Why Make-Up Air Matters in Modern Homes

Today’s homes are tightly sealed, making them more energy efficient than ever before. While this design helps reduce energy loss, it also creates new challenges for maintaining healthy indoor air quality. Many everyday appliances — such as clothes dryers, gas stoves, water heaters, and HVAC systems — exhaust indoor air to the outside. When this air leaves the home without being replaced, the interior becomes negatively pressurized, setting the stage for a variety of air quality and comfort issues.

The Hidden Problem: Negative Pressure and Backdrafting

When a home is under negative pressure, air from outside is drawn in through any available opening — including chimneys, flues, and cracks around doors and windows. This can cause a dangerous phenomenon called backdrafting, where combustion gases from fuel-burning appliances are pulled back into the living space instead of venting outdoors. These gases often contain carbon monoxide (CO) and other harmful pollutants that pose serious health risks.

The Role of Proper Kitchen Ventilation

Nowhere is ventilation more critical than in the kitchen. Cooking generates heat, grease, moisture, smoke, and odors that must be efficiently exhausted to the outside. While kitchen range hoods help remove many of these byproducts, they also expel large volumes of indoor air. Without a system to replace that air, exhaust fans can unintentionally contribute to depressurization of the living space.

That’s where Make-Up Air Systems come in. These systems supply fresh, filtered outdoor air to replace the exhausted air, maintaining proper pressure balance and improving both air quality and comfort.

The Solution: FreshVent Kitchen Air Replacement Systems

The International Residential Code (IRC M1503.4) sets clear guidelines for make-up air in residential kitchens. When a range hood is rated above 400 cubic feet per minute (CFM) — a common capacity for high-performance gas ranges — the code typically requires a corresponding Make-Up Air Vent. This ensures that the air removed by the hood is replenished, preventing negative pressure that can interfere with the home’s HVAC performance and overall ventilation balance.

Why FreshVent Makes a Difference

A FreshVent Make-Up Air System delivers a consistent supply of outdoor air to the kitchen, allowing the exhaust hood to function at its best. Without a make-up air source, the hood can struggle to pull out smoke and cooking odors effectively, leading to:

• Reduced exhaust performance
• Increased grease buildup
• Lingering odors and moisture
• Compromised indoor air quality

By pairing FreshVent with a kitchen exhaust hood, homeowners can maintain optimal airflow. The system works in tandem with the hood to remove smoke, volatile organic compounds (VOCs), and other contaminants, while continuously introducing fresh air to balance the environment.

The Bottom Line

Make-up air is a vital component of a healthy, efficient home. In the kitchen especially, it helps maintain proper air balance, reduces pollutants, and supports a cleaner, more comfortable environment. With a system that includes FreshVent, homeowners can enjoy the benefits of powerful ventilation without sacrificing air quality — ensuring that every breath indoors is as fresh as it should be.

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