The Empowerhouse was one of the most interesting entries in the 2011 Solar Decathlon; It was restrained, economical and had big plans for the future. Students from Parsons The New School of Design and Stevens Institute of Technology built it to Passivhaus standards and then went on to win the affordability contest at the Decathlon, "demolishing the myth of the Passivhaus premium". The principles followed were simple:
These include high levels of insulation, airtight construction, high-performance windows and doors, minimized thermal bridging, and windows and shading placed to control solar heat gain.
The real important difference in the Empowerhouse was the long-term plan to use it as a real house after the show in the Deanwood neighbourhood of Washington. In 2010 I wrote about my concerns that real-world applications usually lost out in the Decathlon to the high tech gizmo green entries.
Here, Parsons The New School's team is going one step further and actually building it for the real world. That is a bigger challenge than the Decathlon. It should be interesting to watch.
Now, two years later, they have finally done it, and have cut the ribbon on the relocated and expanded Empowerhouse. It's now a 2700 square foot semi-detached home built with Habitat for Humanity.
This new model for affordable housing advances Habitat for Humanity’s current building practices with high-performance, energy-efficient technologies. It will provide its residents with an ability to produce all of the energy needs, reduce their water usage, and grow food. These benefits will not only save the homeowners money, but will empower them to create a more sustainable lifestyle. Empowerhouse embodies Habitat for Humanity’s vision that all people deserve safe and comfortable homes.
The Passivhaus design will save a lot of money for the occupants, without a whole lot of green gizmo technology:
Empowerhouse will require up to 90 percent less energy for heating and cooling compared to an ordinary home. This is accomplished by optimizing the building envelope so that it is very well-insulated and virtually air-tight; incorporating energy-efficient appliances; maximizing natural light with well-placed windows and shading; and installing micro-mechanical and smart electrical systems that use approximately the same amount of power as a hair dryer. These technologies minimize the need for solar energy, and the Empowerhouse had one of the smallest photovoltaic arrays (4.2 kilowatt) in the competition.
That is the beauty of the Passivhaus concept; by using a lot of insulation and sealing it tightly, with careful siting to minimize solar gain when you don't want it and max it out when you do, it doesn't take much energy at all to run the house. Heating and cooling is provided by a small mini-split heat pump; the highest tech item in the home is the ERV. (energy recovery ventilator). The photovoltaics on the roof feed into the city grid, and if the house is managed properly, can cover all its energy needs.
The plan is interesting too;
The front porch is a crucial extension of the home into the neighborhood that encourages a public presence on the street. Additionally, a large kitchen for family cooking is an essential focal point of the home. The open plan creates an intimate environment for entertaining and family interaction, and is flexible to the needs of the residents. The plan allows for a few adaptable features such as a kitchen island that transforms into a large dining table. The back porch is calibrated to maximize winter sunlight into the living areas, minimizing the amount of heat needed, and features planters for growing food.
I don't know what happens with most Solar Decathlon entries; perhaps they are shipped back and parked behind the schools that built them, or are parked in some high tech trailer park somewhere. The Empowerhouse is different. It was not particularly flashy or high tech; it is no surprise that it only came in 13th overall in the competition. (see Matt Hickman's coverage on MNN here) It was designed for the real world and has landed in it with a bang.