When you walk into a conference room and instantly feel that stale, heavy air, it’s the ventilation system that you should blame.
Indoor air can quickly go stale. People exhale carbon dioxide, furniture and cleaning products release chemicals, and moisture builds up from simply breathing and working. Without fresh outdoor air, these pollutants concentrate. That’s why every building needs a steady flow of outdoor air—it’s like giving the building lungs. It keeps oxygen levels healthy and helps carry away the contaminants we produce indoors.
The “stuffiness” you sense in many offices or schools comes from too little fresh air and too much humidity. These two factors have more to do with our comfort, health, and even productivity than we realize. A study led by Harvard University has shown that improved ventilation positively affected cognitive function leading to significantly better decision-making performance among the participants in the study.
Past efforts to conserve energy in the U.S. included reducing ventilation rates so buildings didn’t have to bring in as much fresh air, which then needed to be cooled, heated, and dehumidified. However, as the COVID-19 pandemic demonstrated, ventilation and fresh air are critical elements of healthy buildings.
That’s why the latest energy efficiency standards for commercial buildings are making a big change: new buildings will need to use specialized air conditioning systems that bring in outdoor air through something called a Dedicated Outdoor Air System, or DOAS, a key component of healthy building equipment.
How We Do It Today—and Why It’s Inefficient
In most buildings today, the heating and cooling system handles everything: temperature, humidity, and ventilation. That sounds simple, but it’s actually very wasteful.
When hot, humid outdoor air comes in, a typical air conditioner has to overcool it by bringing the temperature way down to squeeze the moisture out—and then reheat it so it doesn’t feel like an icebox. That double process uses a lot of energy. As a result, more than half of a building’s cooling energy is spent just on removing humidity, not lowering the temperature.
The Future: Dedicated Outdoor Air Systems
Now, imagine if ventilation had its own dedicated system, one that could precisely manage outdoor air and humidity without overworking the rest of the HVAC equipment. That’s what a DOAS does.
A DOAS brings in fresh outdoor air, filters it, and conditions it to a comfortable state before sending it into the building. It often includes an energy-recovery system, which captures heat or coolness from the air leaving the building and transfers it to the incoming air. Think of it as preheating or precooling the air for free. The result is cleaner, drier, more comfortable air and much lower energy use.
Why Humidity Matters
Here’s the secret: humidity has more to do with our comfort than temperature. High humidity makes warm air feel hotter and sticky; low humidity makes it feel crisp and refreshing. By controlling humidity more intelligently, buildings can raise their thermostats a few degrees while still feeling just as comfortable and saving energy without sacrificing comfort.
The Nobel Prize and Air You Breathe
In October 2025, the Nobel Prize in Chemistry was awarded to the researchers who developed metal-organic frameworks (MOFs,) a class of materials with a magical ability to trap molecules of water or carbon dioxide out of the air. More importantly, once trapped, the molecules can be released with very little energy.
What does this mean for you and the air you breathe? It hints at a future where air conditioners don’t just dry and filter outdoor air—they extract moisture more intelligently, using materials that do heavy lifting at the molecular level. MOFs could dramatically reduce the energy needed to remove humidity by trapping and releasing the water vapor before it reaches cooling coils. And that’s exactly what my company, Transaera, an MIT spin-off that bet early on the promise of MOFs, is doing: using these cutting-edge materials and new system designs to lower the energy use of air conditioners while delivering balanced, fresh, dry air.
So the next time you step into a building that feels instantly fresh, light, and comfortable, you might have a DOAS and the Nobel-winning scientists to thank. It’s the quiet comfort revolution making indoor air not just cleaner, but cooler in every sense of the word.
Sorin Grama is the founder of Transaera, a Greentown member company.
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