Rooftop unit. Everything lives in one cabinet: compressor, condenser, evaporator, supply fan, filters, controls and usually a gas heat section and economizer. RTUs serve retail stores, restaurants, schools and low-rise offices, and they are serviced on the roof in all weather. Sizes commonly range from 3 to 50 tons or more.
RTU-6 over the kitchen is down on high pressure again, bring a hose, that condenser coil is coated in grease.
Also heard as
- rooftop
- rooftop unit
Related terms
AHU
Air handling unit: the cabinet of fans, coils, filters and dampers that conditions and moves air through a building's ducts.
Economizer
Dampers and controls that bring in cool outdoor air for free cooling instead of running compressors.
Condenser
The heat exchanger where hot, high-pressure refrigerant gives up heat and condenses back to a liquid.
EER
Energy efficiency ratio: cooling output in Btu per hour divided by watts of input at one hot, full-load test point.