Passive House is anything but passive
By Tim King
DON’T LET THE name fool you – there’s nothing passive about constructing a high performance building worthy of passive house certification.
In fact, achieving what many consider to be the pinnacle of building energy standards requires a substantial amount of activity – before, during and after construction is completed. The payoff, however, is great. By design, a building constructed to the current PHIUS+ 2015 energy standard will only use between 10-25% of the energy that a similar sized “codebuilt” building would require.
Here in Maine, with our cold winters and warm summers, the potential savings from reducing a home’s energy use by 75-90% represents a significant opportunity for homeowners.
Alan Gibson, principal of GO Logic in Belfast explains, “In standard-built construction, the cost of space heating makes up typically 75% of the total energy used by a home, with the remaining energy balance divided roughly evenly between the domestic hot water and plug loads. Reducing the space-heating demand will have greatest impact on the overall energy consumption and related costs.”
Gibson’s firm garnered both local and national attention after one of its most innovative projects was completed. The Belfast Cohousing & Ecovillage established an entire neighborhood of super insulated, energy efficient passive house buildings. Whereas it costs approximately $2,500 or more to heat a typical home in Maine (using 680 gallons of oil), the owners of the 1,500 sq. ft. homes at the Belfast Ecovillage spend $300 a year using only a few small, electric baseboard heating units, resulting in a savings of at least $2,000 or more a year.
It is the increasing number of these types of passive house success stories that are turning many skeptics into believers and making even the most otherwise old-fashioned municipalities in Maine take notice. When all is said and done, it seems that saving money is the one “green” benefit that can be universally accepted.
A passive house primer
PHIUS (Passive House Institute US), defines “passive building” as “a set of design principles used to attain a quantifiable and rigorous level of energy efficiency within a specific quantifiable comfort level.”
To attain these levels of efficiency and comfort, passive house buildings are designed and constructed using these (5) basic building-science principles:
Insulation - Abundant and continuous throughout the entire building.
Airtightness - Outside air stays out and conditioned air stays inside the building.
High-performance windows and doors are used to minimize heat loss and gains.
Ventilation - Mechanical and includes a balanced heat and moisture recovery system.
Placement - Buildings are positioned to maximize the solar energy potential of the sun.
It is this last point about the connection between solar energy and passive house that is often misinterpreted. “Although passive house projects may incorporate some basic solar principles in their design, these buildings are much different from the experimental, passive solar homes that were built in the past,” explains Michael Maines, a residential homes designer and passive house consultant located in Palermo.
“As a globally accepted standard for constructing lowenergy buildings—a standard that people in many different climates and cultures can agree upon—the passive house building energy standard provides an excellent path towards a much more efficient use of energy.”
The passive house boomerang
Ironically, the concepts that later led to the birth of passive house design were originally developed right here in North America. Unfortunately, the pioneering efforts of building scientists such as William Shurcliff and Wayne Schick during the 1970s were largely forgotten—and sometimes ridiculed— for their then-radical ideas about residential energy use.
After all, if fuel is cheap, abundant and harmless, why should anyone “waste” money by super-insulating their homes?
During the 1980s, as the U.S. economy boomed and enthusiasm around energy conservation efforts lost momentum, in Europe, passive house design and building techniques— along with the products and materials needed to achieve the desired performance measures—continued to be developed.
Across the pond, unlike here in North America, a shortage of physical space, fuel options and infrastructure have kept energy prices exceptionally high throughout Europe—so much so that many governments went so far as to not only encourage individuals, families and businesses to be more energy conscious, they mandated it.
As a result, many Europeans (and the companies that employed them) worked constantly to discover, develop and manufacture new technologies, materials and methods to achieve the maximum level of efficiency from every unit of energy that was either created or imported into their country.
At this time, two men, Dr. Wolfgang Feist (a German physicist) and Dr. Bo Adamson (a Swedish scientist) codeveloped the first passive house performance metric that documented exactly how a passive house building should perform. Based on these metrics, Feist went on to found the Passive House Institute (PHI) in Darmstadt, Germany, where the first passive house was built.
Fast forward to the present day, as high fuel prices and rising concerns about climate change have reemerged here in the U.S. Now a growing number of building scientists, architects, engineers, designers and builders are using the passive house standard as a guiding light for constructing new, comfortable, energy efficient homes and offices.
Today, passive house buildings of all sizes, styles, shapes and functions are sprouting up across the country and right in our own back yards. In every part of the state, Mainers are jumping on board and riding the cutting edge of a new and exciting trend.
What’s more, if this group of talented, determined, passive house devotees keep up their good work, Maine could find itself as a leader in high performance building category and worthy of its previously well-known national aphorism, “As goes Maine, so goes the nation.”
If it’s in 207, passivhausMAINE is in the house.
Here in Maine, the primary source of all things passive house is an organization called passivhausMAINE. The group, consisting of architects, engineers, designers and contractors, work together to inform, challenge and inspire each other to incorporate passive house design practices into their projects to help reduce the carbon footprint of the built environment throughout Maine.
Naomi Beal, the director of passivhausMAINE, is responsible for keeping the group connected and up-to-date on passive house developments from around the country and around the world. One of the trends she’s noticed is the recent emergence of a number of large multi-use and multifamily passive house projects.
Unlike single family, stand-alone homes (that may only provide benefits for the few people living there) larger projects such as The Friends School of Portland, located in Cumberland, and Bayside Anchor, a 45-unit mixed-use apartment building currently under construction in the Bayside neighborhood of Portland, not only bring more attention to the advantages of passive house design, they can also provide a sustainable foundation for addressing much larger issues in the community, such as early childhood education and affordable housing.
“Passive house design and construction practices have evolved from simply being a way for individuals and families to remove the financial burden of paying increasingly high energy costs into something much more,” says Beal. “These types of larger, municipal and commercial projects have the potential to impact the overall energy use of the entire state.”
Here in Maine, the best-known practitioners of passive house building capabilities include companies such as BRIBURN Architecture, Ecocor High Performance Buildings, GO Logic Architecture Construction, Kaplan Thompson Architects, Maine Passive House, Michael Maines Residential Design, Performance Building Supply, and Wright-Ryan Construction, among others.
It ain’t always easy to be passive
To paraphrase the late, great business icon and pitchman Frank Perdue’s catch phrase, “It takes a tough man to make a tender chicken,” one might say it takes an aggressive approach to build a passive house.
Around the globe, passive house construction has allowed millions of people to be able to afford to live in safe, comfortable, durable homes by removing the burden of paying incredibly high utility bills each month. For example, residential electricity rates for many European Union (EU) countries are more than double those typically found in the United States.
For very similar reasons, namely reducing the energy burden on low-income households--who pay more than three times as much as higher income households on utilities as a percentage of total income--several Maine building projects are underway or have recently been completed that incorporate passive house best practices. The most obvious reason for this trend could be to help conserve energy, thereby saving people money and perhaps the livability of our planet along the way.
But the reasons to consider passive house principles go much deeper than just energy efficiency for efficiency’s sake. Turns out that passive house buildings are healthier, more comfortable spaces for people to inhabit and the buildings themselves are more resilient, requiring less maintenance over their lifespans, too.
One benefit of living in a passive house that Mainers might find particularly interesting is the resiliency inherent in its design. Because of its superior insulation and airtight envelope, if the power goes out, a passive house will maintain a safe internal temperature of approximately 55°(F) indefinitely, regardless of outside temperatures – just like a giant Thermos® bottle.
Considering these factors, among others, it becomes clear that not only should passive house homes become an increasingly larger percentage of all residential construction projects – in some places and for some segments of our population, it may be the only way to meet our country’s ever-growing need for safe, decent and affordable housing.
A few examples of this are now happening right here in Maine.
Portland’s Bayside Anchor: A multi-use building with a singular focus.
The Bayside Anchor concept was first devised by Kaplan Thompson Architects and Wright-Ryan Construction back in 2013, with cooperation from the Portland Housing Authority and Avesta Housing.
The project received a significant boost after winning $250,000 through a national affordable housing design competition sponsored by Deutsche Bank and Enterprise Community Partners.
Built to the PHIUS+ low energy standard, the Bayside Anchor building, which is expected to be completed in November 2016, will include 45 apartment units, offices for the Portland Housing Authority and a Head Start Early Childhood Education program.
Amazingly, once completed, the bill to heat the entire 38,500 sq. ft. building is projected to be approximately $5,000 a year. Put another way, this is equivalent to an average heating cost per unit of $111/year. Yup, you read that right.
The project’s architect, Jesse Thompson, principal of Kaplan Thompson Architects in Portland, explains how this is possible. “The goal of creating a ‘passive’ building is to reduce the amount of energy needed for space heating as much as possible. We’ve designed Bayside Anchor in a way that essentially eliminates heating as a major concern for occupants. Instead, domestic hot water will drive much of the energy demand for the building.”
“Computer models can vary from what ends up happening in the real world. Should we see an exceptionally mild winter, heating costs could actually end up being lower. On the other hand, if a few residents decide to leave their windows open all winter, then our heating estimates can get blown away fairly quickly. It will be interesting to see what happens at the end of the first year of occupancy.” Thompson adds, “Regardless of whether or not the energy use ends up being higher than what our models have predicted, by design, Bayside Anchor will still deliver substantially lower heating costs than any other apartment building in Portland.”
To achieve this level of efficiency, as with all passive house buildings, Bayside Anchor will have much more insulation than a typical Maine home or apartment building (a 3” layer of polystyrene under the foundation, R-32 walls, R-50 roof deck). The structure will also feature a carefully sealed exterior building envelope, high-quality, triple glazed windows and a pair of energy-recovery ventilators on each floor to deliver pre-conditioned fresh air to each apartment.
While the amount of insulation going into Bayside Anchor may seem excessive when compared with a traditional home in Maine, those familiar with the passive house practice of super-insulating buildings may actually be surprised to see such relatively low R-values.
