope, including duct joints, register openings, and the main system unit. This is the most common contamination in new Melbourne homes. It settles in supply duct runs and the main trunk line, and compacts over time.
Insulation fibres
Ceiling batt insulation installation occurs above the ductwork in most Melbourne homes. Glass wool and rockwool fibres shed during handling and installation, falling onto and into duct runs. These fibres are respiratory irritants that are too fine for standard residential filters to fully capture.
Metal shavings and debris
Sheet metal ductwork is fabricated and installed by ducted system installers. The cutting and crimping of duct sections generates metal shavings that fall inside the duct. In flexible duct systems, offcuts of foil and polyester from duct fabrication are sometimes left inside runs.
General construction debris
Timber sawdust, grout particles, sealant offcuts, and other small-scale construction debris find their way into duct systems through register openings and supply grilles during the construction period. Register covers are protective but not airtight. See our guide to signs that ducts need cleaning for what this contamination looks like in practice.
New Purchases vs New Builds
The need for duct cleaning applies to two distinct situations: homes being handed over by a builder, and existing homes being purchased without verified service history.
New builds
For homes under construction or newly completed, duct cleaning should be scheduled after all internal works are finished and before occupancy. The system must not be run for comfort heating or cooling before the clean — doing so distributes construction debris through every room on the first use.
Purchasing an existing home
When buying an existing Melbourne home, ducted system service records are not a standard disclosure item. Ask specifically for gas heater service records and any duct cleaning invoices. If the vendor cannot provide records showing a clean within the past 5 years, assume the system needs cleaning and include it in your post-settlement budget. Homes purchased from deceased estates, investors, or long-term owner-occupiers are particularly unlikely to have service records.
Older homes with original systems
Melbourne homes from the 1970s to 1990s with original ducted systems that have never been professionally cleaned are in a similar position to new builds: the system has been accumulating contamination from the start. For pre-1990 homes, also confirm whether the duct insulation contains asbestos before booking any cleaning. See our guide on asbestos in old Melbourne ductwork.
Health Risks of Construction Debris in Ductwork
The particles generated during construction are not benign. The health risks from circulating these materials through a home’s air supply are real, particularly for vulnerable occupants.
Crystalline silica
Plasterboard cutting and tile cutting generate respirable crystalline silica — a known carcinogen and the cause of silicosis, an irreversible lung disease. While single exposure at domestic dust levels is unlikely to cause silicosis, chronic low-level exposure from a contaminated duct system running daily through winter is a genuine risk, particularly for children and elderly occupants.
Insulation fibres
Glass wool fibres irritate the respiratory tract, eyes, and skin on contact. Repeated inhalation of airborne fibres in a contaminated duct system can worsen asthma and respiratory sensitivities. Melbourne homes with new ceiling insulation should have ducts inspected for fibre contamination before occupancy.
The cumulative indoor air quality problem
Indoor air in a newly built Melbourne home that has run its ducted system for one heating season without cleaning may have higher particulate loads than outdoor air. This is counterintuitive — new homes are often marketed on their air quality — but the duct system acts as a reservoir that continuously recirculates settled debris every time the system runs. See our guide on air duct cleaning and indoor air quality in Melbourne.
When to Book New Home Duct Cleaning in Melbourne
The timing of the duct clean relative to occupancy is important:
New build: after practical completion, before first use
Schedule the duct clean after the builder’s final clean and before you move furniture in. This is the easiest access window — empty rooms, no obstacles, full access to all registers. The clean can typically be completed in one visit.
Existing home purchase: in the first 30 days
If you are purchasing an existing Melbourne home, schedule the duct clean within the first month of settlement. Early scheduling avoids the winter booking rush (April to May) and ensures you are not distributing an unknown contamination load through your new home during the first heating season.
February to April for optimal scheduling
If your settlement or handover falls in the second half of the year, February to April is the ideal booking window for pre-heating season cleaning. This is FreshDuct’s recommended timing for all Melbourne duct cleaning — see our full guide on how often to clean air ducts in Melbourne.