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Two different commercial problems, both solved with a fan, and both routinely solved with the wrong one.

The first is heat and stale air inside a space — a workshop, a warehouse, a commercial kitchen. The second is losing conditioned air and gaining insects and humidity through a door you cannot keep shut. The first needs extraction. The second needs an air curtain. Neither is a bigger circulation fan.

High-pressure industrial fans: what "high pressure" means

A domestic ventilating fan moves air through a short, clear opening. A commercial one usually has to push against something — a long duct run, a louvre, a filter, a greasy kitchen hood, or simply a room already under pressure from other equipment. A fan that is only rated on airflow in free air will disappoint badly once it has to work against resistance.

KDK's high-pressure range is built for that. Slim housings that fit a wall thickness without a custom frame, and a drain mechanism that keeps water and dust out of the motor — which in Singapore is not a nice-to-have, given what gets driven through a wall opening during a storm.

Sizes run from 25cm up to 60cm. As a rough guide, the 45cm 45GSC moves 5,200 m³/h on 227W at 51 dB(A). To size properly, work out the volume of the space and how many air changes per hour the use demands — a storeroom is a handful, a commercial kitchen is many times that. Tell us the room dimensions and what happens in it and we will do that arithmetic with you.

Smaller rooms and single-bay workshops: 25GSC, 30GSC, 35GSC, 40GSC.

Larger spaces: 50GSC and 60GSC.

GSC or GTC? The difference that actually matters

These look like the same fan in the same size, and the price difference tempts people toward the GSC without asking why the GTC exists.

The GTC models — 45GTC, 50GTC, 60GTC — add a totally enclosed motor that prevents abnormal temperature rise, a rated ambient range of −10°C to +50°C, and the option to install horizontally or vertically. The 45GTC also runs slightly harder than the 45GSC: 5,420 m³/h on 240W against 5,200 m³/h on 227W.

In plain terms: GTC is the one to specify where the air the fan is pulling through is hot, dirty, greasy or chemically unpleasant, or where the fan itself sits somewhere hot — a kitchen extract, a plant room, a mezzanine under a metal roof, a spray or process area. A motor that cannot shed its own heat in a 40°C roof space is a motor that fails early.

GSC is the right choice for general warehouse and workshop ventilation, where the air is just warm and dusty. Most people genuinely need the GSC. The ones who need the GTC usually already know their environment is hard on equipment.

One practical note on both: installation is not included. These are heavy units — a 45cm fan is around 19kg — going into a wall opening, and that is a contractor's job with a proper frame and weatherproofing.

Air curtains: the shopfront problem

If you run anything with a door that stays open during trading — a shop, a clinic, a coffee shop, a loading bay, a food unit — you already know the cost. Your aircon escapes, humid outside air walks in, and so do flies. Closing the door costs you walk-in customers, so nobody does.

An air curtain blows a downward sheet of air across the opening fast enough to form a barrier. Warm humid air and insects do not cross it easily; people walk straight through without noticing. For an F&B unit it is also a hygiene measure, not just a comfort one.

The 2509UA is a useful reference point: a 900mm unit, 1,000 m³/h on high, 9.0 m/s outlet velocity, 71W, 46 dB(A).

How to read the air curtain model numbers

This is the part nobody explains, and it makes the whole range obvious once you see it. The model number encodes two things: the effective door height, then the unit length.

2509UA — effective to 2.5m, 900mm long. 3009UA — 3.0m, 900mm. 3509UA — 3.5m, 900mm. 2512UA — 2.5m, 1200mm. 3512UA — 3.5m, 1200mm. 4012UA — 4.0m, 1200mm.

So sizing is two measurements and no guesswork.

Match the length to the door width. The curtain must span the whole opening — a gap at either end is a gap in the barrier, and the unit stops doing its job properly. For a wide opening, install two or more units side by side rather than one undersized one.

Standard shop door, roughly 900mm wide: 2509UA, 3009UA or 3509UA depending on height. Double door or wide entrance around 1200mm: 2512UA, 3512UA or 4012UA.

Match the effective height to the mounting height. This is where people get it wrong and then conclude air curtains do not work. The air has to still be moving fast enough when it reaches the floor. Mount a 2.5m unit over a 3.5m opening and the barrier runs out of energy halfway down, leaving the bottom metre wide open — which is exactly where the insects and the heat come in. Measure from the floor to where the unit will actually sit, and buy for that number or above it.

All six have an adjustable deflection vent, so you can angle the stream slightly outward once it is in. That adjustment is worth doing properly on commissioning rather than leaving at the factory setting.

Installation is not included on these either.

Which one for which premises

Workshop or warehouse that gets unbearable in the afternoon: a GSC fan sized to the volume, mounted high so it pulls the hot air off the ceiling rather than the cool air off the floor.

Commercial kitchen: a GTC, because of the heat and grease the motor has to live with.

Retail or F&B shopfront: an air curtain matched to the door, and the honest answer is that it will pay for itself in aircon alone if your door is open all day.

Both, in a lot of cases. Extraction at the back, curtain at the front.

Smaller premises, domestic sizes

If what you actually have is a bathroom, a small kitchen or a store room rather than a factory, the industrial range is the wrong shelf. KDK's domestic ventilating fans — ceiling-mount, wall-mount, window-mount and two-way — cover that, and we go through them in our guide to choosing a ventilating fan.

And if the goal is simply to make a space feel cooler rather than to move air out of it, that is a circulation fan, not ventilation: see which KDK ceiling fan for a Singapore flat.

Tell us the opening

Specifying these from a web page is where mistakes happen. Send us the door width and height, or the room dimensions and what the space is used for, and we will size it properly before you commit to anything.

645 Geylang Road, Singapore 389575 — +65 6546 7446
2 Gambas Crescent #03-19, Nordcom Two, Singapore 757044 — +65 6255 3446

WhatsApp +65 8978 9808, or browse the full KDK range.