Water Conservation, Energy Efficiency, Indoor Air Quality, Materials Efficiency, Design Innovation, Advanced Building Envelope, Electric Vehicle, Solar Power
As a physics and environmental science teacher, I’ve known for a while that we need to radically change the way we use energy. Six years ago, my wife and I decided to move our family from Seattle to create our Duvall homestead. My goal was to design and build an environmentally responsible net-zero energy home on a tight budget. I wanted this home to be an example for how all buildings need to perform, if we are to pass on a healthy planet to our children. The first step was to reduce our energy demand as much as possible, so we built to Passive House standards.
Renewable Materials: We chose materials that are renewable and built a high-quality home that will last for hundreds of years. We used cedar siding, corrugated metal siding, standing seam metal roof and dense-packed cellulose insulation instead of petroleum based foam.
Assemblies: The double-stud wall was framed with advanced framing techniques, provides an R-value of 48 and eliminates all thermal bridging. OSB served as the air barrier with all seams sealed. The parallel-chord trusses allow usable space in the loft and a roof R-value of 80.
Passive House standards: The heating load for the house is 1800 W, meaning that a hair dryer can heat the house on the coldest day of the year. We achieved an air tightness of well below 0.40 ACH 50. Windows are triple-pane and Passive House certified. A heat recovery ventilator (HRV) provides a constant supply of fresh air, while recovering the heat from the stale air that is vented outside.
Energy Efficient appliances: The house maintains a constant temperature, so the ductless air source heat pump remains off most of the day. The heat pump water heater and heat pump dryer are the most energy efficient appliances available.
Saving the planet and saving money: The house uses about 10% of the energy for heating and 25% of the total energy compared to the average house in the U.S. All of the additional material and labor beyond what is required by code to bring the house up to Passive House standards increased the cost of the house by 5%. We are saving more money every year because of reduced energy bills than the additional cost of that 5% adds to our mortgage payment. That means it is cheaper from day one to build a more comfortable, more energy efficient home. We were aiming for a net-zero energy home, but we blew past that goal. The 11 kW PV system on the roof produces 180% of the home’s energy use. This provides enough extra electricity for two electric cars to travel 20,000 miles each year. The $45k spent building beyond code and installing solar panels will be recouped in only 6 years. This is equivalent to a guaranteed 6% ROI for the rest of your life.
Homestead: Part of our goal of living more sustainably includes producing as much of our own food as we can. My wife tends a large garden with a great variety of fruits and vegetables. Our children take care of the goats, free-range chickens and the rabbit. The beautiful garden and animals will be open to tour. Bring your entire family to see the five baby goats!
Tour: As the home owner, designer, general contractor, builder, electrician, plumber and laborer, I have a unique perspective on the entire home-building process. There are countless ways to build to Passive House standards and achieve a net-positive home and I would love to discuss their advantages and disadvantages with you. As an educator, I will have signage around my house to explain each of the features, with all of the graphs, data and money savings. I look forward to meeting you when you tour our home!
Learn more on the project blog here: https://sustainabilityissues.wordpress.com/about/