Herman Miller Cosm Nightfall High Back Office Chair - Fast Delivery

The Herman Miller Cosm High Back Chair in Nightfall is designed to deliver immediate comfort with almost no effort. Built around Herman Miller’s Auto-Harmonic™ tilt system, Cosm automatically responds to your body weight and movement, creating a balanced feeling of support whether you’re working, leaning back, or shifting position throughout the day.

This high back version provides additional upper back and shoulder support, making it a great option for longer desk sessions, executive workspaces, and home offices where comfort matters but you don’t want constant adjustment levers and controls.

Finished in the striking Nightfall colourway, this model combines a dark, modern aesthetic with breathable suspension for all-day comfort. Available from stock for fast, free UK delivery.

Please note: Cosm’s gas lift is intentionally designed to feel softer and more flexible (similar to car suspension) and may produce a light sound during movement.

Key Features

• High back design for extra upper back and shoulder support

• Auto-Harmonic™ tilt automatically adapts to your posture and movement

• Breathable Intercept Suspension mesh for flexible, supportive comfort

• Nightfall frame and suspension finish

• Height-adjustable arms

• Adjustable seat height

• Choice of castors for carpet or hard flooring

• Delivered by Wellworking fully assembled and ready to use

• Covered by Herman Miller’s 12-year manufacturer warranty

Wellworking Says…

“The Nightfall high-back Cosm chair combines striking aesthetics with dynamic support, automatically adjusting when you recline. A versatile option for both executive and home offices. In stock for fast, free delivery.”

Herman Miller Cosm High Back Office Chair FAQs

What makes the Cosm different from other ergonomic office chairs?

Cosm is designed to provide instant comfort with minimal adjustment. Its Auto-Harmonic™ tilt automatically balances support as you recline, so you don’t need to manually set tension controls.

What is Auto-Harmonic™ tilt?

Auto-Harmonic™ tilt is Herman Miller’s self-adjusting recline mechanism. It automatically responds to your weight and posture, providing a smooth reclining motion and consistent support.

What is Intercept Suspension?

Intercept Suspension is a breathable elastomer mesh that flexes with your body. It offers supportive comfort while remaining temperature neutral, helping reduce heat build-up during long periods of sitting.

Is the Nightfall Cosm chair in stock for fast delivery?

Yes — this Nightfall High Back specification is available for fast delivery from UK stock.

Does the chair require assembly?

No. This chair is delivered by Wellworking fully assembled and ready to use.

Why does the gas lift sometimes make a sound?

The Cosm is designed with a softer gas lift action to create a more flexible sitting feel, similar to suspension in a car. This can produce a light sound during movement, which is normal.

What castors are available?

You can choose castors suitable for carpeted floors or multi-surface castors for hard floors.

What is the weight limit of the Cosm High Back chair?

The Cosm High Back chair is suitable for users up to 159 kg (350 lbs).

What warranty is included?

The Herman Miller Cosm chair includes a 12-year, 3-shift manufacturer warranty.