Acoustic Comfort by Design: Fit-Out Strategies for Open Offices

Open-plan offices promise collaboration and efficient use of space. Yet the same layout can increase cognitive load, compromise confidentiality and make focused work more difficult.

At Deerns, we see this as a coordination challenge. Comfort is shaped less by individual products and more by how fit-out, layout and building services work together. In open-plan environments, acoustic comfort is ultimately determined by these fit-out decisions – particularly the interaction between layout, speech behaviour and building services at desk level.

Why open offices feel louder

Many projects assume that if A-weighted decibel (dBA) levels are within target, the space will feel comfortable. In practice, people do not experience sound as a single number. They experience interruptions, broken concentration and the sense that conversations carry too far.

In open offices, intelligibility is often the main source of disturbance. A conversation you can partly follow is far more distracting than a steady background hum. As a result, relying on background noise targets alone can be misleading. Two areas may measure similarly, yet one feels significantly more disruptive because speech remains clear over distance.

From an engineering perspective, acoustic comfort in open-plan environments is typically shaped by 3 recurring tensions:

• Metrics versus perception: Meeting a numerical threshold does not ensure comfort if speech remains intelligible.
• Function versus adjacency: The placement of collaborative zones, doors, circulation routes and focus desks can either contain or amplify disturbance.
• MEP versus fit-out: HVAC terminals and control strategies may shift from being unobtrusive to irritating depending on task type, sound character and local conditions. 

Fit-out is an acoustic system, not a finish

Fit-out defines the acoustic behaviour of an open office far earlier than many teams recognise. Ceilings, furniture, screens, flooring and reflective surfaces all influence reverberation and how speech decays with distance, but layout decisions often have the greatest impact.

For example, a cluster of desks positioned beside a main circulation route or near meeting room doors may experience significantly more intermittent disturbance than an identical cluster located elsewhere.

Enclosed elements such as meeting rooms and phone booths are not just amenities. When placed strategically, they interrupt sight lines, break speech paths and reduce intelligibility without the need to over-treat the entire space.

A practical way to evaluate comfort

In one of our own workplaces at Deerns, we approached the problem as an operational environment with multiple activity types and competing requirements. We combined objective measurements with a short perception check and reviewed the results by spatial cluster rather than as one overall average.

To keep the evaluation meaningful for stakeholders, we framed work as activities, not generic occupancy. In practice, the open office supports:

• Reading and text understanding
• Writing, email and reporting
• Calls and remote communication
• Collaboration at nearby desks
• Digital modelling and simulation
• Design activities requiring sustained focus

Four lessons from open plan offices

Across open plan environments, 4 important lessons surface repeatedly:

• Reverberation time is a foundation, but not the whole story: If the room is too “live”, speech becomes tiring. Even after acoustic treatment, comfort can decline when intelligible speech travels too far.
• Speech transmission is the most underestimated comfort lever: Distraction and privacy distances are practical indicators – how far speech remains intrusive, and whether people feel safe having private conversations at their desks.
• Circulation acts like a sound source: Footfall, doors opening and passing conversations create intermittent noise that disrupts deep work – particularly near entrances, amenities and meeting room edges.
• HVAC noise can comply and still irritate: Terminal noise draws complaints when it is tonal, unstable or poorly balanced against speech. Targets help, but perceived sound quality ultimately determines comfort.

Designing comfort that survives occupation

The strongest results come when fit-out, architecture and MEP are coordinated as one system, early in the design process. The most effective moves are often not expensive; they are positional and integrative.

3 key fit-out strategies consistently improve outcomes:

• Plan speech gradients deliberately: position high-speech functions so their sound does not fall directly onto focus work areas.
• Use enclosed rooms as buffers: locate meeting rooms, booths and storage to interrupt speech paths and reduce long-distance intelligibility.
• Specify HVAC for perceived quality: check not only the noise level, but also how stable and tonal the sound is under real, occupied conditions.

This approach also improves stakeholder alignment. Instead of debating pass/fail, the team can discuss sources, affected activities and interventions that reduce intelligibility where it matters most.

Who stands to benefit?

Deerns’ approach delivers clear value across the stakeholder chain:

• Occupiers benefit from improved focus, greater acoustic comfort and stronger speech privacy, supporting both productivity and wellbeing.
• Developers gain higher performing, more attractive workplaces that differentiate in a competitive market and are easier to let.
• Owners see long-term returns through fewer complaints, smoother operation and reduced need for costly retrofits or corrective measures after occupation.

Comfort is a coordination outcome

Acoustic comfort results from coordinating fit-out, adjacencies and building services as a single performance system.

At Deerns, this integrated approach is our strength. We look beyond isolated metrics and design around how people actually use a space – evaluating comfort by activity type, reviewing performance by spatial clusters, and prioritising speech behaviour not just dBA levels.

The result is open-plan workplaces that genuinely support focus and collaboration, while meeting owner expectations in day-to-day operation.