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What Is a Make-Up Air (MUA) System?
A make-up air (MUA) system supplies fresh outdoor air to replace air that is exhausted from a building. When kitchens, restrooms, manufacturing processes, or general exhaust systems remove air, MUA systems restore pressure balance and prevent negative airflow conditions.
Properly engineered MUA systems support ventilation, occupant comfort, and safe operation by controlling how outside air enters the building. They can temper incoming air, integrate with heating and cooling equipment, and work alongside exhaust systems to maintain stable indoor conditions.
Without make-up air, buildings can experience drafts, pressure imbalance, comfort issues, and increased energy usage. A well-designed MUA system ensures air is replaced intentionally—rather than through uncontrolled leaks or infiltration.
PRESSURE BALANCE
MUA systems prevent negative building pressure by replacing exhausted air in a controlled, engineered manner.
VENTILATION SUPPORT
Make-up air systems deliver outdoor air to support code compliance, safety, and occupant comfort.
TEMPERED AIR DELIVERY
Incoming air can be heated or cooled to reduce drafts, stabilize indoor temperatures, and protect HVAC performance.
SYSTEM INTEGRATION
MUA systems are engineered to coordinate with exhaust fans, ductwork, and HVAC equipment for balanced operation.
MUA ASSESSMENT & SYSTEM ANALYSIS
Understanding how air enters and exits the building.
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Assessment of existing exhaust and make-up air balance
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Evaluation of pressure conditions and airflow paths
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Identification of comfort, draft, or infiltration issues
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Review of integration with HVAC and ventilation systems
Our Services
ETS delivers engineered make-up air services that restore pressure balance, support ventilation, and protect long-term building performance.
🚩MAKE-UP AIR SYSTEM Red Flags
When Should a Make-Up Air System Be Evaluated or Serviced?
Key Indicators Your MUA System Needs Attention:
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Negative building pressure or door issues
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Drafts or uneven temperatures near entrances
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Exhaust systems overpowering HVAC operation
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Cold or hot air dumping into occupied spaces
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Rising heating or cooling costs tied to ventilation
Make-up air issues often show up as comfort complaints, pressure problems, or energy waste—long before the system fully fails.
Negative Pressure
Exhaust air is not being properly replaced.
Drafts or Temperature Swings
Incoming air is not adequately tempered or distributed.
HVAC Strain
Exhaust and MUA systems are not coordinated.
Uncontrolled Outdoor Air
Air is entering without proper conditioning.
Higher Energy Use
The system is compensating for imbalance or infiltration.
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ETS HVAC Insights
Go inside our commercial HVAC projects and discover how ETS helps Central Ohio businesses upgrade systems, solve problems, and improve building performance year-round.
Frequently Asked Questions
A make-up air system supplies outdoor air to replace air that has been exhausted from a building, helping maintain proper pressure balance and ventilation.
Without make-up air, buildings can experience negative pressure, drafts, comfort issues, and increased energy use due to uncontrolled air infiltration.
MUA systems are commonly used in facilities with high exhaust demands, such as commercial kitchens, warehouses, manufacturing spaces, gyms, and healthcare buildings.
Exhaust systems remove air from the building, while the make-up air system replaces that air in a controlled manner to maintain balance and prevent pressure problems.
Yes. Make-up air can be tempered using heating or cooling components to reduce drafts, improve comfort, and minimize HVAC strain.
Insufficient make-up air can cause doors to stick, drafts near entrances, uneven temperatures, and increased energy consumption.
Many building and mechanical codes require make-up air when exhaust airflow exceeds certain thresholds, particularly in kitchens and industrial applications.
Make-up air is specifically intended to replace exhausted air, while ventilation air is often introduced for indoor air quality and occupancy requirements.
Yes. MUA systems are often engineered to work alongside air handlers, rooftop units, exhaust fans, and building automation systems.
Properly designed make-up air systems reduce uncontrolled infiltration, helping HVAC systems operate more efficiently and predictably.
Drafts, pressure imbalance, uneven temperatures, rising energy costs, or comfort complaints near entrances often indicate MUA issues.
In many cases, airflow adjustments, controls upgrades, or equipment modifications can improve performance without full replacement.
MUA systems should be inspected regularly as part of a preventive maintenance program, especially in facilities with high exhaust loads.
Engineered Temperature Solutions evaluates exhaust demand, pressure balance, and building use to design make-up air systems that integrate seamlessly with the HVAC system.
Yes. Engineered Temperature Solutions designs, installs, and services make-up air systems for commercial and industrial facilities across Ohio, engineered for local climate and code requirements.
Need MUA services in Central Ohio? Request a quote or call (614) 289-8733 to get started.
Frequently asked questions
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