Panel Fan vs Axial Fan vs Inline Duct Fan: How to Choose

Last updated: September 10, 2026

Pressure capability decides the specification — not the airflow number in the catalogue.

Buyers often treat "panel fan", "axial fan" and "inline duct fan" as three competing products. They are not. A panel fan is an axial fan — the same propeller principle — mounted in a square wall plate instead of a cylindrical case. The genuinely useful comparison is between the three ways that principle gets packaged, because that packaging decides how much pressure the fan can generate, and pressure is what decides whether your installation works.

The Three Families at a Glance

Panel / wall fanCased axial fanInline mixed-flow duct fan
ExampleKLT seriesShort-case axialBAER inline duct fan
How it mountsFlush in a wall or window openingInline in a duct, or wall-mounted in a sleeveInline in a duct run
Air pathStraight through the wallStraight along the duct axisSwirled through a mixed-flow impeller
Pressure capabilityLowLow to moderateModerate to high
Practical duct lengthDirect, or up to about 3 mUp to about 5 m10 m and beyond
Typical airflow150 – 1,800 m³/h200 – 2,000 m³/h200 – 1,500 m³/h
Noise at the room35 – 48 dB (at the fan)ModerateLow — the fan sits away from the room
Cost per unitLowestLowHigher
Best forBathrooms, kitchens, workshops, warehouses, shedsShort ducted runs, wall sleevesLong ducted runs, ceiling voids, silent operation

Why Pressure Is the Deciding Factor

Airflow and pressure are a trade-off, and every fan sits somewhere on that curve. A wall panel fan is optimised for volume: a 12-inch KLT-20B moves 792 m³/h with almost nothing in its way. Put ten metres of duct in front of it and the same fan may deliver a fraction of that, because the duct resists the flow and the fan cannot generate the pressure to overcome it.

An inline mixed-flow fan accepts a lower free-air figure in exchange for the pressure to push air through real ductwork. That is why a hotel with a central ceiling void uses inline fans with short grille drops, while a warehouse with an open wall uses panel fans and no duct at all.

For the physics in more detail, and a two-way comparison of the ducted options, see Inline Duct Fan vs Axial Fan.

Decision by Application

ApplicationSpecifyWhy
Bathroom, direct through an external wallPanel fanShortest air path, no duct, lowest cost
Bathroom with an internal wall and a ceiling voidInline duct fanNeeds a duct run to reach outside; panel fan would stall
Domestic kitchen, wall to outsidePanel fan (plus a hood for grease)A panel fan is not a cooker hood — pair them
Restaurant kitchen, long extract runInline duct fan on the hood ductGrease filters and long duct demand pressure
Workshop or warehouse wallPanel fan, 12 to 18 inchHigh volume, no duct, cheap to install
Hotel or office, ducted to a facade grilleInline duct fanLow noise at the room and a duct run that actually works
Poultry or livestock shedPanel fan, 14 to 18 inchHigh volume and robustness matter more than noise
Cold-climate extract where heat loss mattersInline duct fan plus a back-draft damperSeal the duct when the fan stops

When to Use Both

Extract and make-up air are two halves of one system. A single panel fan extracting from a sealed workshop will underperform; the same fan with a matched inlet louvre at the opposite end will move dramatically more air for the same energy. On larger projects the usual arrangement is panel fans for extract and either louvres or a second fan for supply, sized so the two roughly balance.

Common Mistakes

Frequently Asked Questions

Is a panel fan the same as an axial fan?

A panel fan is a type of axial fan. Both use a propeller to move air along the axis of rotation. The difference is the housing: a panel fan is built into a square wall plate for flush wall or window mounting, while a cased axial fan sits in a cylindrical housing for duct or sleeve mounting.

Which is better, an axial fan or an inline duct fan?

Neither is better in general. An axial fan moves more air at low pressure and costs less, so it suits direct wall mounting and short runs. An inline mixed-flow duct fan generates more pressure, so it suits longer duct runs and installations where the fan must sit away from the room.

Can I use a panel exhaust fan with ducting?

Yes, up to roughly three metres of straight rigid duct, and you should allow 15 to 30 percent of the free-air rating for the loss. Beyond about five metres, or with two or more bends, an inline duct fan is the correct choice.

Why is an inline duct fan more expensive?

It has a more complex mixed-flow impeller, a proper casing and usually better motor and bearing specification to cope with the higher pressure duty. You are paying for pressure capability and for the ability to put the noise away from the occupied room.

What is the quietest option for a hotel bathroom?

An inline mixed-flow duct fan mounted in the ceiling void, with a short flexible drop to the ceiling grille. Moving the fan out of the room is the single most effective noise measure; a panel fan in the wall always radiates its noise into the bathroom.

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