The company has updated its air curtain range with brushless DC (EC) motors, cutting energy use by up to 40% compared with AC units while adding stepless speed control for entrance and doorway applications.
How the New Air Curtains Work
An air curtain projects a high-velocity stream of air across a doorway to form an invisible barrier. It reduces the exchange of indoor and outdoor air, limiting the infiltration of dust, insects, odours, and unconditioned air without a physical door that obstructs passage or visibility for people and trolleys.
Entrance air curtains are specified across retail, cold-chain, pharmaceutical, and food plants where an open doorway must stay passable yet sealed against thermal and contaminant transfer. In refrigerated loading areas the curtain reduces cold-air loss and frost formation at the threshold, while in clean or packaged-food zones it helps keep insects and outside particulates away from the process line without a physical door that slows trolleys.
The energy case for an EC drive is strongest where the unit runs many hours a day. Because an electronically commutated motor holds high efficiency across most of its speed band, the saving is realised continuously rather than only at full speed, and the stepless control lets the unit follow door traffic so it is not drawing full power against an empty lobby during off-peak periods.
Integration with a building management system turns the curtain from a standalone device into a controllable load. Linking the run signal to a door contact or occupancy schedule avoids the common fault of a unit left running against a closed door, and the same link supports run-time tracking that helps facilities teams plan cleaning and verify the unit is actually sealing when the entrance is open.
Specifiers should also weigh the acoustic side: a well-balanced BLDC rotor and a low-turbulence nozzle keep the occupied-side sound pressure below about 55 dB(A), which matters at receptions and restaurants where guests stand close to the airstream. Matching nozzle velocity to the local wind exposure, rather than over-specifying, avoids uncomfortable draughts while still holding the barrier.
With more than 30 years of HVAC manufacturing experience, the company's 80,000 m² production site and in-house performance laboratory let engineers verify discharge velocity and sound level against the actual door before shipment, so the selected length and setting match the opening rather than a generic catalogue value.
BLDC (electronically commutated) motors replace mechanical brushes with electronic commutation driven by an integrated controller. They hold high efficiency across most of their speed range, run cooler, emit less electrical noise, and typically outlast AC induction motors in continuous-duty entrance applications where the unit operates for many hours each day.
Stepless speed control lets the airflow track actual door traffic. During peak entry the unit runs at full velocity; in quiet periods it drops to a lower setting, so the curtain consumes only the energy the opening condition requires rather than running flat-out whenever the store or lobby is open to the public.
Because the motor and controller are integrated, the unit reports its state to a building management system and can be scheduled by occupancy, time of day, or a door contact, avoiding the energy waste of a unit left running against a closed door. The same link supports remote alarm and run-time tracking for facilities teams.
Performance Parameters
Selection starts from the door width and the mounting height, because the air jet must reach the floor or threshold to seal the opening. Oversized velocity wastes energy and creates uncomfortable draughts, while undersized velocity lets the barrier break down under cross draughts from wind or stack effect in tall buildings.
Nozzle velocity, delivered airflow, and sound level are the parameters that determine both sealing performance and user comfort. For most commercial entrances a discharge velocity in the range of 6-11 m/s is typical, with the unit mounted 2.5-4.0 m above the floor and the jet aimed slightly outward to counter incoming air.
Noise is a frequent complaint at service entrances. Specifying a unit with a low-turbulence nozzle and a well-balanced BLDC rotor keeps the sound pressure at the threshold below about 55 dB(A) at the occupied side, which matters in reception, retail, and restaurant settings where guests stand close to the airstream.
Air density and ambient temperature also affect delivered performance. At sites above 1,000 m the thinner air reduces mass flow, so the model should be verified against the local altitude, and the control should allow a small upward bias when sealing is critical during cold or windy weather that challenges the barrier.
| Item | Specification | Note |
|---|---|---|
| Mounting height | 2.5-4.0 m | Match to door opening |
| Nozzle velocity | 6-11 m/s | Higher for windy sites |
| Airflow per metre | 1,000-2,500 m³/h | Scale to door width |
| Sound pressure | ≤55 dB(A) | Occupied-side limit |
| Energy use | up to 40% lower | vs AC unit |
| Motor type | BLDC / EC | Brushless, variable speed |
Selection Checklist
- Measure door width and mounting height before choosing a model; width sets the required unit length.
- Choose discharge velocity for the site: sheltered lobbies need less, exposed or windy entrances need more.
- Confirm the control input matches the door: door-switch, radar, push-button, or building management system.
- Check the sound level at the occupied side if the curtain serves a reception or retail area.
- Plan filter or intake cleaning access, because dust build-up slowly reduces effective airflow.
- For cold-climate entrances, specify a heated version or pair the curtain with local heating.
About the Manufacturer
Keruite Air Conditioning Group, headquartered in Dezhou, Shandong, has more than 30 years of HVAC manufacturing experience and operates an 80,000 m² production site with its own performance testing laboratory. Products are built under ISO 9001:2015 quality management and carry CCC certification, and are supplied to customers in over 50 countries.
Our engineers respond to selection enquiries within 24 hours and can provide project-specific sizing, performance curves, and documentation to support specification and procurement.