Pneumatic Actuators vs. Electric Actuators: Which Is Right for Your Valve Automation Project?

Valve automation is at the heart of modern industrial process control. From chemical plants and power stations to water treatment facilities and food processing lines, automated valves ensure precise, reliable, and repeatable flow control without the need for constant manual intervention. The two most common ways to automate a valve are with a pneumatic actuator or an electric actuator — and the choice between them can have a significant impact on performance, safety, and total cost of ownership.

At Valves UK, we supply a comprehensive range of both pneumatic and electric actuators, including brands such as Air Torque, Hytork, Festo, Valbia, Koei, and Bettis. In this guide, we'll compare the two technologies across a range of key criteria so you can make the best decision for your project.

How Pneumatic Actuators Work

Pneumatic actuators use compressed air to generate the mechanical force needed to open or close a valve. A supply of compressed air at a specified pressure (typically between 4 and 8 bar) is directed into a cylinder, pushing a piston or rack-and-pinion mechanism that rotates or strokes the valve stem. There are two main configurations: Double Acting (DA), where compressed air is used to both open and close the actuator, giving greater torque in both directions and faster cycle times; and Spring Return (SR), where compressed air opens (or closes) the actuator while a spring brings it back to its default fail-safe position in the event of air supply failure.

How Electric Actuators Work

Electric actuators use an electric motor — typically AC or DC — to drive a gear mechanism that opens and closes the valve. They can be powered from standard mains supply or from low-voltage DC supplies. Electric actuators often include a position feedback signal (such as 4-20mA or 0-10V), limit switches, and manual override capabilities.

Speed and Torque

Pneumatic actuators are generally faster, with cycle times of under a second for small sizes. Electric actuators are typically slower, especially at higher torque ratings, though this is not usually a problem for most process applications. Both types can be configured to provide very high torque; however, pneumatic actuators can deliver extremely high torques at relatively compact sizes, especially in double-acting configurations.

Fail-Safe Operation

Spring-return pneumatic actuators are the gold standard for fail-safe applications. In the event of air supply or power loss, the spring returns the valve to a known safe position (either fail-open or fail-closed). Electric actuators can also be fitted with spring-return or battery backup systems, but these add cost and complexity.

Energy Efficiency and Control

Electric actuators are generally more energy efficient — they only consume power when moving, whereas a compressed air system requires a continuous running compressor which uses significant energy. Electric actuators with modulating control (e.g., 4-20mA input) offer excellent position accuracy and can throttle valves to any position, making them ideal for proportional flow control. While pneumatic actuators can also be fitted with positioners for modulating control, the system is more complex and maintenance-intensive.

Environmental Suitability and Installation

Pneumatic actuators are inherently suitable for use in hazardous and explosive atmospheres (ATEX zones) because they contain no electrical components. Electric actuators require ATEX-rated models for such environments, which are more expensive. If you already have a compressed air network on site, adding pneumatic actuators is straightforward. If you don't, installing an air supply system is a significant capital investment. Electric actuators only require a power supply, making them the simpler choice for sites without compressed air.

Which Should You Choose?

Choose a pneumatic actuator if: you have an existing compressed air supply on site; you need fail-safe spring-return operation; you're working in a hazardous or explosive atmosphere; you need very fast cycle times; or you need high torque in a compact size.

Choose an electric actuator if: you don't have compressed air on site; you need precise modulating control (4-20mA, 0-10V); you're installing in a remote location with power but no air; energy efficiency is a priority; or you need integrated position feedback without additional components.

Our Range

At Valves UK, we stock pneumatic actuators from Air Torque, Hytork, Festo, Valbia, and Bettis — covering spring return and double acting configurations in a wide range of torque outputs. For electric actuation, our Koei range includes the popular Unic-05, Unic-10, and Unic-20 models, as well as modulating actuators with 4-20mA control. All of our actuators are compatible with standard ISO 5211 mounting flanges and can be matched with our full range of ball, butterfly, and globe valves. Contact our technical team for help sizing and selecting the right actuator for your application.