The Advantages And Disadvantages Of Air Handler Vs Make Up Air Unit

When it comes to ensuring adequate ventilation and indoor air quality, two essential components often come to the forefront: air handlers and make-up air units. While both play crucial roles in maintaining comfortable and healthy indoor environments, they serve distinct purposes and have unique characteristics. Understanding the differences between these two systems is critical for making informed decisions when designing or troubleshooting ventilation systems.

Air Handler: The Heart of Indoor Air Circulation

An air handler, also known as an air handling unit (AHU), is a fundamental component of a central heating, ventilation, and air conditioning (HVAC) system. It is responsible for circulating and conditioning the air within a building. The air handler typically consists of a blower, a filter, and a cooling or heating coil.

The blower draws air from the return air vents and forces it through the filter, which removes dust, pollen, and other airborne particles. The filtered air then passes through the cooling or heating coil, where it is either cooled or heated to the desired temperature. Finally, the conditioned air is distributed throughout the building via supply air ducts.

Make-Up Air Unit: Replenishing Indoor Air

A make-up air unit (MUA) is a specialized ventilation system designed to compensate for air that is exhausted from a building. This is necessary to maintain a balanced air pressure and prevent negative pressure, which can lead to air infiltration from outside and undesirable consequences such as increased energy consumption and indoor air quality issues.

The MUA unit draws fresh outdoor air into the building and conditions it to match the temperature and humidity of the indoor air. This conditioned outdoor air is then supplied to the building to replace the exhausted air, maintaining a positive air pressure and ensuring adequate ventilation.

Key Differences: Air Handler vs Make-Up Air Unit

To summarize the key differences between air handlers and make-up air units:

• Purpose: Air handlers circulate and condition indoor air, while make-up air units replenish indoor air that is exhausted.
• Air Source: Air handlers draw air from the return air vents, while make-up air units draw air from outdoors.
• Functions: Air handlers filter and condition air, while make-up air units provide fresh outdoor air to replace exhausted air.
• Pressure Control: Air handlers do not directly control air pressure, while make-up air units maintain a positive air pressure in the building.

Applications: When to Use Air Handlers vs Make-Up Air Units

Air handlers are typically used in central HVAC systems to provide heating, cooling, and ventilation for the entire building. They are suitable for most residential and commercial applications, including offices, schools, and hospitals.

Make-up air units are primarily used in buildings where large amounts of air are exhausted, such as factories, warehouses, and kitchens. They are also essential in buildings with negative air pressure issues or where fresh outdoor air is required for specific processes or safety reasons.

Energy Efficiency Considerations

Both air handlers and make-up air units can consume significant amounts of energy. However, there are several energy-efficient features available for both systems:

• Variable-speed blowers: These blowers adjust their speed to match the demand, reducing energy consumption during periods of low use.
• Energy-recovery ventilators (ERVs): ERVs transfer heat and moisture from the exhaust air to the incoming outdoor air, reducing the energy required for heating and cooling.
• High-efficiency filters: High-efficiency filters remove more particles from the air, reducing the load on the blower and saving energy.

Maintenance and Troubleshooting

Regular maintenance is crucial for both air handlers and make-up air units to ensure optimal performance and prevent breakdowns. Some common maintenance tasks include:

• Filter replacement: Filters should be replaced regularly to maintain proper airflow and indoor air quality.
• Coil cleaning: Cooling and heating coils should be cleaned to remove dust and debris that can reduce efficiency.
• Blower inspection: The blower should be inspected for wear and tear and lubricated as necessary.

Troubleshooting common issues with air handlers and make-up air units may involve:

• Reduced airflow: Check for clogged filters or blockages in the air ducts.
• Uneven temperatures: Inspect the cooling or heating coil for leaks or restrictions.
• Negative air pressure: Verify that the make-up air unit is operating properly and providing sufficient fresh outdoor air.

Final Note: Informed Choices for Optimal Ventilation

Understanding the differences between air handlers and make-up air units is essential for designing and operating effective ventilation systems. By choosing the right system for the specific application and implementing proper maintenance practices, building owners can ensure optimal indoor air quality, comfort, and energy efficiency.

Questions We Hear a Lot

Q: What is the difference between an air handler and a furnace?
A: An air handler circulates and conditions air, while a furnace heats the air. Furnaces are typically used in conjunction with air handlers to provide both heating and ventilation.

Q: Can I use an air handler without a make-up air unit?
A: Yes, you can use an air handler without a make-up air unit in most residential and commercial applications. However, make-up air units are necessary in buildings where large amounts of air are exhausted or where fresh outdoor air is required for specific processes or safety reasons.

Q: How do I determine the size of air handler or make-up air unit I need?
A: The size of the air handler or make-up air unit required depends on the size of the building and the amount of air that needs to be circulated or replaced. It is recommended to consult with an HVAC professional for proper sizing.