Produce PassivHaus in ArchiCAD

Produce PassivHaus in ArchiCAD

Kaplan Thompson ArchitectsWith six projects featured on the recent NESEA Open House Tour, Portland, ME based Kaplan Thompson Architects (KTA) is fulfilling its mission to create and design buildings that are “Beautiful, Attainable, Sustainable”. We’ve chosen to highlight two of the projects KTA is designing, in light of the focus on sustainability this week’s Greenbuild show in Toronto provides. These two unique residential designs place high demands on ArchiCAD.

Harborview Townhouse

Harborview Townhouse

KTA is now in the early phases of permitting for a seven-unit condo project in Portland, ME (Harborview Townhouse) and is supervising the build on a very unique single family home in the mountain regions of Virginia. (Earthship Farmstead). Both are two unique projects designed to obtain LEED certification and Net Zero Energy use and Passive house Certification.

The internationally-recognized green building certification known as LEED, or Leadership in Energy and Environmental Design was first developed by the U.S. Green Building Council (USGBC) in March 2000. Building owners and operators can find through LEED a workable framework to identify and implement areas to apply green building design, construction, operations and maintenance solutions. Net-Zero Energy Buildings can be independent from an energy grid supply, whether harvested on-site through solar or wind energy. The building’s overall use of energy is reduced through efficient HVAC and Lighting technologies.

The Passive House concept represents today’s highest energy standard with the promise of slashing the heating energy consumption of buildings by an amazing 90%. In order for a home to achieve Passive House standards, it must be a very well-insulated, virtually air-tight building that is primarily heated by passive solar gain and by internal gains from people or electrical equipment from inside the building. Energy losses are minimized. Any remaining heat demand is provided by an extremely small source. Avoidance of heat gain through shading and window orientation also helps to limit any cooling load, which is similarly minimized. An energy recovery ventilator provides a constant, balanced fresh air supply.

Earthship Farmstead

LEED certification is commonly sought in sustainable architecture, where Passive House is not. Passive House requires extremely strict adherence to energy use, and LEED provides a focus on all elements of sustainability. “We realize that aiming for simultaneous LEED and Passive House certification is a significant undertaking, especially when you consider that only twelve homes built in the United States have managed to be Passive House certified,” explained Thompson. “A LEED silver certification can still have poor energy use.”

Though greatly varying in their design demands and end use, the successful process applied to each build can be attributed in part to ArchiCAD’s flexibility, according to KTA principal architect, Jesse Thompson.

“We’ve become proficient in using ArchiCAD to complete Net Zero, such as our high publicized Bright Built Barn. As we move forward and fine tune our process to achieve the even more rigorous Passive House standards, we are able to analyze the project and do it for less without hiring an outside firm. We’re making it work on projects that are 2,000 sq ft houses and it is still working. We’re making it accessible – because of our ability to use the software we’ve already been using. The high end projects give you the room to learn, but it is possible to use it in a targeted way to get going on smaller projects.”

Harborview Townhouse

The Harborview Townhouse project provides an example of how KTA has used ArchiCAD to design a multi-family dwelling. Thompson says the seven-unit condominium complex’s design is aimed at achieving a building that can be heated with the power equal to that used by a single hair dryer – in other words, extremely energy efficient. Going beyond LEED certification, KTA is working toward Passive House certification on the multi-family residence. That required an efficient design process as well.

Even though situated in a cold Northeastern climate, Harborview is built so efficiently that heating costs are estimated at $300 to $400 annually per unit. Thompson says the added efficiency didn’t add to the bottom line, “We’re able to put more efficient systems in, without it being more expensive to build. That is just not possible without the early on manipulation we can perform with ArchiCAD. Granted, it matters how the builder builds it, but we are confident in the model we’ve created and the quality standard we’ve called for.”

Harbor View is a large enough building to have a few hundred window units – an energy vulnerable element in any home or residence. KTA took advantage of ArchiCAD by creating a window schedule for each unit. Then the architects were able to pull all the windows out and enter them into the energy model. “What we used to do was run all the calculations after the design was done, but not be able to change the results. Now that we’ve modeled everything in full 3D we can analyze energy use at the same time the developer is analyzing cost,” explained Thompson,  “our work proceeded three times faster. As with many of our energy efficient projects – especially those we hope to achieve Passive House Certification we need to remove unnecessary steps and avoid surprises. Using ArchiCAD made our process more streamlined.”

With such a complex building, having the window schedule to plug into the design made it possible to modify window units and determine how those changes affect cost before committing to changes. “It changes the design perspective, from what can we afford to what is the best building we can create. ArchiCAD as a tool is helping us design better and smarter.”

KTA works from a list of every window in the building – inside ArchiCAD’s automatic scheduling, to better organize it. Windows can be swapped out or moved and not lost. When KTA’s developer wants to know how much it will cost he’s able to run the window schedules and see how the cost is affected on a unit by unit basis. Not only is it critical to the pricing, it has provided the developers with an affordable sales tool, adds Thompson. “Rendering 3D in ArchiCAD gives us the opportunity to demonstrate the condos complete with interior and exterior perspectives before they buy. The accurate floor plans have helped prospective buyers visualize the section and since we can pull these images off the construction documents it saves the developer from having to hire a separate sales person.”

Earthship Farmstead

Earthship Farmstead

Nestled into the hillside in a mountain region of Virginia, KTA is applying similar techniques from ArchiCAD and working toward achieving the strict Passive House certification for a farm house. The clients stated they wanted the home to be Net-zero energy (or energy positive!), Passivhaus and LEED certified. Having had previous experience with Net-Zero homes would serve KTA well on this project. “Earthship Farmstead was an entirely different project, born out of a client request to have a net zero home, off-grid, with sheep grazing on their roof,” explained Thompson.

KTA designed and is now overseeing the construction of the farmhouse so that it is built to the German PassivHaus standard. The complicated design includes a steel frame and concrete roof. The full steel frame was modeled in ArchiCAD, there are complex angles and miters and all the details were built inside ArchiCAD to demonstrate to everyone on the project how to get from concept to full final built project. Thompson says the use of ArchiCAD was critical to the success of the project.

Earthship Farmstead

“Since there’s so much weight on the top of the home, we had to design it around a steel frame. But in keeping with Passive House standards, we had to make sure that the steel – which conducts cold – never had an opportunity to compromise the airtight nature of the home. We have very high tech thermal breaks in the design – especially the shade patio – there are steel columns there that hold it up, but they cannot connect to anything inside because of the risk of cold conduction. Put simply, the only way to get this built was to design it in ArchiCAD.”

KTA situated the house directly in the hillside, taking care to adjust the floor plan so it would conform to the contours of the field. Working with the location, an eastward facing slope, the firm chose to extend the living and dining room areas out onto the crown of the hill – to better take advantage of winter sunshine for natural heating.