A Rooftop Package Unit (RTU) is a self-contained HVAC system placed on the roof of a commercial or industrial building. It contains all major components (cooling, heating, and air handling) inside a single unit — hence the name “package.”
Main Components of Rooftop Package Unit
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Compressor
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Compresses refrigerant to circulate and remove heat from indoor air.
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Evaporator Coil
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Cools the air as the refrigerant absorbs heat from the return air.
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Condenser Coil
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Releases absorbed heat to the outside air via fans.
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Air Filter
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Removes dust and pollutants from incoming air.
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Blower Fan (Supply Fan)
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Pushes conditioned air into the building’s duct system.
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Heating Section
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Can be electric, gas-fired, or heat pump-based.
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Mixing Box (optional)
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Mixes return air with fresh outdoor air (for ventilation).
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Economizer (optional)
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Uses cool outdoor air to reduce the load on compressors.
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Working Principle
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Warm air from the building is drawn into the RTU.
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The air passes through filters and is cooled (or heated) using refrigerant or gas/electric heating.
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The conditioned air is pushed back into the building via ductwork.
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Heat is rejected through the condenser fan to the outside environment.
Common Applications
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Shopping Malls
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Office Buildings
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Restaurants
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Theaters
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Schools