125 Haus is an ultra green home in Park City, UT, and is likely the most energy efficient home in the entire state. The house was built by University of Utah architecture professor Jörg Rügemer (owner of ARJ), who spent about a year refining the sustainable and energy efficient strategies for his home, which has been designed according to German Passivhaus standards. With super thick and insulated walls, a compact layout and smart use of heating and lighting systems, the 125 Haus is 90% more efficient than a standard home. Read on to see pictures of our private tour of this modern mountain home.
Hailing from Germany, Rügemer was accustomed to a higher standard of efficient design for homes and planned to one day build the house of his dreams here in the US for his family. He set out to build an incredibly high performing home at market rate to prove that it was possible. After locating a good lot in Park City, UT he spent over a year designing and redesigning the 3 bedroom home to achieve the optimum efficiency for the right price. Working with Garbett Homes and radiant heating specialists he was able to come up with a design that relied on a high performance envelope and required only a small amount of energy to heat even in the dead of winter.
The 2,400 sq ft home is three stories with a garage and studio on the basement floor. The ground floor features a large living room and the kitchen and dining room, while the upstairs holds three bedrooms, two bathrooms, built-in storage and the mechanical room. A staircase sits in the center of the house, divides the space and acts as a light well and natural ventilation stack chimney to move air throughout the house. The decor is clean, simple and very German – in fact, most of the appliances actually come from Germany and compactly fit into the kitchen.
Solar passive design is one of the keys to the home’s successful design and energy efficiency strategy. Oriented to the south, large windows soak up as much sunlight as possible and a concrete floor serves as thermal mass to distribute heat through out the house. Small window shades block sun during the summer, but no air conditioning is required – only natural ventilation is needed for cooling. Radiant floors, sunlight, and HRV provide most of the heat needed for the house, but on cold days the efficient fireplace in the living room may need to be turned on. The R-60 walls are super thick achieved using both 11 inches of blown-in insulation and a 4-in thick insulation wrap around the exterior. 125 Haus was designed in accordance with Passivhaus standards although it won’t be able to achieve certification because of a few technicalities.
Passive solar, a tight and heavily insulated envelope, and energy efficient systems are key to the home’s performance. On top of that Rügemer has the entire house wired to monitor systems and temperatures. Accessed from a computer of the home’s tv in the living room, Rügemer can see how the home’s temperature and energy use varies over time. Even though he analyzed almost every scenario he could think of during the design phase, he’s learned even more since living in the home. For instance, he now knows he should have added more thermal mass above the garage to absorb heat from the cars after they return home in the evening. He also knows the master bathroom is colder than it should be. This is the sort of knowledge that comes after experience the space for months and watching his readings. Rügemer plans to take this knowledge and apply it to his other projects and hopes that the 125 Haus can serve as a model for more affordable and higher performing homes in Utah and throughout the country.
Images ©Bridgette Meinhold