Humans spend about 90 percent of life indoors, which means nearly every breath we take happens inside a building. Yet while we scrutinize every ingredient in our food and care deeply about the purity of our oceans and forests, most of us overlook the quality of the air we breathe for the majority of our lives.
That indoor environment profoundly affects our health, cognition, and well- being. For years, carbon dioxide was seen only as a harmless indicator of poor ventilation. Now, we know it’s a harmful pollutant that dulls concentration and decision-making. Studies have shown measurable drops in focus and reasoning when CO₂ levels reach amounts common in everyday buildings. And it’s not just carbon dioxide. Pollutants such as dust, pollen, and volatile organic compounds have been proven to slow response times even in young, healthy office workers.
The reverse is also true: When indoor air quality improves, so do people. In a landmark 2016 study, Dr. Joseph Allen and colleagues at the Harvard TH Chan School of Public Health found that workers in “Green” buildings performed 61 percent better on cognitive tests. In “Green+” buildings — with both low volatile organic compounds and enhanced ventilation — their scores were more than double those of workers in conventional buildings, when tested for strategic thinking, crisis response, and information usage.
Yet most buildings are not designed for optimal air quality. Air leaks through gaps, crawl spaces, and wall cavities, carrying pollen, wildfire smoke, car exhaust, humidity, and mold spores. To save energy, most HVAC systems then recirculate this stale air, concentrating CO₂ and volatile organic compounds from furniture, paint, and finishes. We end up breathing a cocktail of indoor pollutants, day and night.
Passive House changes that. Originally developed as one of the most sustainable building standards in the world, it has turned out to be one of the healthiest too. Passive Houses are built with exceptional airtightness and continuous insulation, eliminating the uncontrolled infiltration that brings pollutants indoors. They use heat-recovery ventilation to supply a constant flow of filtered, fresh outdoor air while capturing heat (or coolness) from exhaust air — so comfort and efficiency work hand in hand. High-performance filters remove fine particles, pollen, and even wildfire smoke.
The result aligns perfectly with what Harvard’s research defines as optimal: steady temperature, clean air, low CO₂, and consistent ventilation. People who live in Passive Houses report fewer allergies, better sleep, reduced respiratory symptoms, and improved focus and mental clarity. The comfort is constant, the air is fresh, and the health benefits are measurable.
Build a Passive House. Or renovate your existing house to Passive House standards.
It will make you healthier, happier, and more productive. And, yes, it’s good for the planet too.
Tim Gorter, AIA, NCARB is a licensed, Passive House–certified architect with more than 25 years of designing and delivering residential, commercial, and institutional projects. He founded Tim Gorter Architects in 2010. Architecturally Speaking is written by members of the American Institute of Architects’ Santa Barbara chapter.
