Can “Green” Buildings have Negative Health Effects?
A recent blog on TheHill.com carried the headline “green” buildings could harm your health. This post was circulated widely via the American Society for Heating, Refrigerating and Air-Conditioning Engineers weekly e-newsletter.
Such headlines are at best misleading. Before the wrong information spreads too widely, we should state some basic facts about the blog’s topics: an Institute of Medicine report and green buildings.
Fact 1: The report does not focus on “green buildings”
The report in question addresses the impact of climate change on human health in indoor environments. Among other issues, it identifies buildings with tighter, more energy efficient envelopes (i.e., the roof, exterior walls and windows) as a particular concern. Contrary to what the blog implies, “green” buildings are not discussed in the report.
Fact 2: Green buildings create healthy environments
Green buildings are widely associated with healthy environments as well as energy efficiency. Saying a green building could harm your health is like calling the Taj Mahal a banality of architecture.
Fact 3: Tight building envelope does not equal poor ventilation
Energy efficient buildings with tight envelopes do not necessarily have lower ventilation rates than other code-compliant buildings. They may, in fact, be higher.
The purpose of a tight building envelope is to decrease the amount of unintended air entering and exiting a building. The amount of intended ventilation may need to be increased as a result. A good engineer knows this and will make sure the building is ventilated to current standards.
Fact 4: There’s no need to panic
The report is a proactive measure to counter potential problems, not a warning of impending doom. It raises a valid point in that increased tightness in construction, especially in residential buildings, will probably necessitate a reconsideration of ventilation standards.
In fact, the DOE’s Weatherization Assistance Program for residences acknowledges this issue, and now requires that all homes weatherized after January 1, 2012, must meet the most recent minimum ventilation standards.
A ventilation issue was encountered in the late 70s and 80s when code-required commercial building ventilation rates were drastically decreased to levels two- to four-times lower than today in an effort to decrease energy use. This caused many instances of what was dubbed "sick building syndrome" where building occupants got sick at much higher rates than usual in these under-ventilated buildings.
The issue of buildings and health effects has been studied in detail for many years, and it is well known that energy efficient buildings are not necessarily “healthy.” Ventilation is clearly one area where the two objectives are at odds. Other areas such as daylighting and moisture control are well aligned. These issues simply underscore the need for an integrative design approach to building projects, which enables designers to achieve energy savings as well as many other benefits.
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