- Conditions up to 100% outside air to help you meet ventilation code requirements
- Humidity control
- Low dewpoint
- Energy efficient
- Ideal for commercial buildings with high or fluctuating ventilation rates
- Double-wall insulation for efficiency and quieter operation
Horizon® Dedicated Outdoor Air Systems (DOAS Unit)
Models OAB, OAD, OAN, OANG
Overview
Trane’s Horizon® DOAS optimizes buildings by efficiently supplying conditioned outdoor air, controlling humidity, and preventing mold.
- Configuration Options: With or without ERV, air-cooled, water-cooled, air-sourced heat pump, water-sourced heat pump
- Heating Options: Electric, Hot Water and Gas
- Scroll Compressors: Standard and Digital
- Space Control: Single zone, multi-zone VAV, make up air
- Voltage: 208v, 460v, 575v
- Refrigerant: Next-gen, low-GWP R-454B
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Higher Standards
Horizon DOAS supplies up to 100% outdoor air to meet ventilation code requirements. It maintains proper supply air dewpoint at both full and part load conditions, eliminating excess moisture. These units are AHRI 920 compliant, achieving optimal efficiency in moisture removal.
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Energy Efficient
By preconditioning air and reducing the load on traditional HVAC comfort systems, Horizon DOAS units boost energy efficiency. Built with a double wall insultation and an insulated drip pan, Horizon DOAS ensures efficient and quieter operation.
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Precision Performance
With a supply air dewpoint of ≥ 43°F at full and part load, Horizon exceeds traditional standards for occupant comfort. Horizon DOAS units are engineered for rigorous performance specifications, providing precise year-round dehumidification control access across the enthalpy map. Count on Horizon for consistent and reliable performance, regardless of the season.
Product Information
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OAB
- Tonnage Range: 3 – 9 tons
- Airflow Range: 500 – 3,000 CFM
- Cooling Options: DX, Chilled Water
- Heating Options: Indirect-Fire Gas Heat, Electric Heat, Hot Water Heat, Heat Pump
- Gas Heater Range: 50 – 200 MBH
- Electric Heater Range: 5 – 48 kW
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OAD
- Tonnage Range: 10 – 30 tons
- Airflow Range: 1,200 – 8,000 CFM
- Cooling Options: DX, Chilled Water
- Heating Options: Indirect-Fire Gas Heat, Electric Heat, Hot Water Heat, Heat Pump
- Gas Heater Range: 150 – 600 MBH
- Electric Heater Range: 15 – 119 kW
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OAN
- Tonnage Range: 30 – 60 tons
- Airflow Range: 3,000 – 13,500 CFM
- Cooling Options: DX, Chilled Water
- Heating Options: Indirect-Fire Gas Heat, Electric Heat, Hot Water Heat, Heat Pump
- Gas Heater Range: 300 – 950 MBH
- Electric Heater Range: 10 – 215 kW
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OANG
- Tonnage Range: 40 – 80 tons
- Airflow Range: 4,000 – 20,000 CFM
- Cooling Options: DX, Chilled Water
- Heating Options: Indirect-Fire Gas Heat, Electric Heat, Hot Water Heat
- Gas Heater Range: 200 – 1200 MBH
- Electric Heater Range: 15 – 229 kW
Product Information
Application Guides
Installation Operation Maintenance (IOMs)
Integration Guides
FAQs
Your DOAS questions, answered.
Trane dedicated outdoor air systems are designed to handle the ventilation needs of a building separately from its heating and cooling functions.
Dedicated outdoor air systems cool and dehumidify 100% of outdoor air before directing it to occupied building zones, helping to meet ventilation standards, decrease indoor humidity, and reduce the load on HVAC systems.
A dedicated outdoor air unit operates by taking in outside air and filtering the air to remove particles and contaminants. It will then pre-condition the air (heating or cooling). The air is then further conditioned to dehumidify and reach the required temperature and humidity levels for ventilation. The DOAS unit will then distribute the conditioned outside air through the building’s ventilation system, independent of the local HVAC equipment that manages the heating and cooling of the space.
Local HVAC units are responsible for handling the specific cooling and heating needs of each zone. Lastly, DOAS will use the exhaust air from the building to precondition the incoming outdoor air before exhausting outside. By treating outdoor air separately from recirculated air, DOAS units ensure adequate ventilation airflow and maintains control over humidity levels.
As a general guideline, size the dedicated outdoor air unit offset both the ventilation load and the space latent loads during peak outdoor-enthalpy condition.
DOAS units typically pair with traditional HVAC equipment that does heating and cooling. Terminal equipment like VRF, water sourced heat pumps, fan coils, blower coils, and sensible cooling terminal units also are appropriate.
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Horizon® Dedicated Outdoor Air Systems (DOAS Unit)
Models OAB, OAD, OAN, OANG
Horizon DOAS units are designed specifically to condition 100% outside air year-round, reduce latent loads, enhance the entire building system’s comfort and energy efficiency, and maintain your building’s health. It eliminates excess moisture, preventing discomfort and the health risks associated with mold and microbial growth.
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