With the continuous shift toward open-plan kitchens and induction cooktops, the way architects need to plan ventilation has become more demanding and more consequential to the final design. The choice between a downdraft and overhead rangehood isn't purely about aesthetics anymore; it's about ensuring the structural design, cabinetry layout, ceiling construction and extraction performance are all compliant and functional.
What’s the Difference Between Overhead vs Downdraft?
Each rangehood system was developed to solve a different ventilation problem. That’s why, before getting into formats and product specifications, it’s worth being clear on what each principle is doing mechanically.
How Downdraft Rangehoods Work
Downdraft systems, extract laterally or downward rather than overhead. This means they pull vapour across the cooking surface and into a benchtop-level capture point, creating a vapour path that bypasses the ceiling entirely.
There are two primary configurations:
• Pop-up units, which rise from the benchtop when in use and retract when not
• Flush-integrated units, which sit permanently level with the benchtop surface
Downdraft was specifically engineered for use with induction cooktops, where lower heat and vapour output makes lateral extraction effective. This makes them particularly suited to island bench configurations where overhead extraction is structurally impractical or aesthetically incompatible with the design intent. Explore our full downdraft rangehoods range to find your project’s best fit.
How Overhead Rangehoods Work
Overhead rangehoods rely on the natural movement of heat and vapour. Cooking releases steam, grease, smoke and combustion by-products that rise vertically; allowing an overhead system to draw any smoke through an extraction duct, or in some cases a recirculation filter. This means that overhead rangehoods are often a more efficient option for high-heat and high-vapour cooking environments.
Types of Overhead Rangehoods
So, what are the popular types of overhead rangehoods? These overhead formats serve different design intents and project conditions. Choosing between them comes down to whether the rangehood should be a feature of the kitchen or maybe just a concealed support element. Let’s dive deeper into each option:
Canopy Rangehoods
Canopy rangehoods are a popular overhead format[EB1.1][LH1.2]. The hood itself is the visible shape that hangs over the cooktop, available in both wall-mounted and island canopy configurations. Wall-mounted canopies sit flush against a wall behind the cooktop, while island canopies are suspended from the ceiling with a chimney that conceals the ductwork above.
Canopy formats are a popular choice for projects where the rangehood is intended to be visible, often as a deliberate design feature. The chimney detail on an island canopy can also help to anchor an open-plan kitchen zone. Explore the full canopy rangehoods range for specification-grade wall-mounted and island canopy configurations.
Undermount Rangehoods
Undermount rangehoods are integrated within overhead cabinetry above the cooktop, with only the underside of the unit visible. The hood draws vapour upward through the cabinet structure into ducting concealed within or above the joinery. This suits kitchen projects where the design intent calls for a clean cabinetry line rather than a visible hood. It’s important to note that the performance is comparable to canopy systems at equivalent specifications, and the format is widely used in both traditional and contemporary kitchen styles where cohesion of cabinetry takes priority.
Slide-Out Rangehoods
Slide-out rangehoods sit beneath an overhead cupboard and extend horizontally when in use, retracting back into the cabinetry when the rangehood is off. This makes the format well suited to compact kitchens where benchtop and ceiling real estate are at a premium, or perhaps the client prefers a rangehood that disappears from use when not actively in use.
Ceiling Cassette Rangehoods
Ceiling cassette rangehoods are concealed within the ceiling cavity, with only a flush grille visible from below. This combines the extraction performance of an overhead canopy with a fully concealed aesthetic that preserves uninterrupted ceiling planes. The format is particularly strong for island bench configurations, where a traditional canopy with a chimney would disrupt the design or compete with pendant lighting.
How to Match the Right Ventilation to the Cooktop
The cooktop is a primary variable that helps to determine what extraction format will perform. This means that when you specify the ventilation without reference to the cooktop, it can lead to mismatched capacity, ducting conflicts and underperforming kitchens. The three scenarios below cover the majority of residential projects.
Gas Cooktops
Gas cooking generates high volumes of combustion by-products, moisture, heat and airborne grease. As a result, the traditional specification has been an overhead canopy or another overhead format sized appropriately to the burner output. Overhead extraction remains the standard recommendation for the majority of gas applications.
However, the category has started to shift. Several manufacturers now produce gas-rated downdrafts, which are engineered to handle the heat and combustion by-products that gas cooking produces. These ratings are quoted in megajoules per hour (or MJ/h), measuring how much energy a gas cooktop outputs at full capacity. Some downdrafts are now rated for cooktops up to 58.32 MJ/h, which covers the highest-output residential gas cooktops on the market, including pit gas configurations. This makes gas-rated downdrafts a viable option for projects where overhead extraction is structurally impractical, such as island layouts without ceiling access, or where it doesn't suit the design intent.
Induction Cooktops
Induction cooktops generate considerably less heat and vapour than gas, which makes lateral extraction a strong fit. Downdraft is often the preferred specification for induction-only kitchens, particularly in island bench layouts or design-led projects where a clean ceiling is part of the intent. Overhead extraction is also a viable option for induction; which means the choice between overhead and downdraft for induction usually comes down to kitchen layout and design intent rather than performance grounds. For more information on specifying induction, see our guide to induction cooktop specification.
High-Output and Mixed Configurations
Some projects specify mixed configurations, such as an induction cooktop alongside a separate wok burner, or commercial-style gas ranges with multiple high-output zones. For these configurations, overhead extraction at higher airflow capacity is the standard specification. However, some gas-rated downdraft models may be a viable option. Speak to our team to determine if this is a good fit for your option.
