A clothes dryer removes litres of water from a wet load, and where that water goes depends entirely on how the dryer is vented. A vented dryer pushes the moisture out of the home as hot, humid air; a condenser or heat pump dryer collects it internally. Understanding how venting works — the airflow, the lint, and the route the air takes to the outside — is the key to keeping a dryer safe, efficient and free of the moisture and fire problems that come from poor venting. This guide explains it for Melbourne homeowners.
What Dryer Venting Does
The job of a dryer vent is to carry the dryer’s exhaust air — hot, full of moisture, and carrying lint — safely out of the building. A vented dryer works by heating air, passing it through the tumbling clothes where it picks up water, and then expelling that wet air. To keep drying, the dryer continuously draws in fresh air, heats it, and expels it again. Every cycle of this process moves moisture from your clothes into the exhaust air stream.
Because a single load can release several litres of water as vapour, that exhaust air has to leave the home. If it does not — if the dryer vents into the laundry, a cupboard or the roof cavity — the moisture stays inside and causes condensation, dampness and mould, while the lint accumulates in places it should not. The vent is what makes a vented dryer safe and effective: it gives the moisture and lint a clear path outside.
Vented vs Condensing Dryers
Not all dryers vent. There are three broad types, and how each handles moisture is the key difference:
Vented dryers
A vented dryer expels its hot, moist air through a duct to the outside. It needs an external vent, but the moisture leaves the home entirely. Vented dryers are inexpensive to buy and dry quickly, but they use more energy and require the vent and lint maintenance covered in this category.
Condenser dryers
A condenser dryer cools the moist air inside the machine so the water condenses, then collects that water in a tank you empty (or plumbs it to a drain). It needs no external vent, which makes it flexible to position, but it releases some heat and a little humidity into the room.
Heat pump dryers
A heat pump dryer is an advanced condenser design that recycles its own heat rather than venting it, making it far more energy efficient. It needs no external vent and is gentle on clothes, at the cost of a higher purchase price and longer cycles. See our vented vs heat pump dryer guide.
The Vent Duct and Discharge
On a vented dryer, the vent duct connects the outlet at the back of the machine to a discharge point on an external wall or the roof. The discharge point is fitted with a vent cover — usually a flap or louvre that opens when the dryer runs and closes when it stops, keeping out weather, pests and draughts.
The discharge must be to the outside of the building. Venting into the roof cavity, under the floor, or into an enclosed space is unsafe and ineffective — it deposits moisture and flammable lint where they cause damage and hazard. A good vent run carries the air directly to an external discharge with as little length and as few bends as possible. See our installation guide for how a vent should be set up.
Lint and Airflow
Lint is the fine fibre shed from clothes as they tumble and dry, and it is central to how a dryer vent performs and how safe it is. The dryer’s lint screen catches a portion of it after every load — which is why the screen should be cleaned each time — but a significant amount of finer lint passes through the screen and travels into the vent duct.
Over time this lint accumulates on the walls of the duct, especially at bends and at the discharge cover. As it builds up, it restricts the airflow the dryer needs to expel its moist air, so the dryer works harder, runs hotter, and takes longer to dry each load. Lint is also highly flammable, so a heavily clogged vent combined with an overheating dryer is the classic recipe for a dryer fire. This is why the vent duct — not just the lint screen — needs periodic cleaning. See our guide to the signs of a blocked vent.
Duct Types and Runs
The type of duct used for a dryer vent affects both performance and how quickly it clogs:
| Duct Type | Characteristics | Best For |
|---|---|---|
| Rigid smooth metal duct | Smooth walls, least lint buildup, best airflow | The preferred choice for permanent runs |
| Semi-rigid metal duct | Flexible but firmer; moderate airflow | Short connections behind the dryer |
| Flexible foil / vinyl duct | Ribbed inside; collects lint; can sag | Generally discouraged for long runs |
Smooth rigid metal duct is the best choice because its smooth interior gives the least resistance and traps the least lint. Ribbed flexible ducting catches lint in every ridge and can sag, so it clogs faster and restricts airflow more. Whatever the duct, the run should be as short and straight as practical — manufacturers specify a maximum length with an allowance deducted for each bend, because every bend adds resistance and a place for lint to gather.
Dryer Venting in Melbourne Homes
Melbourne’s climate gives the clothes dryer plenty of work. Through the long, cool, damp winter, washing will not dry outside for days at a time, so the dryer runs frequently — load after load — shedding lint and releasing moisture each time. This makes proper venting more important than in a drier climate: the dryer is used heavily exactly when the home is already cold and humid and most prone to condensation and mould.
Many Melbourne homes also have the laundry positioned internally, away from an external wall — in a central laundry, a bathroom, or a converted space — which means a longer vent run to reach the outside. Longer runs clog faster and need cleaning more often, and where no good vent path exists, a heat pump dryer that needs no vent is often the better solution. Whatever the setup, the priorities are the same: vent to the outside, keep the run short and smooth, and clean the duct regularly. See our cleaning cost guide.