Imagine a zero-energy home that produces more energy from the sun than it uses. Now, envision building that home and turning it into a vacation retreat with a stunning view of snow-capped mountains — a place that won’t drain your checkbook, but will instead earn you thousands of dollars a month.
A few years ago, my wife, Alex, and I started dreaming about just these things. We had already achieved a piece of that dream — we’ve lived in a net-zero solar-powered house since 2011, when we built Seattle’s first zero-energy home for the price of a smaller townhouse in our neighborhood. It was such a positive experience that we wanted to try building a vacation retreat in Washington’s Methow Valley. Could our dream come true?
At the time we began to dream about our retreat, we had long been fans of the so-called “sharing economy.” We’d rented out a room in our house on Airbnb; set up a co-op for sailboats; and even rented out our biodiesel car to strangers. So, naturally, we began looking for partners for our house-building adventure.
Our friends Dave and Lisa also loved the hiking, mountain biking, and cross-country skiing available in the Methow Valley, and soon, we were making trips together, looking for the perfect plot of land. We knew we had found “the one” when we discovered a 3/4-acre parcel that was within walking distance of the little town of Winthrop, yet was perched atop a ridge with perfect views of the Cascade Range. We formed an LLC and purchased the land together.
Looking back, we were perhaps naive to think this second house would be as easy to construct and fund as our first. We quickly found that building costs were much higher than we’d expected. Not ready to give up on our dream, we decided to scale back the home’s size, act as our own general contractor, and tackle much of the finish work ourselves. Adding to the challenge, both of our families grew during construction. Alex and I had a newborn right after the foundation was poured, and Dave and Lisa had twins soon after. We were driving out to the site on weekends, a trip that could take up to six hours if there was snow, and camping in tents on the building site.
How the Home Works
Our 1,815-square-foot resort operates on 100 percent clean solar electricity; it doesn’t use propane, natural gas, or wood. It’s tied to the grid, but our electric meter goes both forward and backward, depending on whether we’re drawing electricity from the grid (as at night) or producing a surplus (as on sunny days).
To conserve energy, the walls and roof are made with structural insulated panels (SIPs), which are rigid foam sandwiched between layers of wood. The windows are triple-pane, and they’re positioned to let the sun warm the home in winter. The home is heated by two small Panasonic mini-split heat pumps, which also serve as air conditioners in summer. Our water heater has a small heat pump on top.
Our SIP walls were airtight to begin with. We took the time to do additional air sealing ourselves, caulking and taping every seam so cold drafts couldn’t come through. We installed a heat recovery ventilator (HRV) to bring fresh air into every room while helping to maintain the indoor air temperature.
While our energy-efficient cabin uses significantly less energy than a standard house, we still need to produce power to meet our zero-energy goal. We installed solar panels on our south-facing roof, and they can produce up to 5,400 watts on a sunny day.
Labor of Love
Making our home zero-energy added about $26,000 to the total cost. This includes the SIP framing, triple-pane windows, HRV ventilation system, energy-efficient appliances, and solar panels, after a $5,000 federal rebate. To control costs, we kept the design of the house as close to a cube as possible (which also saves energy), opted for finishes that were durable rather than decorative, and put in plenty of sweat equity.
Although our home cost more than it would’ve if it had been merely built to code, we saw immediate energy savings. Instead of paying the $220 per month in energy bills typical for our area, we pay only the $32 base service charge. For a limited time, Washington state will pay us about $1,200 per year for our solar generation.
We couldn’t get a traditional mortgage because of our co-ownership structure, but if we were to finance the $26,000 price difference of getting to net-zero over 30 years at 3.92 percent, it would add about $123 per month to the mortgage bill. Since we’re saving about $190 per month on our utility bills, we come out ahead by $67 per month. We don’t know whether the people who rent our house choose it because of its eco-friendly design, but it’s almost always rented when we’re not enjoying it ourselves. We’ve been renting it out for just over a year, and, after subtracting expenses, it’s providing each of our families with a monthly income of about $1,350.
So, our zero-energy goal added some complexity and cost. However, the costs were offset by lower utility bills, and the extra work was more than made up for by the satisfaction of knowing that we’re generating more clean, renewable energy than the home can use. We hope our zero-energy home project will inspire others to pursue similar dreams.
Eric Thomas co-organized the Northwest Green Home Tour and Seattle’s EcoBuilding Conference. He blogs about his zero-energy building experiences on the Artemisia Cabin website.