The Passive House: 80% less energy, will it happen in the U.S.?

“Maximize your gains, minimize your losses,” –these are the basic principles of the passive house approach according to the Chicago-based Passive House Alliance US (PHAUS), a nonprofit association of passive house professionals. A passive house project maximizes the energy efficiency of basic components inherent in all buildings; the roof, walls, windows, floors and utility systems. By minimizing energy losses, the mechanical system does not need to replenish the indoor environment as frequently, which in turn saves resources, operational costs and global warming-related pollution.

The system is based on a formula devised by physicist Dr. Wolfgang Feist in the 1990s at the Passivhaus Institute in Darmstadt, Germany. According to PHAUS, the passive house standard is the most stringent building energy standard in the world and buildings that meet the requirements must use 80 percent less energy than conventional counterparts while providing superior air quality and comfort.

A higher, net-zero standard

To minimize energy loss and reduce mechanical systems run time, the focal point of a passive house is insulation. A passive home’s super-insulated, airtight envelope traps conditioned air, preventing it from escaping. Walls are typically twice as thick as standard construction and are analyzed to allow for proper water and moisture management to make a long lasting, exceptionally healthy building.

Anyone who has owned an older home or lived in a drafty apartment understands how stopping outside air effects comfort and mechanical efficiency. From the early stages of design, passive building takes this into consideration, constructing and testing the envelope for industry-leading control of air leakage. Blower door testing is a mandatory technique added to assure high performance.

Passive home design also incorporates what can often be a weak link in the total envelope and first line of thermal defense: windows and doors. Passive building places significant emphasis on high performance windows, featuring triple-pane glass, air tightness and solar heat gain values.

Once a strong envelope is in place, the “lungs” of a passive home are the next critical component. Like a living, breathing organism, the lungs, consisting of an energy recovery ventilator (ERV), provide a constant supply of tempered, filtered fresh air and recycle indoor energy that’s typically found in exhaust air. The heat from outgoing stale air is transferred to the unconditioned incoming fresh air to be filtered. This step delivers a significant upgrade in indoor air quality and consistent comfort.

Going passive across the pond

In the Madison Park neighborhood, a Seattle suburb, Sloan and Jennifer Ritchie’s home is an example of what passive building can achieve. In one of the most humid cities in the country, the Ritchies aren’t sticky or uncomfortable; instead they’re surrounded by an airy 70 to 74 degrees on hottest day of summer and the coldest day of winter, using only a fraction of the energy consumed by a traditional house.

This seemingly too good to be true, environmentally responsible home is not an experiment or pipedream. In fact, more than 30,000 of such homes have already gone up in Europe and in Germany, an entire neighborhood with 5,000 of these super-insulated, low-energy homes is in the midst of construction.

With new Energy Performance and Indoor Environment in Buildings Regulation, the City of Brussels is rewriting building codes to reflect passive standards. Brussels has adopted the targets of the European EPBD Directive, calling for all buildings to be nearly zero energy buildings by the end of 2020, but the city is aiming for six years ahead of the slated deadline. Brussels’ new regulation is based on the Passive House Standard set by the International Passive House Association (IPHA).

The first passive house went up in the U.S. a decade ago in Urbana, Ill., but since only about 90 have been certified. What’s stopping the passive movement in the U.S?

One significant issue is cost. Higher fuel prices and energy taxes on European cities and towns offer a major incentive to embrace passive standards, whereas in the U.S., it could take a decade or more before energy savings offsets the estimated $30,000 extra in construction costs.

Proponents argue that the additional 5 to 20 percent in building costs will drop once construction across the U.S. reaches critical mass and more American manufacturers are on board. Some signs show this could be happening sooner than later. More than 1,000 architects, builders and energy consultants have received passive-house training and manufacturers such as Minnesota-based Marvin Windows & Doors are now making products that meet passive certification standards.

Cost is not the only hurdle preventing the passive movement from really taking off. Not only is getting certification tricky, no two passive houses are likely to be built to the exact same specifications. Hundreds of variables from location and climate to architectural design and number of occupants all play a role.

But the end goal, even if it comes slowly in the U.S., is to build better –to look at the home as a living, breathing being that serves occupants more harmoniously.