Active and Passive Design

news, october 2019


Active and Passive Design


Active design. Passive design. What are these design principles and how do they impact the design-build community? Let’s take a look.


By Douglas Weinstein


The NextHaus Alliance
 

Active design. Passive design. What are these terms and how do they impact performance homes and the various design-build methodologies being utilized as part of an overall wellness platform, including air filtration and ventilation strategies?

Glad you asked!

We are going to be introducing air filtration/ventilation in the Fall issue of TD Magazine, a subject that will entail multiple articles to properly cover. Water purification discussions will follow, beginning in the Winter 2020 issue. I’d like to begin the overall discussion with an overview of two design-build philosophies – active and passive design. What are they and what do they mean. Once properly defined, you will then be able to evaluate air filtration/ventilation methodologies and how they impact each design principle.

We begin with definitions of active and passive design. In November, we’ll move the discussion forward, and in December the magazine will have a full-length article introducing advanced air filtration/ventilation principles. And their impact on the technology of the home.

active versus passive

Think of an active home design as the incorporation of active devices – air conditioners that cool, furnaces that heat, lights that switch on for illumination. You would even consider solar energy capture as an active process. Air filtration and water purification are active processes when mechanicals are introduced into the build.

When we think of passive design strategies, we think about taking advantage of nature itself to achieve some of the design goals in residential construction – siting the property to take advantage of sunlight, especially southern-facing glazing that captures indirect light throughout the daytime hours. Anticipating the height of summer and oppressive heat, shade trees can be incorporated into the design as a passive strategy in providing relief from the sun.

Natural ventilation is another passive design that reduces energy costs, while allowing fresh air to circulate. That being said, the first tenet of a passive design is to achieve air tightness in order to achieve optimal thermal performance. This principle is the bedrock of the Passive House movement called Passivhaus in Germany, where it was founded in the mid 1990s.

Passive homes feature significantly more insulation than the typical house, as well as thermal breaks to further prevent heat loss or gain. Triple-pane windows are exceedingly common in the design.

Keep in mind that an air-tight house can result in sick building syndrome if ventilation is not properly incorporated into the design. So at the end of the day, there appears to be a combination of active and passive methodologies being incorporated into today’s performance home design.

a healthier living environment

Which brings us back to clean air. Air filtration and ventilation. How it is achieved, how it is monitored, and how the results are delivered to the homeowner who wishes to see their home’s performance. We’ll wade in deeper next month as we explore the intersection of technology and design as it pertains to a healthy living environment.