Zero Net Energy zHome is "A Model For Mainstream Housing In The Future"

zhome net zero energy housing seattle photo

images credit zHome

On September 29, 2008, the Down Jones Industrial Average fell 777 points, the economic crisis and Great Recession started, and they broke ground on the zHome project in Issaquah, Washington. Now, three years later, the project is complete and the units are for sale.

The 10 unit townhouse project is spearheaded by the City of Issaquah and designed by David Vandervort Architects. (see other partners and contributors here) When you get past the obvious eco-bling of the solar panels, there is a lot of substance to it.

zhome net zero energy housing seattle photo

One of the few images not dominated by solar panels, the courtyard

The project is net-zero energy, defined by Project Manager Brad Liljequist in Dwell:

To achieve zero net energy, zHome is tied to the electric grid. During the summer, when the homes use less energy than is produced by rooftop solar panels, zHome is a net energy generator. In the cold winter, when solar production is lower and energy demand is higher, zHome will draw energy from the grid. Based on our commercial grade energy model, the electricity generation and use will average out to zero over the course of the year.

zhome net zero energy housing seattle photo

But the real significance of the zHome is that it is a total package, that the designers and builders realize that there is more to building green than just sticking solar panels on top. Along with energy use and carbon emissions, they were concerned about

Indoor Air Quality
EPA studies found levels of about a dozen common organic pollutants to be two-to-five times higher inside homes than outside. Dust, volatile organic compounds, urea formaldehyde, mold and other toxins all create potential health impacts for residents, including asthma.

In many locations, water is pumped from an aquifer that is connected to salmon-carrying streams above. If too much water is pumped out of the aquifer, stream levels may drop, harming salmon and other wildlife. Many reservoirs provide water for both human use and river flow. If too much is used by humans, there may not be enough to sustain salmon runs. Water also requires significant energy to pump, treat, heat and move around--another impact on carbon emissions. And finally, as our region's population continues to grow, minimizing water use, even in non-drought years, is critical to ensure there's enough to go around (for us humans) now and in the future.

Whether it's clearcuts for lumber, quarries for sand and gravel, oil drilling for asphalt and roofing, or the huge amounts of CO2 generated in concrete manufacture, construction of buildings have a direct impact on the environment.

Construction waste within the United States amounts to 2.8 pounds per person per day! Reducing construction by using fewer raw materials and recycled-content products whenever possible means less waste going to our landfills.


They approached the problem with all of the un-blingy things that make a real difference in the quality of life and the energy consumed, namely lots of insulation (R-38 walls and R-60 ceilings), high quality windows and very tight sealing, a heat recovery ventilator to deliver fresh air, a ground source heat pump for heating and cooling, 78% built from FSC certified lumber. The solar panels are really just the cherry on top of a very nice sundae.

zhome net zero energy housing seattle photo

It is also multifamily and relatively dense, townhouses around a courtyard. That's important; we have seen enough single family suburban houses. They do some very interesting design moves, too; the Units on the right do not have parking in the units themselves;

zhome net zero energy housing seattle photo

The ground floors in Unit type C appears to share space for parking with the other units. This is almost un-American.

zhome net zero energy housing seattle photo

The units are selling for between $ 400,000 and $ 600,000, which Jeff McIntire-Strasburg says is "mid-price range for the market" and " pretty reasonable for the Seattle area." I don't know what houses go for in that area in this market, but I do remember, as an architect, trying to convince a developer client that a powder room took up too much space. He said "you can't sell a house without a toilet on the ground floor, people come home and have to pee." In these houses you have to run all the way up to the third floor before you find a bathroom.


But they look like very comfortable, efficient two bedrooms plus neat loft.

zHome claims to be the first net-zero community in America. It broke ground on an inauspicious day in history, and comes to market at a time when America may be tipping back into serious recession. It should be, as Brad Liljequist calls it "a model for mainstream housing in the future." I hope he's right.

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