We all want our businesses to be comfortable, but sometimes our HVAC systems need a little help. If you've noticed some rooms feeling stuffy or humid, the issue could be a lack of make-up air. Here's an overview of what make-up air is and how it works with your HVAC system to maintain indoor air quality.

What Is Fresh Air Make-Up?

Our experts want customers to know that make-up air, also called outside air, is fresh air from outside that is intentionally brought into a building. It makes up for the air that is removed by ventilation systems. HVAC systems all expel indoor air to the outside. This can lower indoor air pressure and create imbalances. Opening windows allows some outside air back in, but make-up air is a controlled, intentional way to replace exhausted air.

Why Is Fresh Make-Up Air Needed?

Without sufficient make-up air, an HVAC system may struggle to keep rooms comfortable. Negative pressure causes air to infiltrate through gaps in walls, doors, and windows. This unconditioned air can feel drafty and increase humidity as warm and moist air from outside condenses on cooled indoor surfaces. We explain to customers that make-up air systems draw in filtered, conditioned outside air to balance air pressure. This helps humidify or dehumidify the indoor air to comfortable levels.

How Does a Fresh Air Make-Up Unit Work?

A dedicated make-up air unit works alongside your HVAC system. We tell our customers that it contains a blower and ventilation louvers that allow fresh air directly into your business's ductwork. The air first passes through a filter to remove dust, pollen, and other contaminants. In a heated make-up air system, the air then flows past a heating element to warm it to room temperature before circulating. This prevents the uncomfortable sensation of cold outside air entering the building. The system monitors indoor air pressure and adjusts the amount of make-up air to maintain balance.

According to the U.S. Department of Energy, air cooling products are the most desired in the United States, accounting for about 57.8% of HVAC market revenue in 2022. With proper make-up air, your HVAC system can provide cool, comfortable air more efficiently. If your business feels stuffy or you notice humidity issues, ask your HVAC professional about installing a make-up air system. Breathing that fresh, temperate outside air will make your indoor environment more pleasant. Reach out to Scientific Building Automation to learn more about HVAC systems or a make-up air unit and how it may benefit you.