NexGen DOAS: Smarter Fresh Air Systems for High-Performance Buildings

Fresh air is one of the biggest factors in building health, comfort, and efficiency. With stricter codes, tighter envelopes, and growing demand for sustainable design, ventilation can no longer be an afterthought. NexGen specializes in Dedicated Outdoor Air Systems (DOAS) that make it easier to meet today’s indoor air quality and energy efficiency goals without overcomplicating your HVAC design.

What a DOAS System Really Does

A DOAS unit is designed to treat 100% outdoor air before it enters the occupied space. That process includes:

• Filtering out particulates and pollutants

• Dehumidifying to manage moisture levels

• Reheating air to a neutral temperature, typically around 72°F

By separating ventilation from space conditioning, DOAS helps buildings comply with ASHRAE 62.1 (ventilation) and ASHRAE 90.1 (energy efficiency) while giving engineers more precise control over IAQ. For owners, this translates to better occupant comfort, reduced system loads, and potential cost savings on long-term energy use.

NexGen's Innovative Product Lineup

NexGen’s DOAS solutions are built to fit a wide range of project needs—from compact, space-conscious units to rooftop systems and cold-climate solutions.

Compact DOAS: Smart Performance in a Small Package

• Airflow: 750 – 19,000 CFM

• Cooling capacity: 3 – 90 tons

• 6-row intertwined air coils for maximum heat transfer

• Scroll compressors with lead variable frequency drives

• Modulating reheat circuit for precise humidity control

• Switchable subcooling circuit for adaptable performance

• Modulating electric or gas heat options

Available with vertical or horizontal discharge, the Compact DOAS is a versatile choice for projects where space is tight but performance can’t be compromised. Its design makes it a dependable option for a wide range of applications.

Flex Series DOAS: Range, Options, and Reliability

• Airflow: 500 – 22,000 CFM

• Cooling capacity: 3 – 140 tons

• Air-source or water-source heat pump configurations

• 6-row intertwined air coils for efficient heat transfer

• Modulating reheat circuit for controlled dehumidification

• Modulating electric or gas heat options

• Switchable subcooling circuit to fine-tune system efficiency

The Flex Series is NexGen’s most adaptable platform, offering the broadest range of sizes and options. Ideal for dedicated outdoor air, mixed-air, and dehumidification applications, it gives engineers and contractors the flexibility to configure exactly what the project demands.

Aerify: Compact Energy Recovery for 100% Outdoor Air

• Airflow: 900 – 2,500 CFM

• Total energy recovery wheel

• Modulating hot gas reheat for humidity control

• ECM supply and exhaust fans for efficient airflow

• Voltage options: 208/230-3-60 or 460-3-60

• Designed for low dew point outdoor air

Aerify is a fully electric, high-efficiency unit designed for 100% outdoor air applications. With its integrated energy recovery and slim 30-inch-high cabinet, Aerify is perfect for ceiling plenums or mezzanine installations where space is at a premium.

Why Modern Buildings Need DOAS

Today’s airtight construction saves energy but often traps pollutants—CO₂, VOCs, cooking smoke, and excess moisture—that harm indoor air quality. NexGen DOAS systems bring in controlled, conditioned outdoor air to balance these environments.

• Healthcare facilities gain better infection control.

• Schools and universities benefit from improved cognitive performance.

• Offices, retail, and hospitality spaces see increased comfort and satisfaction.

• Gyms and fitness centers get effective ventilation for high-respiration spaces.

This makes DOAS not only a compliance tool but also a key contributor to healthier, more productive spaces.

Design Tips for a Successful DOAS Install

To get the most from a DOAS system, keep these guidelines in mind:

• Pair DOAS with separate sensible cooling to fine-tune temperature control.

• For VAV applications, limit turndown to 25% (20% for heat pumps).

• Follow refrigerant line limits: 200 ft. for straight-cool, 100 ft. for heat pumps, and no more than 60 ft. vertical lift.

• Stick with factory-provided controls for better compatibility with VFDs and variable compressors.

• Avoid undersized ductwork or improper vibration isolation—both can shorten equipment life.

Attention to these details ensures reliable long-term performance and fewer field issues.

Why Choose NexGen

NexGen brings together energy recovery, compact design, and advanced cold-climate engineering in a DOAS lineup that supports modern building standards. For architects and engineers, this means simpler compliance, healthier indoor environments, and systems that integrate seamlessly into both new and retrofit projects.

As codes continue to tighten and owners expect higher performance, NexGen offers a forward-looking solution for ventilation that delivers on efficiency, reliability, and occupant well-being.