Air Curtain Doors in India 2026: Sizing, Velocity & Spec

An air curtain—sometimes called an air door—is not a door at all but a fan-driven sheet of high-velocity air projected across an open doorway. Properly sized and aimed, air curtain doors form an invisible aerodynamic barrier that separates two environments while the doorway stays physically open: customers and forklifts walk straight through, but conditioned air, dust, fumes and flying insects are held back. In India's mix of hot-humid coastal cities, dusty plains and high-footfall retail, the air curtain is a workhorse for entrances that must stay open yet shouldn't bleed expensive cooling. This guide is specifier-grade: it covers what an air curtain can and cannot do, how to size it to door width and height, mounting and velocity rules, ambient versus heated units, and where it complements—rather than replaces—a physical door.

What air curtain doors actually do

The unit sits horizontally above the opening (or vertically beside very tall openings) and discharges a uniform, laminar jet of air downward across the threshold. That jet entrains and deflects cross-flowing air, so the natural exchange driven by wind, stack effect and door traffic is suppressed. A well-engineered curtain reaches the floor with enough residual velocity to deflect drafts but not so much that it blows litter inward or buffets people.

The practical payoffs in Indian projects are consistent:

• Climate separation: keeps air-conditioned retail, hotel lobbies and showrooms cool despite a permanently open door—the single biggest energy reason to fit one.
• Cold-chain protection: at chiller and freezer thresholds it limits warm-moist air ingress, reducing frost, ice build-up and compressor load. Pair it with a physical cold-storage door and PVC strips.
• Insect and dust exclusion: the downward jet is an effective fly screen—important for food, pharma and hospitality entrances under FSSAI and GMP expectations.
• Comfort and energy: it stops the cold-floor draft at lobby doors and cuts the AC tonnage wasted at the threshold.

An air curtain reduces, but never fully eliminates, air exchange. As a rule of thumb a good installation suppresses 60-80% of the uncontrolled exchange across an open door—valuable, but it is a barrier, not a seal.

Where it complements a physical door (not replaces it)

This distinction is where most specifications go wrong. An air curtain is for openings that must stay open during operating hours; it does nothing when the building is closed, gives no security, no fire rating, no acoustic value and no true airtight seal. For a pressurised cleanroom airlock, a cold-store freezer leaf or a fire compartment line, you need the engineered door and the curtain is at best a supplementary layer.

Use an air curtain with a physical door when:

• A retail or hospitality entrance has a revolving door or automatic sliding door that opens frequently—the curtain covers the open-cycle leakage the door cannot.
• A loading bay or dock door is open for vehicle access—the curtain reduces exchange while the high-speed door is up.
• A cold room uses PVC strip curtains for forklift traffic—the air curtain handles fast traffic between strip passes.

Use an air curtain instead of a door only where a physical door is impractical: a busy walk-through entrance with continuous footfall, an internal threshold between a kitchen and dining area, or a smoking/loading zone where doors would obstruct flow. Even then, treat it as an environmental aid, not a security or fire element—see the cluster complete door guide and the specialty doors overview for where rated leaves are mandatory.

Ambient vs heated units

The core split is whether the curtain merely moves air or also tempers it.

For the overwhelming majority of Indian installations—where the goal is to keep cool air in and hot air, dust and insects out—an ambient unit is correct. Heated curtains are seldom justified outside cold northern winters or specialised process anterooms, and their electrical load (often 6-18 kW for a 1.5 m unit) is a real burden. Specify heating only with a documented thermal need.

Sizing: width, height, velocity and mounting

Sizing is the heart of the specification. Get any one of width coverage, mounting height or discharge velocity wrong and the curtain fails at floor level.

Match length to door width

The combined discharge length of the unit(s) must cover the full clear width of the opening—edge to edge, with no gaps. Standard units come in nominal 1.0 m, 1.5 m and 2.0 m lengths; gang them in line for wider doors. A 3 m showroom entrance typically needs two 1.5 m units butted together. Under-covering the jambs leaves leakage channels that defeat the curtain.

