Daycare Ventilation, By the Numbers (A Plain-English Guide to ASHRAE 62.1)

Instructions:

As a childcare director, you are an expert in early childhood education, safety, and creating a nurturing environment. You may not, however, be an expert in mechanical engineering. Yet, one of the most critical factors for keeping children and staff healthy is happening invisibly in the air around them: ventilation.

When we talk about preventing the spread of respiratory viruses like RSV, influenza, and the common cold, we often focus on handwashing and surface cleaning. While essential, these steps only address part of the problem. A growing body of evidence shows that ensuring a continuous supply of fresh, clean air is a primary defense against airborne transmission.

But what does “good” ventilation actually mean? The industry standard comes from ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers), and their guidance, specifically Standard 62.1, provides the numbers. This guide will translate those technical standards into plain English and provide practical steps you can take.

Why Daycares Have Higher Ventilation Requirements

A crowded daycare classroom presents a greater airborne risk than a typical K-12 classroom for a few key reasons. Young children have developing immune systems, engage in close-contact play, and tend to have higher rates of respiratory illness. They are, in engineering terms, a significant source of bioaerosols.

Recognizing this, ASHRAE Standard 62.1 sets higher outdoor air requirements for daycare facilities compared to schools for older children. The standard requires a specific amount of fresh outdoor air to be delivered to a space, calculated based on both the number of people in the room and the size of the room itself. More people in a smaller space means you need more fresh air to dilute germs and keep the air healthy.

Using CO₂ as a Practical Proxy for Air Quality

You don’t need to be an engineer to get a sense of your facility’s ventilation. You can use a simple, powerful proxy: a carbon dioxide (CO₂) monitor.

Humans exhale CO₂. In a well-ventilated space, that CO₂ is quickly diluted by incoming fresh air, and levels remain low. In a poorly ventilated space, CO₂ builds up. Because people exhale respiratory viruses along with CO₂, high CO₂ levels are a direct indicator of high airborne transmission risk.

A portable, non-dispersive infrared (NDIR) CO₂ monitor is an affordable tool that can give you real-time insight. Placing one in each classroom can transform your understanding of your building’s performance throughout the day.

CO₂ Level (ppm)	What It Means	Practical Guidance
< 800 ppm	Good Ventilation. Your system is effectively diluting contaminants.	Continue standard operations. This is your target zone.
800 – 1,100 ppm	Marginal Ventilation. The air is getting stale, and risk is increasing.	Time for simple actions: open windows/doors (if safe), move activities outdoors, or temporarily reduce occupancy in the space.
> 1,100 ppm	Poor Ventilation. The risk of airborne transmission is significantly elevated.	This requires intervention. It’s a clear signal to deploy portable air cleaners or call for HVAC service.

Practical Steps for Better Air

Armed with data from a CO₂ monitor, you can take practical steps to improve your air quality.

1. Upgrade Your Filters

This is often the single most impactful and cost-effective upgrade. Check the filters in your HVAC system. They should be rated MERV 13 or the highest rating your system can handle without impeding airflow. MERV-13 filters are highly effective at capturing the small respiratory particles that can carry viruses. Make sure they are inspected monthly and replaced on schedule (usually every 3 months).

2. Deploy Portable HEPA Air Cleaners

In rooms that consistently show high CO₂ levels, or during a known respiratory outbreak, a portable HEPA air cleaner is your best friend. HEPA (High-Efficiency Particulate Air) filters are certified to remove at least 99.97% of airborne particles, including viruses. Ensure the unit is sized correctly for your room to provide at least 5 air changes per hour (eACH).

3. Maintain Your System

Schedule regular preventative maintenance for your HVAC system with a qualified technician. This ensures the system is running efficiently, the outdoor air dampers are open and working correctly, and the equipment can achieve the ventilation rates it was designed for.

Communicating with Parents and Staff

Air quality data isn’t just for you—it’s a powerful tool for building trust. Parents are more informed and concerned about health and safety than ever before. Being transparent about the steps you’re taking to ensure healthy air can be a major differentiator for your center.

Consider creating a simple “Healthy Air” section on your parent portal or a small sign near your entrance. You can share things like:

“Our facility uses MERV-13 filters to help keep our air clean.”
“We monitor our classrooms with CO₂ sensors to ensure good ventilation.”
“During flu season, we add portable HEPA filtration to our playrooms for extra protection.”

This proactive communication demonstrates a sophisticated, evidence-based commitment to their child’s well-being, turning an invisible safety measure into a visible, confidence-building asset.

Good ventilation is a cornerstone of a healthy childcare environment. By understanding the standards, using simple tools to measure performance, and taking practical steps to improve, you can significantly reduce the risk of illness and keep your classrooms safe, healthy, and open.

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