ROOFTOP UNITS (RTUs)

A Rooftop Unit (RTU) is a packaged HVAC system typically installed on the roof of a commercial building. It contains all major heating and cooling components within a single cabinet.

RTUs are one of the most common commercial HVAC systems used in:

  • Retail spaces
  • Office buildings
  • Restaurants
  • Warehouses
  • Medical offices
  • Schools

An RTU draws return air from the building, conditions the air, and supplies it back through ductwork.

Depending on the season, the unit can:

  • Cool the air using a refrigeration system
  • Heat the air using gas heat, electric heat, or heat pumps
  • Bring in fresh outdoor air for ventilation
  • Filter airborne dust and contaminants

Because the entire refrigeration system is contained inside the cabinet, RTUs are considered packaged units.

  • Compressors
  • Evaporator coil
  • Condenser coil
  • Supply fan
  • Filters
  • Gas burners or electric heat
  • Dampers and economizers
  • Controls and safeties

RTUs require routine maintenance to operate efficiently and reliably.

Typical maintenance includes:

  • Replacing filters
  • Cleaning condenser coils
  • Inspecting evaporator coils
  • Checking refrigerant pressures
  • Testing electrical components
  • Inspecting belts and bearings
  • Checking drain pans and drains
  • Verifying economizer operation
  • Testing safety controls
  • Dirty filters restricting airflow
  • Plugged condenser coils causing high pressure faults
  • Belt wear or failure
  • Refrigerant leaks
  • Failed motors or capacitors
  • Drain blockages
  • Ignition failures on gas heat
  • Economizer damper failures

Why Maintenance Matters

Poorly maintained RTUs consume more energy, provide less comfort, and experience more breakdowns.

Routine maintenance helps:

  • Extend equipment life
  • Reduce emergency repairs
  • Improve comfort
  • Lower operating costs
  • Prevent tenant complaints