We were approached by our clients with a simple request, "We want a house where our sheep can graze on our roof." No problem!
Our clients were looking to build a farmstead in the Virginia mountains that would be as self-sufficient as possible. Net-zero energy (or energy positive!), Passivhaus and LEED for Homes were the stated performance goals. Our previous experience with Net-Zero homes would serve us well on this project.
We nestled the house in the hillside, bending the floor plan to carefully fit the contours of the field. The slope of the hill faced east, however, and we knew we would need to capture as much winter sun as we could to naturally heat the home, so we extended the living and dining room out onto the crown of the hill, raising a broad bank of carefully shaded windows to the south to scoop in the sun.
The clients were looking for a stylish, soft, natural modernism for their house, and we chose a palette of white cedar shingles, local fieldstone, and quiet metal accents to harmonize with the colors and tone of the surrounding mountains.
Local, healthy and sustainable materials were specified throughout the project. As parents of young children, our clients were rightly nervous about modern industrialized building products, so we set strict limits on Formaldehydes and VOCs. The building is also insulated with cellulose insulation and water-blown EPS foam (two of the most environmentally friendly insulating product on the market).
All flooring is local white oak, the cabinetry is Virginia black walnut, and American Clay Paint was used throughout the project.
The property is amply supplied by well water, but water pumping can be a large energy draw, so all pumps and fixtures were carefully evaluated to ensure that the water use wouldn't over-tax the energy systems.
The landscape design carefully considered water use as well, including a large cistern that stores and reuses all water from the roof.
The house has been designed to sit within the natural landscape, with an extensive green roof and native plantings. The farm fields spread up to the house itself, carefully delineated with gentle low stone walls of local Catawba stone that contain a broad stone patio on the private side of the house.
The house is designed to meet the most rigorous energy standard in the world: the German Passivhaus Building Energy Standard. See: http://passivehouse.us/ & http://www.passiv.de/
The house uses 90% less energy for heating than a typical house, and can be heated on the coldest night of the winter with the energy of two hairdryers.
It is a tough, easy to maintain, comfortable and extremely cost effective house to live in (estimated $500 / year total to heat).
The building were built with R-30 slab, R-30 walls and R-40 to R-60 roofs. The windows and doors are by Makrowin (EAS USA: http://eas-usa.com/), with triple glazing and thermally broken frames.
The complete heating and cooling system is a tiny 1 1/2 ton heat pump system by Mitsubishi with fresh air continuously supplied to the living spaces through an Energy Recovery Ventilator by Zehnder (http://www.zehnderamerica.com/products/comfounit_home.asp)
There is a 12 kW photovoltaic array on the barn supplying all the energy the farm needs, making the house fully energy positive. This house acts like a miniature power plant, with 100% clean energy production.
Received Passive House Certification in February 2013 and LEED Platinum Certification in November 2013.