Onboard vs Offboard Motors
Beyond the rangehood format itself, motor placement is another important consideration in the specification. The choice between onboard and offboard motors affects noise levels, extraction performance, installation complexity and ongoing service access.
Onboard Motors
Onboard motors (also known as internally-motored rangehoods) are built directly into the rangehood unit, with the motor and fan housed inside the hood. The ducting is then fitted to the motor outlet and run to the external atmosphere. Onboard configurations are simpler to install, with no remote motor location to coordinate and no separate cable run, which typically means lower installation costs.
They are available in single, twin and triple motor configurations to suit different kitchen sizes and extraction requirements. While the historical trade-off has been noise levels, modern onboard motors have closed much of that gap through improved fan design and acoustic engineering.
Offboard Motors
In contrast, offboard motors are located away from the rangehood unit, typically outside the home on the roof, eave or wall, within the ceiling cavity or even beneath the floor.
A power cable connects the motor back to the hood, and ducting is run between the hood, the motor and the external atmosphere. The main benefit is noise. With the motor relocated away from the kitchen, the noise of extraction is transferred outside the room, with a noticeable improvement in living amenity, particularly in open-plan or entertainer kitchens. Additionally, there is also a performance advantage with motors that are mechanically more efficient.
Ducting, Recirculation and NCC Compliance
Ductwork is the most underestimated part of rangehood specification. The route, length, diameter and termination directly determine how a rangehood performs, and in new residential construction, ducting is also where compliance with the National Construction Code is decided.
NCC and Australian Standard Requirements
Under NCC 2022, Part 10.8.2 (Condensation Management) sets out the requirements for kitchen exhaust. Exhaust from a kitchen or kitchen rangehood must discharge directly, or via a duct or shaft, to outdoor air. As such, clause F8D4 of the Housing Provisions specifies that an exhaust system installed in a kitchen must have a minimum flow rate of 40 L/s, and confirms that a rangehood installed in a kitchen must comply with F8D4(2). The NCC also references AS 1668.2 (Mechanical Ventilation and Air-Conditioning) as the applicable Australian Standard for ventilation systems.
The practical implication for new residential builds is that ducted rangehoods are effectively the default for compliance. Industry commentary from building certification professionals interprets the discharge clause as meaning that recirculating rangehoods do not generally satisfy the NCC exhaust discharge requirement in new construction. Recirculating remains a useful option in some retrofit and apartment scenarios where external ducting is not possible, but it should not be specified as a default for new builds without confirming compliance with the relevant building surveyor.
Coordinating Rangehood Ductwork at the Design Stage
Duct planning should be locked in during schematic design, not construction documentation. As such, each format has its own routing requirements:
• Island canopy installations route through the chimney and externally to the roof.
• Ceiling cassette formats require adequate ceiling plenum depth for the unit and the duct run.
• Downdraft formats route ducting beneath the benchtop and through the cabinetry, often requiring floor penetrations in multi-storey projects.
In all cases, duct diameter and run length directly affect extraction efficiency. Longer or narrower runs reduce performance and need to be compensated for with higher motor capacity. Confirm the route and termination with the builder, HVAC consultant and, where relevant, the structural engineer during design rather than during commissioning.
Specify with Confidence at Designer Appliances
Specifying kitchen ventilation well comes down to working through the decisions in the right order, and that order almost always belongs at schematic design! Once the cooktop and the kitchen layout are decided, the extraction format usually follows, which in turn shapes the ducting route and motor strategy. Architects who work through this sequence early end up with kitchens that perform as briefed and integrate cleanly with the rest of the design, while those who leave it until commissioning end up reworking around constraints that could have been resolved on paper.
At Designer Appliances, we work alongside architects and designers across a range of residential and multi-residential projects to support kitchen specification decisions from concept through to handover. With access to the full range of rangehoods, including specification-grade options from leading brands, our product experts can help guide you through the full project from formatting to ducting decisions and more! Speak to our team to specify your next kitchen with confidence today.
Overhead vs Downdraft Rangehood FAQs
What is the difference between overhead and downdraft rangehoods?
Overhead rangehoods sit above the cooktop and capture rising vapour through formats including canopy, undermount, slide-out and ceiling cassette units. On the other hand, downdraft rangehoods extract laterally or downward from beside or behind the cooktop, drawing vapour across the cooking surface to a benchtop-level extraction point.
Can a downdraft rangehood be specified with a gas cooktop?
Yes, but only with a gas-rated model. Some downdrafts are now rated for cooktops up to 58.32 MJ/h, which covers the highest-output pit gas configurations on the market, so always confirm the rating against the cooktop's MJ output before specifying.
Which overhead rangehood format is best for an island bench?
Ceiling cassette rangehoods are often the strongest island bench option because they sit flush within the ceiling and preserve uninterrupted ceiling planes. However, island canopy rangehoods are also a strong choice where the canopy is intended as a feature. Both require early coordination with the structural engineer to confirm ceiling layout or canopy support.
When should I specify onboard vs offboard motors?
It’s best to specify onboard motors for simpler installations where cost and ducting complexity are priorities and noise is less critical. On the other hand, offboard motors should be specified for noise-sensitive applications such as open-plan or entertainer kitchens or bedrooms above the kitchen, long duct runs, or island configurations where motor noise would sit in the social zone.
Which rangehood type is better for an island bench?
Downdraft is typically the better specification for island benches. This is because it preserves uninterrupted ceiling planes and avoids the structural complexity of running ductwork through the ceiling. However, ceiling cassette rangehoods are another strong option for island bench configurations, as they sit flush with the ceiling for a clean and minimal aesthetic.