Retrofit challenges: Upgrading FCUs in older Dubai hotels

Upgrading fan coil units in older Dubai hotels is rarely a straightforward equipment replacement exercise. Many of these properties were designed decades ago under different load assumptions, acoustic expectations, and control philosophies. While guest comfort standards have increased, the underlying infrastructure often remains constrained by space, access, and operational continuity requirements. As a result, retrofitting a modern fan coil unit into an ageing hotel environment introduces technical challenges that must be addressed at the design, installation, and commissioning stages.

1. Space constraints and non-standard FCU footprints

Older hotels frequently feature FCUs installed above bathroom ceilings, within tight bulkheads, or behind custom joinery. These installations were often tailored to manufacturer-specific dimensions that no longer align with current product ranges.

Modern FCUs, even when more efficient, may have:

• Larger coil face areas to improve heat transfer
• Thicker insulation for acoustic performance
• Integrated control valves and sensors

This creates conflicts with existing ceiling void heights and access panels. In many retrofit projects, engineers must either redesign mounting arrangements or select custom-sized units that balance performance with physical limitations.

2. Chilled water system compatibility

Older chilled water systems were typically designed for higher flow rates and larger temperature differentials. New-generation FCUs are often optimized for different ΔT values and lower water volumes.

When a modern fan coil unit is connected to an older chilled water loop without a hydraulic assessment, common issues include:

• Poor heat exchange
• Inconsistent room temperatures
• Excessive valve hunting
• Reduced chiller efficiency

Successful retrofits require careful review of coil selection, control valve sizing, and balancing strategies to ensure compatibility with the existing plant.

3. Acoustic expectations vs legacy infrastructure

Guest expectations for acoustic comfort have increased significantly. However, older hotels often lack proper vibration isolation, duct attenuation, or acoustic lining within FCU enclosures.

Installing a quieter fan coil unit alone is not enough. 

Retrofit teams must also consider:

• Fan speed control strategies
• Mounting isolation methods
• Air velocity through existing grilles and ducts

Ignoring these factors can result in noise complaints even when new equipment is installed.

4. Controls integration and building automation limitations

Many older hotels operate with legacy control systems or partial automation. Modern FCUs are designed for integration with advanced BMS platforms, featuring EC motors, modulating valves, and digital communication protocols.

Challenges arise when:

• Existing BMS cannot support new communication standards
• Control wiring is limited or undocumented
• Guestroom management systems require coordination

In some cases, FCU upgrades must include parallel control upgrades or hybrid solutions that bridge old and new systems without disrupting hotel operations.

5. Phased installation and operational continuity

Unlike new builds, hotel retrofits must be executed with minimal disruption. Rooms cannot remain out of service for extended periods, and noisy or dusty work must be carefully scheduled.

These forces retrofit teams to:

• Prefabricate piping and valve assemblies
• Standardize installation procedures
• Coordinate closely with hotel operations

Time constraints often limit commissioning windows, increasing the importance of accurate pre-installation design and factory testing.

6. Drainage and condensate management

Older FCU installations often rely on gravity drainage with limited slope or ageing piping. New units with higher latent capacity can generate more condensate, exposing weaknesses in existing drain lines.

Failure to address drainage compatibility can lead to:

• Water leakage
• Ceiling damage
• Guestroom downtime

Retrofit designs must reassess drainage routes and traps rather than assuming compatibility.

Upgrading a fan coil unit in an older Dubai hotel is not a plug-and-play replacement. It requires a holistic understanding of space constraints, chilled water behavior, acoustics, controls, and hotel operations. Retrofit success depends less on selecting the latest FCU model and more on engineering integration that respects the limitations of existing infrastructure while meeting modern comfort and efficiency expectations.