Yes. Replacing an aging rooftop packaged unit is a common commercial HVAC retrofit application.

However, a replacement RTU should not be selected only by matching the old unit's nominal tonnage. The existing installation should be reviewed as a complete system.

What information should be collected from the old rooftop unit?

Useful information includes:

• Manufacturer and model number
• Cooling and heating capacity
• Supply airflow
• External static pressure
• Voltage, phase and frequency
• Supply and return opening dimensions
• Downflow or horizontal configuration
• Existing rooftop curb dimensions
• Fresh-air or economizer configuration
• Control requirements

Does the new RTU have to be exactly the same size?

No.

The replacement unit should be selected according to the actual building load and current operating requirements.

If the new rooftop unit has different cabinet or duct-opening dimensions, a curb adapter or transition may sometimes be used to connect the new equipment to the existing roof opening and duct system.

Can the existing ductwork remain?

Often yes, if the duct system is in acceptable condition and can provide the airflow required by the new equipment.

The supply and return duct sizes, leakage and external static pressure should be checked before final equipment selection.

Why can replacement be an opportunity to improve efficiency?

Older rooftop units may use fixed-capacity compressors, older fan motors and lower-efficiency refrigeration technology.

A modern replacement can potentially incorporate:

• Higher IEER or seasonal efficiency
• Variable-capacity compressors
• EC or variable-speed fans
• Improved fresh-air control
• Economizer functions
• Modern building controls
• Lower-GWP refrigerant platforms

Can replacement projects qualify for energy incentives?

Potentially yes.

Some utilities and energy-efficiency programs provide incentives for replacing older commercial HVAC equipment with qualifying high-efficiency equipment. Program requirements vary by project location and should be confirmed before purchase.

For rooftop replacement projects, customers can send YUJU the existing unit nameplate, technical data, installation photographs and duct or curb dimensions for preliminary replacement evaluation.