In brief
Chain actuators suit most tilt, top-hung and roof windows: compact, quiet and barely visible on the frame. Linear and spindle actuators lift heavy skylights and large roof sashes, at Vent Systems up to 5000 N. Rack-and-pinion actuators are suited to long strokes and wide sashes such as continuous rooflights. What matters is sash weight, opening width, installation space and the voltage, 24 V or 230 V.
What is a chain drive?
A chain drive is an electric window drive that opens and closes the window by means of an extending, self-supporting chain. It is mounted on the frame or the sash and is suitable for bottom-hung, top-hung and roof windows – for daily ventilation as well as for smoke and heat exhaust ventilation (SHEV). Typical values are 24 V or 230 V, forces of 250 to 1500 N and strokes of up to 1000 mm. You will find suitable models under Chain actuators.
In brief: Chain actuators suit most bottom-hung and top-hung windows and are particularly compact. Linear or spindle actuators are suited to heavy rooflights and roof windows, rack-and-pinion actuators to very large and heavy sashes. The deciding factors are force, stroke, space on the frame and voltage (24 V or 230 V).
Straight to the shop: Chain actuators · Spindle actuators · Rack and pinion actuators
Decision table: which actuator for which window?
| Situation | Recommendation | Typical values | Model |
|---|---|---|---|
| Tilt or top-hung window, normal size | Chain actuator | 250–1,500 N, stroke 100–1,000 mm | VS-KA |
| Wide sash | Double chain actuator | 800 N, stroke up to 1,400 mm | VS-DKA 800 |
| Actuator should be invisible | Concealed chain actuator | 300 N, stroke 100–1,000 mm | VS-CKA 300 |
| Heavy rooflight dome or roof window | Linear actuator (spindle) | 600–5,000 N, stroke 100–800 mm | VS LA |
| Large, heavy sash with long stroke | Rack-and-pinion actuator | 800 N, stroke up to 1,000 mm | VS-ZA 800 |
| Several actuators in sync or building management system | i-series with Modbus | depending on model | VS-KA-i, VS-LA-i, VS-ZA-i |
| No power supply | Mechanical chain operator | Stroke 50–400 mm | VS-MKA |
Check force and stroke precisely: Window actuator calculator · All actuators compared
Choosing the right Window drive is crucial for the functionality of a building, be it for daily use natural ventilation or for safety in case of fire by Smoke and heat exhaust systems (SHEVS). Depending on the window type, weight and installation situation, different drive technologies offer specific advantages.
1. Chain drives: The compact all-rounders
Chain actuators These are the most commonly used drives for facade windows. They are particularly popular because they are compact and visually unobtrusive.
- Area of application: Ideal for vertical facade windows and lightweight roof windows.
- Special feature: They can often be concealed within the window profile, thus preserving the window's aesthetic appeal.
- Technology: A chain extends from the housing and opens the sash. Modern versions offer intelligent features such as an anti-pinch function.
2. Linear actuators (spindle drives): Powerful for heavy loads
When large lifting distances or heavy window elements need to be moved, Linear actuators (often also called spindle drives) are the first choice.
- Area of application: Especially suitable for heavy roof windows or skylights.
- Special feature: They offer high compressive and tensile strength (often up to 1,500 N or more).
- Technology: A rigid rod (spindle) extends linearly from the housing. They are more robust against wind loads on the roof than simple chain drives.
3. Rack and pinion drives: Robustness for extreme cases
Rack and pinion actuators They are considered the "workhorses" of window automation and are used where maximum stability is required.
- Area of application: Large skylights, heavy louvered windows, or projects with extreme mechanical requirements.
- Special feature: They are extremely resistant and durable, even under harsh environmental conditions.
- Technology: Power is transmitted via a gear to a solid rack.
Decision criteria for B2B partners
When planning, you should consider the following technical factors in addition to the type of drive:
- Operating voltage: 24 V DC is mostly used for smoke and heat exhaust ventilation systems (with backup batteries), while 230 V AC is efficient for everyday comfort ventilation.
- Energy requirement: The calculation is done in Newtons (N). The heavier the window and the larger the required opening angle, the greater the force must be.
- Safety: In public buildings, pinch protection is essential to prevent injuries at the main closing edges.
Comparison of drive technologies
Window drives compared
The right technology for every project
Conclusion: The choice depends on the wing weight, installation location, and the desired level of design.
Are you unsure which drive system is right for your project? Contact us – we will advise you individually and, if desired, create a suitable technical data sheet or a tender specification.
Suitable products: VS-KA chain actuator (250–1500 N), VS-LA linear actuator (600–5000 N) and VS-ZA 800 rack-and-pinion actuator (800 N). You can find an overview of all drives in the Vent Systems Shop.
How to retrofit existing windows for electric opening is shown in the guide Retrofitting electric window openers.
Read more: How Much Does an Electric Window Actuator Cost? Prices, Installation, Replacement
Frequently asked questions
Which window actuator is suitable for façade windows?
Usually a chain actuator. Chain actuators are compact, visually discreet and can often be installed concealed in the window profile. They are ideal for vertical façade windows and light roof windows.
When is a linear actuator the better choice?
For long strokes and heavy elements such as roof windows or rooflights. Linear actuators (spindle actuators) offer high push and pull forces and are more robust against wind loads on the roof than simple chain actuators.
What are rack-and-pinion actuators used for?
For large rooflights, heavy louvre windows and projects with extreme mechanical requirements. The force is transmitted via a gear wheel onto a solid rack – this makes rack-and-pinion actuators particularly resistant and durable.
24 V or 230 V – which operating voltage is the right one?
24 V DC is mostly used for smoke and heat exhaust (SHEV) systems with emergency power batteries. 230 V AC is suitable for everyday comfort ventilation.
Suitable products at Vent Systems
- All chain drives in the shop
- All linear actuators in the shop
- All rack and pinion drives in the shop
Read more: 01 Chain drive for facade windows – typical applications at a glance · Rack-and-pinion drives in building automation
Read more about spindle actuators in the guide Spindle actuator for windows and skylights. Everything about rack-and-pinion actuators can be found in the guide Rack-and-pinion actuator for windows. For large opening angles, the VS-SB 400-i with side-bending chain, for synchronised sashes the smart rack-and-pinion actuator VS-ZA-i.
Questions about the selection process? Contact us – We will advise you on drive systems, controls and accessories.
Technically reviewed by Dietmar Heiken, Sales, Vent Systems HDI GmbH, Hamburg – around 20 years of industry experience. Questions? Phone +49 40 50694631 or info@ventsystems.de
Last updated: 26.10.2026
Questions? 040 50694631 · info@ventsystems.de
