Advanced Building Envelope, Materials Efficiency, Water Conservation, Rain Garden, Solar Power, Storm Water Infiltration
This Energy Star certified, 5-Star Built Green home produces as much electricity from the sun as it uses over the course of a year. By keeping the design simple and minimizing expensive finishes, the owners were able to keep the cost of building down to $124 per square foot ($114 after rebates and solar production incentives), which includes the 6kw solar panel system, taxes, and permits. Given that the average cost of construction in Seattle is $200/sf, this project demonstrates building green need not cost more than traditional construction. In addition to its energy-saving features, the house also incorporates reclaimed building materials and water conservation systems. Since moving in September 2011, the owners have been enjoying the home’s radiant floors, clean indoor air, and abundant sunlight.
Top 10 Questions about the Ballard Net-Zero-Energy House
1. What do you mean by net-zero energy?
Quite simply, this means that our solar panels produce slightly more electricity over the course of a year than we use for heating, cooking, lighting, and other household tasks.
2. Are you off the grid?
No. While we produce our own solar electricity, we’re still connected to the city’s electrical grid. We don’t have a bunch of batteries in the basement (actually, we don’t even have a basement). Why? Because storing electricity is inefficient, not to mention expensive. When you charge a battery bank, you don’t get as much electricity back as you put in. Some of it is lost as heat. That’s why most houses that have solar panels hooked up to a battery bank must rely on some other source for heat, like a wood stove.
3. So does all your power come from the sun?
People often ask us questions like this: “If you’re connected to the grid, you’re still using dirty power at night and on cloudy days, right?” The answer is–sort of, but not really.
It’s far more efficient and cost-effective to hook our solar panels up to the city’s electrical grid. That way we can put power into the grid during sunny days, when we’re producing more than we can use, and take it out at night and when it’s cloudy. It’s like we’ve set up our own little clean solar power plant, which means less natural gas needs to be extracted and burned and less electricity needs to be generated, avoiding all the associated negative environmental consequences. We like to compare it to a bank. When you have an excess of cash, you make a deposit. For all practical purposes, it’s still your money when you go to withdraw it from the ATM later, even if it was mixing with everyone else’s money on the bank’s balance sheet.
4. Does solar really work in Seattle?
Yes! Although we receive fewer hours of sunlight over the year, solar panels are more efficient in cooler places like the Pacific NW. Our long summer days more than offset our overcast winters. And, the fact is, our panels are still producing up to 1,000 watts on cloudy days. Even after installing 28 panels (enough to meet all our household electricity needs), there’s still room on our roof for enough additional panels to power an electric car over 5,000 miles per year.
5. What features allow you to achieve net-zero?
Our house was designed from the ground up to take advantage of the sun. Its passive solar layout means we have lots of windows facing south and few on the north side of the house. The house itself is built from structural insulated panels (SIPs), manufactured in Fife, WA, by Premier SIPs. An air-to-water heat pump, manufactured by Unico in St. Louis, lets us heat water for our radiant concrete floors and domestic hot water at over 200% efficiency. Triple-pane vinyl windows by Vinyltek were a cost-effective way to bring in lots of light and passive solar heat without losing much heat at night. We also made sure to select some of the most energy-efficient appliances on the market. By conserving energy as much as possible, we are able to offset all our electricity usage with a 6kw solar electric system, installed by Sunergy Systems in Ballard.
6. What other “green” features did you incorporate?
We incorporated reclaimed materials, including wide-plank fir floors from Salisbury Woodworking on Bainbridge Island, a cast-iron tub purchased from Craigslist, a cast-iron kitchen sink from Second Use, and other items. Our water-saving dual-flush toilets with a sink on top are definite conversation starters. We also have a rain barrel system made from old oak wine aging barrels (contributed by our builder, TC Legend Homes) which feeds all roof runoff into a large rain garden in the backyard. We have an active HEPA filtration system to provide fresh air and filter out allergens. And the house was engineered for low waste, which meant we never had to have a dumpster on site during or after construction.
7. Can I build a net-zero house of my own?
That would be great! We’ve been trying to show our house to as many people as possible in the hopes that we will inspire others to build to the net-zero standard. We started by finding stock plans on zero-energyplans.com, and our designer, Ted Clifton Sr., modified them slightly to suit our small city lot. We chose Ted’s son, Ted Clifton Jr., of TC Legend Homes, to build the house because of his experience with SIPs construction and because he’s a good guy. The building process was a lot of work for us, mainly because we took on some extra tasks, like pulling all the building permits and installing the wood floors ourselves. The actual building went quickly. In fact Ted and his crew of about three finished building a month ahead of schedule!
8. Can I convert an existing house?
Yes! Obviously, there aren’t too many empty lots left in Seattle, so retrofitting is going to play an important role if our city is serious about reducing its home energy use on a large scale. Luckily, there are lots of ways to making older homes much more energy efficient—and even achieve net-zero. You can start by adding insulation and sealing leaks and go all the way to wrapping the entire structure in exterior insulation and covering the roof in solar panels. Every little bit helps, and it’s often the simplest, least costly retrofits that have the biggest impact.
9. So how much does all this cost?
Out of necessity, we went into this project with the goal of keeping the cost of our new house about the same as the price of a townhouse in the neighborhood. The cost of the land was $180,000, and construction, solar panels, taxes, and permits added another $237,000. After a $9,000 federal rebate for the solar panels, and an approximately $9,000 WA solar production credit (paid out over 9 years), the grand total came to about $399,000. We were pleased because the cost to build was only $124 per square foot ($114 if you count the rebates and incentives), whereas the average in Seattle is $200 per square foot. Plus, we won’t be paying for energy, which comes to about $150 per month, or $1,800 per year, for the average Seattle household.
10. Should I do this?
Absolutely. Go for it! Building this house has been really rewarding for us, and we’d love to help others pursue the net-zero-energy goal. So feel free to get in touch with us if you’re thinking about it and have questions. You can also check out our blog at zerohouse.wordpress.com, where we’ve documented the building process.
Specs: 1,915 square feet, single-family, 2 stories, 3 bedrooms + work loft, 2 bathrooms, concrete slab foundation, radiant heat floors, Hardie plank siding.
Green features: Structural Insulated Panel construction, air-to-water heat pump, 6kw solar electric (photovoltaic) system, triple-pane windows, passive solar design, rain garden, stained concrete floors, reclaimed fir floors, recycled fixtures, zero-VOC paint, low-waste engineering, low-energy LED and CFL lighting, capacity for additional solar panels to power an electric car 5,000 miles per year.
More Information and Photos: zerohouse.wordpress.com