Jung Passive HouseChallenge: The Jungs wanted a traditional-style home that would meet rigorous Passive House standards.
To build a Passive House is to build a structure that meets the most rigorous building standards in the country. Builders and architects must consider superior insulation, extreme air tightness — while maintaining good indoor air quality — and strict cooling and heating loads.
Homeowners Kurt and Maura Jung of Holly, Mich., wanted their home to have a small ecological footprint. They liked the characteristics of Passive House building because it made them think about how much energy they would use. The Passive House design process is unlike that of other green building programs. Design teams run extensive energy modeling prior to construction to determine all the equipment and materials that will be used to achieve the required energy reduction. “We liked Passive House because the calculations are done before nailing any boards,” said Maura Jung.
Passive House Standards require extreme restrictions for heating and cooling as well as overall energy consumption. “For heating and cooling, this level of consumption is 90 percent less than typical two-by-four construction and 75 to 80 percent less for overall energy consumption,” said Michael Klinger, a licensed builder and certified Passive House consultant. Klinger is owner of Lansing, Mich.-based Energy Wise Homes, Inc., the builder of the Jungs’ new Passive House.
The Jungs enlisted Matthew O’Malia, AIA, a partner at GO Logic LLC, Belfast, Maine, as the architect on the project. Established in 2008, GO Logic focuses solely on passive building.
Passive features like super insulation and triple-glazed windows dramatically reduced the home’s heating and cooling loads, and the team began searching for an HVAC system that could accommodate these low loads without exceeding them. The team had originally planned to select a central air system but soon abandoned the idea: “The centralized system’s air handler did not have enough capacity to move the air through the ducted system, given the size of the house and resulting length of the duct runs,” O’Malia said. “The heating and cooling load of the house is low, so the systems required to meet that are also small. As a result, the low load system is not created to distribute air through long duct runs of a large house.”
To solve the duct challenges, the team selected a 23 SEER Hyper-Heating (H2i®) INVERTER-driven ductless system from Mitsubishi Electric US Cooling & Heating Division, Suwanee, Ga. (Mitsubishi Electric). “We liked this product because it was so simple and efficient,” Klinger said. “In high-performance buildings, you need to keep the mechanical system simple.”
Solution: A 23 SEER Mitsubishi Electric ductless system helped the home meet rigorous Passive House standards while keeping the house comfortable during harsh Michigan winters.
Construction was completed in March 2013, and the home achieved Passive House certification, in part due to the Mitsubishi Electric system. Operating at full capacity and at high efficiency down to 5 degrees Fahrenheit, the system helped the home achieve the necessary reductions in heating load, despite Michigan temperatures that vary widely through the year. O’Malia added, “The Midwest has 40 percent sun in winter and 60 percent in summer, which significantly affects solar heat gain. The heating and cooling system had to accommodate these swings.”
In fact, the high performance of the Mitsubishi Electric system helped the home far exceed minimum Passive House standards. The goal of any Passive House is to reduce energy consumption as much as possible so that it becomes realistic and affordable to energize the building almost entirely with renewable energy. “For this home,” Klinger added, “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.”
“The success of the home is due to great clients and good teamwork,” said Klinger. He predicts these tough standards are the future of good building practices. “It’s not a niche market anymore. By 2015 we will have the same air tightness standards everywhere. We are inching our way there.”