Indoor Air Monitoring To Increase IAQ

# Indoor Air Monitoring To Increase IAQ

Preface: This article with embedded podcasts was designed to educate contractors on indoor air quality and indoor air quality monitoring. Use this as a tool to educate your customers and help them stay informed about creating healthier indoor environments.

Understanding the Three Main Factors of IAQ

Shortly after the Covid-19 pandemic turned our industry upside down, I had an enlightening conversation with Brandon Glancy from Aprilaire on my podcast. We dove deep into the three main factors that determine indoor air quality – concepts I knew about but had never fully explored.

The three main factors of IAQ include humidity, filtration, and ventilation.

When we master these factors while maintaining comfortable temperatures, we create superior indoor air quality in our customers’ homes and businesses. As HVAC professionals, gaining a strong understanding of these factors – how to measure them and how to address issues the data reveals – has become more critical than ever.

Let’s explore each factor and understand why monitoring is the key to solving IAQ problems.

Check out the podcast episode to learn more:

Humidity: The Goldilocks Zone of Indoor Air

Finding the right humidity level is like Goldilocks searching for the perfect porridge – it needs to be just right.

Too much humidity creates moisture problems and potential mold growth. Too little leaves occupants dealing with dry skin, irritated sinuses, and that annoying static shock when touching doorknobs or sliding on work pants in the morning.

But humidity affects more than just comfort. Extreme levels in either direction can damage building materials like hardwood flooring and drywall. Recent research shows that airborne viruses travel more easily in dry air, while higher humidity levels help contain viruses in heavier water droplets that fall to surfaces rather than remaining airborne.

Multiple studies indicate that maintaining 40-60% relative humidity creates the ideal environment for minimizing virus transmission while preventing moisture-related issues.

Winter Humidity Challenges

Keep in mind that excessive humidity can create condensation on windows or in areas with air infiltration during cold weather. This occurs when building materials reach or drop below the air’s dew point – a critical concept for understanding moisture control. Poor ventilation, especially during cooking activities, can exacerbate these condensation issues.

Generally speaking, we need to humidify spaces in winter and dehumidify in summer, though each building has unique requirements based on its construction, occupancy, and use patterns.

Beyond Basic Air Conditioning

While air conditioning systems naturally remove moisture through condensation on the cold evaporator coil, this dehumidification stops when the thermostat is satisfied. If humidity levels remain high after the cooling setpoint is reached, the space faces risks of moisture damage and mold growth.

This is where dedicated dehumidifiers prove their worth. These units cool air to remove moisture, then reheat it to avoid overcooling the space – maintaining both temperature and humidity at optimal levels.

Filtration: Moving Beyond MERV 8

Throughout my career, I’ve changed countless MERV 8 filters. While they protect equipment reasonably well from dirt and debris, they leave much to be desired for protecting human health. Even with regular filter changes, evaporator coils still need periodic cleaning.

The MERV (Minimum Efficiency Reporting Value) rating system, developed by ASHRAE (The American Society of Heating, Refrigeration and Air Conditioning Engineers), provides a standardized way to evaluate filter effectiveness.

During my conversation with Brandon, we discussed why MERV 13 should be the minimum standard for protecting both equipment and human health. The ability to measure PM2.5 (particulate matter 2.5 micrometers in size) becomes crucial when planning filtration solutions.

Understanding PM2.5 and Health Risks

PM2.5 represents fine particulate matter that poses significant health risks due to its ability to penetrate deep into lungs and even enter the bloodstream. This is why the industry increasingly points to MERV 13 as the minimum standard for human protection – these filters can capture particles from 0.3 to 1 micrometer, as shown in the chart below from the National Air Filtration Association.

Implementing MERV 13 Filters Properly

The Covid-19 pandemic has driven increased demand for MERV 13 filtration, but I strongly caution against simply swapping filters without proper testing. Here’s the right approach:

1. Perform baseline airflow testing with the existing filter
2. Install the MERV 13 filter and retest airflow
3. Conduct heating and cooling system checks to ensure:

• No excessive temperature rise across the heat exchanger
• Adequate airflow to prevent evaporator coil freezing

1. Monitor filter loading frequency, as higher-efficiency filters may require more frequent changes depending on the environment

Ventilation: The Fresh Air Solution

Ventilation plays a massive role in maintaining healthy indoor air. While we can filter and condition indoor air, nothing beats replacing stale air with fresh outdoor air. The most effective approach uses either an HRV (heat recovery ventilator) or ERV (energy recovery ventilator), depending on climate and specific requirements.

Without proper ventilation, buildings accumulate harmful pollutants including:

• VOCs (volatile organic compounds) from cleaning products and building materials
• CO2 (carbon dioxide) from human respiration
• Excess moisture from cooking, bathing, and breathing

Real-World Ventilation Testing

I conducted experiments in my own home using the Haven IAQ monitor to demonstrate ventilation’s impact. With my HRV off, CO2 levels climbed to approximately 1,100 ppm. After running the HRV for 24 hours, levels dropped to around 700 ppm – much closer to the outdoor baseline of 400 ppm and well below ASHRAE’s recommended maximum of 1,000 ppm.

For VOC testing, I performed a controlled experiment:

1. Test 1: With HRV running at minimum speed, I sprayed glass cleaner into the return air grille
2. Test 2: One hour after shutting down the HRV, I repeated the same test

The results were striking. VOC levels remained significantly lower with the HRV running, and without ventilation, the chemical smell spread throughout the house almost immediately. This demonstrates why monitoring is crucial – without data, we can’t identify problems or verify that our solutions work.

Haven IAQ Monitoring Results

These tests were performed using the Haven IAQ Central Air Monitor, a duct-mounted, HVAC-integrated monitoring system that provides whole-home IAQ data with professional support.

Haven IAQ app readings with HRV at minimum speed after chemical introduction:

Haven IAQ app readings with HRV off before chemical introduction:

Haven IAQ app readings with HRV off after chemical introduction:

Here’s another experiment I performed using the Haven IAQ monitor to measure PM2.5 in the return air duct before the filter:

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A post shared by Gary McCreadie HVAC/R Tech/Business Owner (@hvacknowitall1)

Comparing Monitoring Approaches: Tabletop vs. In-Duct

Here’s valuable insight from Ben Reed on tabletop IAQ monitors:

Indoor air quality monitors come in various form factors – some sit on counters or tables, others are battery-powered and portable, while some mount to walls. Most measure particles and chemicals with varying degrees of accuracy and repeatability, though some include specialized sensors for specific gases or radon.

These monitors share one significant limitation: they only measure air in the room where they’re currently placed. While portable monitors can move between rooms, they can never measure all rooms simultaneously.

Additionally, most stationary or portable monitors use the same particle measurement technique: