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SPRING 2015: PASSIVE HOUSES
The History of the Passive House Movement
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SPRING 2015: PASSIVE HOUSES
Source: Hollis Montessori School
Hollis Montessori School students interact with their building’s energy monitoring systems. It’s an important education taking place in an important building – the country's first certified passive independent school.
The Next Frontier: Passive Commercial ConstructionWhen it comes to Passive Houses, the rest of the world has generally been a step ahead of the U.S. Europe designed and built its first certified Passive House in 1990. The U.S. didn’t design and build its first until over a decade later, in 2003. In the years since, passive design has become increasingly popular throughout the country. There are now about 120 certified houses in the U.S. Not only does that number grow every year, it grows more rapidly every year. And if the number included houses built with passive design concepts but not fully certified, it would be even larger.
The U.S. may have a late start on passive houses, but it’s not far behind on the next big development: passive commercial construction. With the conceptof passive building proven in the residential sector,
designers are starting to experiment. Passive restaurants, hotels, office buildings and more are starting to appear throughout the world, including here in the U.S.
View Haus 5 is a great example, as the Seattle area’s first passive multifamily project. With a focus on indoor air quality and occupant comfort, the project is a showcase of luxurious and sustainable design. Units range in size from 1,100 to 1,700 square feet, featuring LED lighting throughout, multi-zone cooling and heating and zero-VOC paints.
Another example of a commercial application is the Glasswood Project, Portland, Oregon. The Glasswood Project was the country’s first commercial retrofit completed to Passive House standards, and features a full restaurant on the first floor and office/event space on the second. To complete the project, the designers tackled challenges like an energy-intensive, full-scale commercial kitchen.
Other notable examples in the U.S. include:
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The world’s first passive certified dental clinic, located in Roanoke, Virginia.
CAPACES Leadership Institute, Woodburn, Oregon. The country’s first passive certified office building.
Hollis Montessori School, Hollis, New Hampshire. The country’s first passive certifiedindependent school.
This list offers impressive highlights but is admittedly short. Over time it will grow. Soon, the U.S. will have a long list of passive commercial projects, contributing to a whole series of revolutionary projects across the globe. It’s a good time to think passive.
Warren Woods Ecological Field Station, Three Oaks, Michigan. The country’s first passive certified laboratory.
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SPRING 2015: PASSIVE HOUSES
David Peabody
Interview With an Architect: David Peabody, Peabody ArchitectsPeabody Architects (PA), Alexandria, Virginia, specializes in residential design and consulting. PA’s projects include sustainable new houses, alterations and additions. For PA, a sustainable home means a home designed thoughtfully and ethically. One of PA’s projects was the Bethesda Passive House – the 24th passive building certified in the U.S. and the first certified in the Washington, D.C. area. David Peabody has led PA since 1992 and has designed over 100 homes and additions. A LEED® AP for over a decade, Peabody was also one of the country’s first Certified Passive House Consultants. He feels strongly that architects should work to improve environmental issues.
How did you become interested in Passive House design?
It was a gradual process. In 2007, I became interested in [energy] modeling in real-time, but cost-wise and time-wise it didn’t really work to hire an engineer to model residential projects. An architect I knew said the Passive House program had very good Excel-based modeling software that you can really use as a design tool. I went to a Passive House Institute presentation and got involved in the program. It is about building extremely energy-efficient and healthy buildings affordably, and that is something I’m very interested in.
It seems like architects are being pulled in two directions: designing these simpler,energy-efficient buildings or designing something technologically complex. Whatare your thoughts on the matter?
From a standpoint of resilient design, we don’t want to make ourselves slaves to technology. Equipment with a lot of motors and pumps and computers, for example, is more vulnerable. While there will always be a certain degree of technology we need, it’s better to try to build something simpler, like an efficient envelope.
Simple design is also important from a standpoint of cost. Having a smaller mechanical system – for example mini-splits with just one compressor outside – is a lot cheaper than a traditional system. We’ve seen this with Passive Houses. They cost a little more to build but the result is that you don’t need a big mechanical system. In fact, a good bit of their expense is recouped because we can use a smaller system. So the simpler technology – focusing on building a better envelope – can bring costs down.
How important is HVAC to sustainable design, and what does that mean for the
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people you work with during the design process?Mitsubishi Electric Cooling & Heating
Photos courtesy of Peabody Architects
HVAC plays a really central role in sustainable design. It’s all about integrated design now. HVAC is not an ad hoc, separate thing. It used to be. In my generation, we told mechanical contractors, “Do what you want; I just don’t want to see the ducts.” But now architects are beginning to be interested in energy, making the HVAC subcontractor a critical player. When you’re designing really tight houses with a small cooling and heating demand, you need to work with someone who really knows what he’s doing. And you need to do this early on. If you don’t get the right equipment and the right-sized equipment for the job, you can get into all kinds of problems – like moisture buildup because of oversizedequipment short-cycling in summer months, for example.
What considerations go into selecting the HVAC system for a project? When you’veselected a multi-zone system, as you did in the Bethesda Passive House, whatleads to that decision?
It’s all about energy efficiency and the ability to dial systems down. For the Bethesda Passive House, there was the added piece of aesthetics. This was a high-end home that would be sold as a spec house. We didn’t know who the owner would be so we wanted all of the Passive House features to be invisible – for the house to function just like a standard house. So we used a fully ducted mini-split system integrated with the ERV ductwork.
Please describe a challenge you’ve faced that multi-zone products have helped solve.
This technology has been really helpful in retrofits and any kind of remodeling. With multi-zone, you’re running Freon lines rather than ducts. Replacing duct systems in an existing house can get very disruptive. Reusing those duct systems with new equipment can be very inefficient because they are often badly sealed and not properly sized for the new equipment. So small, ducted mini-splits distributed through the house is often the most efficient, comfortable and least disruptive choice.
Have you gotten any feedback from clients on the multi-zone systems that you’ve designed?
Clients rave about the comfort. They tell us often that they don’t have drafts, they don’t get cold spots – all of that is gone. Part of that is due to the improved building envelope and part is due to the mechanical system.
What advice would you give an architect who’s thinking about using multi-zone systems for the first time?
For residential architects, work with a mechanical contractor who has a good track record – who understands these systems – and work with him early on in the design process.
Also, any architects interested in the modeling software I mentioned earlier can contact the Passive House
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Institute or the Passive House Institute U.S. Either one will sell you their software.
Finally, please talk a little about your current projects.
We’re doing two Passive Houses, a net-zero house and what we hope will be the first Passive House retrofit of a historic structure in D.C. That last one is particularly challenging because we’re simultaneously trying to meet the requirements of both Passive House and D.C.’s Historic Preservation Review Board.
We’re also about to break ground on a modular Passive House in Prince George’s County. We’ve already gotten the precertification for Passive House and passed the blower door test. It’s an interesting project. Because it’s modular, we don’t have as much control as we usually do. But we’re using a mini-split system with a ceiling cassette downstairs and a ducted unit upstairs.
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SPRING 2015: PASSIVE HOUSES
Large, gorgeous homes like the Bethesda Passive House are changing the way we think of passive building.
Case Studies
The D.C. Area’s First Certified Passive House
The Washington, D.C. area’s first certified Passive House started as an idea. Architect David Peabody, president, Peabody Architects, Alexandria, Virginia, specializes in energy-efficient design. He arranged a team to build a spec Passive House. “We didn’t know who the owner would be, so the house had to look as normal as possible – the Passive House features as invisible as possible. We also knew we needed to build a high-end house to fit into the neighborhood,” said Peabody.
The team ultimately built the Bethesda Passive House, Bethesda, Maryland. It is a four-level, 4,400-square-footmarvel of design, engineering and construction. It
features classic architecture and style that blend in with the surrounding neighborhood. Inside its walls, however, one sees the passive building elements: ample insulation and correctly sized mechanical equipment (with appropriate capacities). Among that equipment is the S-Series multi-zone heat pump system from Mitsubishi Electric US, Inc. Cooling & Heating Division.
To specify an appropriate cooling and heating system, Peabody called in Dan Foley, president, Foley Mechanical, Inc., Lorton, Virginia. Foley suggested a multi-zone heat pump design with a ducted distribution system to help the house meet stringent Passive House criteria. Peabody, a Certified Passive House Consultant, agreed. “[Multi-zone systems] are pretty much the only approach anyone’s using for Passive Houses. A [multi-zone system] gives heating and cooling, and you can dial it down to give minimal loads. It’s the logical choice.”
The finished house sold quickly. “We were looking for a bigger house and were interested in a smaller carbon footprint,” said homeowner Martin Lindholm. The Bethesda Passive House, “located close to schools, shops and transportation, combined with the energy-efficient aspects, seemed like a great placeto live.”