Better protection, simpler, by design
Another advantage that designers and builders have when creating an insulation strategy for a multi-unit building, such as Bayside Anchor, to passive house standards is that each individual unit is already well-insulated from outside weather conditions simply because of its proximity to the other units surrounding it.
More specifically, a large, multifamily building has proportionally much less outside exposed wall area than a stand-alone, single family home would—and less exposure means less opportunity for heat to escape.
Thompson explains, “When you isolate a single, middlefloor apartment inside Bayside Anchor, you can see that it only really has one outside wall, and you know that wall is 24 ft. long and 8 ft. tall. So, thermally, it’s easier [to sufficiently insulate each unit] because the ratio of living space to exterior walls is very small.”
In fact, the passive house concept was originally created for European multi-family buildings. The first recognized passive house building was a townhouse in Germany. Its middle unit had adjoining walls on each side that it shared with its neighbors, which meant they were never exposed to outside air.
A building with affordability built into it.
Village Centre in Brewer Another Maine housing development has also made headlines recently for its use of passive house energy standards. Village Centre in Brewer is a 48-unit housing complex that stands as prime example of how passive house energy performance can realistically be achieved within any sized budget.
Ben Walter, president of CWS Architects in Portland, and Wright-Ryan Construction both collaborated with Thornton Tomasetti, an engineering firm, for energy modeling help to determine the ideal building materials, fixtures and mechanical equipment to use in development.
According to published reports, achieving PHIUS+ certification resulted in a 3% increase in construction costs. However, the building’s residents will truly benefit as the building is also expected to self-regulate to maintain an even, comfortable temperature inside – without the use of a central heating system.
The price of performance
Much of the current research on passive house projects indicates that the incremental costs associated with attaining passive house performance is approximately 10% more than building an equivalent sized regular home.
This is only an estimate, which is heavily dependent on several factors such as the climate where the building is located, the building type, material availability and ease of access to qualified building professionals.
There is still some debate among building professionals over whether or not the energy savings that a passive house delivers its owner can adequately offset the cost of creating, transporting and installing more “stuff” in order to get it there. One way that passive house proponents are working to address these concerns is by developing new materials and new building practices that will deliver much better performance AND do so using fewer resources.
One Maine company has been at the forefront of doing just that.
A pre-fab passive house. Delivery included.
Ecocor, located in Searsmont, is a construction firm that designs, manufactures, delivers and assembles high performance buildings throughout North America. Earlier this year, the company announced that it had become the first company located outside of Europe to be certified as a Passive House component manufacturer.
Through its pre-fabricated, panelized building component approach, Ecocor offers some of the most energy efficient building technology available today. In a tightly controlled environment, constructed to the highest quality standards, Ecocor delivers passive house building components directly to the customer’s building site, ready for final assembly, in a fraction of the time it would normally take to accomplish in the traditional site-built way.
“Through our panelized construction process, we can produce components that will deliver the highest levels of building performance, at a price point that’s well within reach of anyone building a new custom home,” says Ecocor’s founder and technical director, Chris Corson.
This also means that over time, as more and more pieces of the passive house puzzle become available domestically to U.S. builders, the cost of these products and materials should also decrease.
Currently, the majority of high performing products, such as windows, doors and sealants, as well as the highly efficient heating and ventilation equipment, are manufactured in Europe and Asia. As a result, the products are typically sold at a premium price.
Ideally, as more companies like Ecocor continue to develop unique, high performing solutions (and more domestic manufacturers start building products capable of meeting these higher standards) the price gap between a passive house worthy product and a pretty good product will continue to shrink.
A shift in strategy. Minimize losses and maximize gains.
While the debate over the viability of widespread adoption of the passive house energy standard will likely continue for some time, one thing is clear: it has certainly helped to shift the way people now think about the relationship between buildings and energy use.
The traditional approach to residential home construction was simply to accept that a certain amount of heat loss (or gain) was inevitable. Builders would then equip the home with an oversized HVAC system that could replenish those losses or gains as quickly as possible – with little regard for how much energy was needed to do so.
The passive house concept focuses on building a structure that is capable of independently maintaining a fixed temperature inside the living area—no matter what the conditions are outside—with little to no energy use whatsoever.
While HVAC systems have improved their efficiency, it can still take a large amount of equipment and energy to replace cold and damp or hot and humid air to make a home more comfortable. Clearly, there’s some logic to the general notion that it takes a lot less energy to hold onto whatever you have than it does to create something new.
This is especially true when that something [heat energy] is in constant need of replenishing.
In the ancient Chinese treatise, The Art of War, Sun Tzu wrote that “the supreme art of war is to subdue the enemy without fighting.”
In its own way, a passive house building accomplishes this by defeating our shared enemy – unfavorable outside weather conditions – not by initiating a costly, energy-consuming battle inside the home. Instead, through the quiet strength found in passive resistance, the enemy is prevented from ever establishing a presence in the first place.
Imagine. Victory without conflict. Who could ask for anything more?
Tim King is a sustainability-minded freelance writer from Scarborough.
This article was reprinted from the fall 2016 issue of Green & Healthy Maine Homes. Subscribe today!