Lessons Learned in Indoor Air Quality in 2019

Every building is an opportunity to improve people’s health and impact on the natural world


This past summer, much of the Pacific Northwest escaped the wildfire season unscathed. It was a welcome break from what has become a new normal of hazy skies and poor air quality advisories throughout the Northwest in recent years.

Yet in southern Oregon, where the Milepost 97 fire burned more than 13,000 acres in late July and early August, four counties were under air quality advisories for numerous days. During the fire, Barbara and Bill Steele, Demeter-certified Biodynamic® farmers, winemakers and owners of Cowhorn Vineyard & Garden, experienced dark skies at their 117-acre farm in Jacksonville, Oregon. Yet inside their modern tasting room, they and their customers were breathing easy.

Healthy Indoor Air Quality: An Added Benefit of Zero Energy

Completed in the spring of 2016, the Tasting Room at Cowhorn Vineyard & Garden is the world’s first tasting room to achieve the Living Building Challenge, which is known as the world’s most rigorous third-party green building rating system. Inside the naturally bright space, the indoor air quality is better than the outside air quality on any given day. This is definitely not the norm. Here’s how we addressed indoor air quality and energy efficiency at Cowhorn as well as with numerous other projects for nearly two decades.

Addressing Air Leakage

As air leaks through buildings, it deposits and picks up micropollutants such as pollens and dust accumulated in the walls, roofs, and floors. Wildfires and industrial air pollution aside, our vehicles emit toxic fumes and particulates, which can easily drift into buildings through air leaks. Our gas cooking ranges and the oils we burn when we cook produce indoor pollution. In the absence of continuous filtered ventilation, these pollutants are unlikely to find their way out.

Airtight building envelopes (floors, roofs, and walls) can nearly eliminate air leakage and the drifting of toxins. Using air-quality sensors on some of our Zero Energy projects to test indoor air relative to outdoor air, we’ve learned we can achieve indoor air quality that’s 30 percent cleaner than outdoor air. We do this by combining an airtight envelope with a well-planned and filtered ventilation system. An airtight home is an extremely energy-efficient home. This
is why much of the world, including many European countries and China, are adopting advanced building codes that require this type of construction. Many are requiring that new buildings meet the Passive House Standard — a super-insulated, airtight, and expertly ventilated design-build method that results in buildings that are at least 10 times tighter than a typical building constructed to meet U.S. code.

Improving Ventilation

Toxic combustion equipment inside buildings, such as furnaces, hot water heaters, gas ranges, and wood stoves all contribute pollutants to the air, both inside our homes and out. Gas cooktops emit nitrogen dioxide, among a long list of other hazardous gases, and have directly been correlated to neurological development issues in early childhood.

All-electric homes eliminate a majority of these toxins and also future-proof the carbon footprint of a building, as many utilities have set a goal
to transition to all renewable power by 2050. However, ventilation is always important – even in an all-electric home.

Once a building envelope is airtight, we recommend installing a fully dedicated heat recovery ventilator (HRV), which acts like a building’s lung. A HRV is a building-scale ventilation system that both filters and conditions incoming air by exchanging heat with the outgoing air. In residential buildings, the best practice is to install the system to provide continuous air to the bedrooms and extract air from the bathrooms and kitchen continuously. Efficient HRVs use less energy than a 40w light bulb and lose less than 10 percent of the air temperature even on the coldest days.

Choosing Healthy Building Materials

The EPA has been regulating the same chemicals since 1976, and we know that list reflects less than two percent of the harmful chemicals used in building and furniture materials. If you’re allergic to a certain ingredient such as peanuts, food labels can save your life. That’s not the case with most manufactured products.

Healthy material selection is a vital part of all Green Hammer projects. Before we recommend a building material for a project, we research their ingredients and check to see if they meet stringent responsible management and manufacturing practices. When building at Cowhorn Vineyard & Garden, for example, we extensively verified every ingredient for more than 1,500 building materials. Many materials, such as cork, wood, glass, and metal, were selected for their simplicity and healthy ingredients. Yet, for materials such as paint and countertops, we had to work diligently to find ingredient lists.

Bottom Line

As more cities and states set stringent climate action goals, they are looking to their buildings to help them meet carbon reduction goals. High- performance buildings that incorporate energy- saving design features, like airtight envelopes and ventilation systems, will drastically reduce carbon emissions while improving people’s health and wellbeing.

Stephen Aiguier is the Founder and President of Green Hammer Design Build in Portland, Oregon. To learn more, please visit www.greenhammer.com.