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The Lindholms use their HVAC system throughout the year but “the bills don’t fluctuate much.” Lindholm said their cooling and heating cost averages $57/month. The U.S. Energy Information Administration’s most recent energy survey shows Maryland residents pay an average of $193/month for energy, making the Lindholms’ expenditure under one-third of their neighbors’. The Lindholms’ energy company says homes in the immediate area average $280/month, making the Bethesda Passive House’s energy costs almost one-fifth of its neighbors’. These numbers are all the more impressive given the indirect comparison; the Bethesda Passive House is considerably larger than the standard single-family home.
The indoor comfort level is also exceptional. Lindholm said, “The system does the job without you noticingit too much, which is really nice. It’s also quiet outside; we hear our neighbor’s system from three housesdown more than we hear ours.”
The Bethesda Passive House’s HVAC system offers smooth operation, year-round comfort and low environmental impact, making this is a success story for the ages. As the building industry’s collective attention turns toward passive construction, this story also serves as inspiration for the possible scale and elegance of passive building.
To learn more about the Bethesda Passive House, read the full case study here.
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“Our home generates enough energy to power our utility needsand enough extra [energy] to power an electric car for30,000 miles per year,” said owner Wes Parlee.
Making Zero-energy Building Possible in the Northeast
This winter may finally be over, but the next heating season is always around the corner. Residents of the eight-home Devens Green Zero Energy community, Devens, Massachusetts,aren’t worrying, though. Their homes staycomfortable throughout the year and don’t costanything in energy. In fact, they produce energy.
Wes Parlee is one such resident, living in a 1,912-square-foot custom home in the Devenscommunity. Parlee’s home cost him just $40,000more than traditionally built homes of the samesize. The investment will pay for itself in aboutsix years and continue to produce profit afterthat thanks to an annual average of $6,000 inenergy savings. This includes a $1,000 utilityrebate from the power company for the energy
his home feeds back into the grid.
To design his home, Parlee worked with Transformations, Inc., a Townsend, Massachusetts-based builder specializing in net-zero and net-positive communities. To counter the extremely cold New England winters,the team selected a Hyper-Heating INVERTER (H2i ) HVAC system from Mitsubishi Electric US, Inc. Cooling®
& Heating Division. The system’s high-performance twin rotary compressor allows for energy-efficient operation at extremely low ambient temperatures. The units put out 92 percent of their rated capacity at 5 degrees Fahrenheit and 58 percent at minus 13 degrees Fahrenheit.
Reflecting back on his previous home, Parlee is very pleased. “When we had the other house, we were spending all this money on oil to heat the home in winter,” said Parlee. “In this home, we do not have these bills, so in the winter, we keep the house at a very comfortable 71 degrees. The house has a consistent temperature.”
To learn more about the Devens Green DOE Challenge Home, read the full case study here.
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SPRING 2015: PASSIVE HOUSES
The Jung Passive House, Holly, Michigan, used Mitsubishi Electric M-Series equipment. Certified Passive House Consultant Michael Klinger said, “For this home, the annual primary energy calculation is 24.1 kBTU per square foot per year, far less than the 38 kBTU upper limit for Passive Houses.”
Mitsubishi Electric Celebrates Passive DesignKatrin Klingenberg, co-founder and executive director, Passive House Institute U.S., Chicago, discussed Mitsubishi Electric US, Inc. Cooling & Heating Division (Mitsubishi Electric) on her blog, saying: “Mitsubishi [Electric] has led the industry in efficiency ratings. Their mini-split systems are quickly becoming the most popular systems for Passive Homes in all of North America including the very cold climates.”
Mitsubishi Electric is honored to be a part of the passive building movement, and is currently the only cooling and heating manufacturer to sponsor the Passive House Alliance US. With an eye toward sustainability, Mitsubishi Electric consults on Passive House product development, supports regulatory efforts and building codes revisions, and offers products that enable passive design. One product line particularly well-suited to passive residential projects is the M-Series Heat Pump Systems. These systems offer year-round, high-efficiency cooling and heating. Their INVERTER-driven compressor and electric linear expansion valves offer higher efficiency with controlled power usage.
Success stories within the Mitsubishi Electric community abound. The Lema Passive House was the Chicago area’s first certified Passive House. The O’Neill Passive House was the nation’s first certified retrofit. PNC SmartHome Cleveland was the first home built in Cleveland without a furnace. All used M-Series equipment.
Mitsubishi Electric is honored, as well, to be involved in five of the country’s first certified commercial passive projects: a school, two office buildings, one laboratory and one multifamily building.
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