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Ten Misconceptions About the Passive House Standard
Monte Paulsen / Green Building Advisor / September 24, 2013
Arguments against the Passive House standard are based on misunderstandings
I’m a small building energy modeler, and the tools of my trade are airtightness, insulation, window placement, and heat-recovery ventilation. These are also the tools of the international Passive House standard (known in Europe as the Passivhaus standard). And yet, almost every week, some veteran home builder patiently schools me as to why these building performance strategies — or Passive House requirements — are a waste of time or money.
I have compiled the most frequently cited arguments I hear; let’s call them “Ten reasons not to build a Passive House.”
Myth #1: Too expensive
I hear this almost every time I hand out my business card. It doesn’t seem to matter whether I’m listening to the builder of a $4 million luxury home or a $400,000 townhouse; nearly everyone assumes a Passive House costs more.
The truth is counterintuitive: If you include operating costs in the equation, Passive House emerges as the most affordable way to construct any building.
Here’s the math: Passive House walls and windows cost more than code construction, while Passive House heating systems cost less. On balance, Passive House construction costs up to 10% more than code. (Costs for land, carrying and marketing remain unchanged.) Upon completion, Passive House buildings require an average of 90% less heating energy than code buildings.
Amortize the one-time construction premium over the life of a mortgage, subtract the annual savings on utility bills, and most Passive House owners save money every single year.
This inherent affordability is no accident. The Passive House standard evolved from research experiments in which European scientists sought to calculate a balance point below which the installation of more insulation provided a measurable return on investment, and above which more insulation returned no economic benefit. This economic “sweet spot” is what defines the Passive House standard, as well was what distinguishes Passive House from most green building standards.