Match throw to door height

The air must reach the floor with usable velocity. The taller the door, the higher the required discharge velocity and the more powerful the unit. As a rule of thumb, target a residual velocity of roughly 2 m/s at floor level; discharge velocity at the nozzle must be far higher to survive the throw. Manufacturers publish a maximum recommended mounting height per model—exceed it and the jet dissipates before it lands.

Mounting and aim

Mount the unit as close as possible above the opening, on the conditioned (inside) face, with the nozzle level with or just inside the door head. Aim the jet with a slight outward tilt (commonly 15-20° toward the unconditioned side) so wind pressure is met head-on. For openings above roughly 3.5-5 m, or where overhead mounting is impossible, use vertical side-mounted units. Always allow uninterrupted floor clearance under the jet—stacked stock or signage breaks the seal.

Standards, controls and energy context

India has no dedicated mandatory air-curtain product standard; specifications lean on international performance practice. The most-cited reference is AMCA Standard 220 (laboratory methods for testing air curtain performance), which defines how throw, velocity profile and separation efficiency are measured—ask vendors for AMCA-tested or equivalently characterised data rather than headline fan ratings. Fan and motor components fall under the relevant IS electrical-safety and IP-rating norms, and units in food/pharma zones should suit washdown and hygiene expectations (FSSAI, GMP). Air curtains are not recognised as fire or smoke barriers under NBC 2016—never substitute one for a fire-rated door or a smoke-control assembly.

For energy and operation, specify:

• Door interlock/sensor activation so the curtain runs only when the door is open—continuous running wastes fan energy and is rarely needed.
• Two-speed or variable-speed control to match wind conditions.
• Placement on the conditioned side and integration with the BMS where present.

GST on air curtains is 18%. As bands, expect ₹12,000-30,000 for a 0.9-1.0 m light-commercial ambient unit, ₹25,000-60,000 for 1.2-1.5 m commercial units, and ₹60,000-2,00,000+ for industrial and heated models—supply-only; allow extra for mounting, wiring and controls (installed cost is typically 15-30% higher). For a quick first-pass energy-loss comparison use the high-speed door savings calculator and, on cold-room thresholds, the cold-store door heat-load calculator. Final unit selection should always come from a vendor against your actual door dimensions, traffic and wind exposure—air curtains are project-engineered air-handling products, not off-the-shelf doors.

Frequently asked questions

Does an air curtain replace a door?

No. It keeps an open doorway environmentally separated, but offers no security, no airtight seal, no fire rating and no acoustic value, and does nothing when off. Treat it as a supplement to a physical leaf wherever security, fire or true sealing matters.

How do I know what size unit I need?

Match the total discharge length to the full clear door width (gang units for wide openings), confirm the model's maximum mounting height covers your door height, and target roughly 2 m/s residual velocity at the floor. Taller doors need higher discharge velocity and more powerful units—size from the vendor's published throw data.

Ambient or heated—which should I specify in India?

Ambient (non-heated) suits almost all Indian installations, where the aim is to retain AC and exclude heat, dust and insects. Heated units carry a heavy electrical load (often 6-18 kW) and are justified only in genuinely cold climates or specific process anterooms.

Are air curtains effective against flies and dust?

Yes—a correctly aimed downward jet is a recognised fly screen and reduces airborne dust ingress, which is why they are common at food, pharma and hospitality entrances. Effectiveness depends on full-width coverage, reaching the floor, and the door staying within the rated height.

Is there an Indian standard for air curtains?

There is no dedicated mandatory Indian product standard; performance is usually referenced to AMCA Standard 220 test methods, with IS electrical-safety and IP norms for the fan and motor. They are not accepted as fire or smoke barriers under NBC 2016.

What does an air curtain cost in India?

As bands: roughly ₹12,000-30,000 for a 1 m light-commercial ambient unit, ₹25,000-60,000 for 1.2-1.5 m commercial units, and ₹60,000-2,00,000+ for industrial or heated models—supply-only at 18% GST, with installation, wiring and controls extra. Get a vendor quote against your exact opening.