The Tour That Sparked My Interest in Net-Zero Building

What: The 2014 Northwest Green Home Tour

When: Saturday, April 26, 11am – 5pm

Where: 47 homes and commercial sites throughout the greater Seattle region

Info and map: www.nwgreenhometour.org

Tickets: Free event, no tickets required. Official tour program printed in Seattle Natural Awakenings magazine

Since last January, I’ve been hard at work organizing the 2014 NW Green Home Tour, but my history with the event starts much earlier than that.

Back in 2011, shortly after Alex and I moved to Seattle, we saw a sign on the street for the tour while we were taking a walk. We were looking for building ideas at the time and wandered into a beautiful 100+ year-old home that the owners had substantially renovated and insulated to the point where their solar panels almost produced all their power. This was still a somewhat novel concept for us at the time, and it  helped inspire us to build our own net-zero-energy house a few blocks away.

In fact, the next year our house was complete, and we had made the last-minute decision to include a full PV array in our construction loan and target net-zero ourselves. I got involved as a volunteer with the tour, and it eventually occurred to me to try to give something back to the Seattle community by putting our own house on the tour. Another nearby resident, Becky Chan, toured our house that year and eventually went on to hire our builder, Ted Clifton, to substantially renovate her own fixer-upper house into a modern net-zero-energy home, which, you guessed it, she put on the tour to inspire yet more potential home builders and renovators to take on the net-zero goal.

Sure enough, Ted Clifton is back this year with another net-zero house, this one designed to power not only itself but the owners’ electric car. Another impressively renovated home on this year’s tour does the same.

Last year, the Northwest EcoBuilding Guild and Built Green hired me and a colleague at Sustainable Ballard, Jenny Heins, to organize the tour. It’s been a ton of work, much more than I had anticipated, but an honor and a pleasure to organize such a fantastic event.

If you live in the Seattle area, I hope you’ll consider touring some homes on Saturday. Who knows, maybe you’ll be the next to continue the virtuous cycle of taking inspiration from what you see and building your own net-zero house.

We’re also still looking for about five volunteers, and we’d appreciate your help. More info.

 

NW Green Home Tour

 

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Passive House Versus Net-Zero-Energy House: What’s the Difference?

Passive House

Our builder, Ted Clifton, just finished his latest house in Leavenworth, WA. We were disappointed that we had to miss the housewarming party, but from the photos, it looks really cool.

Unlike our net-zero-energy house, this new one follows the stringent Passive House standard, developed in Europe.

The hallmarks of a Passive House are super-high levels of insulation, a design that takes advantage of passive solar gain, and, as a result, has little need for heating beyond that provided by the sun, warm bodies, and appliances. Passive Houses also come with a list of requirements, like a heat recovery ventilator, a somewhat costly piece of equipment that recoups some of the energy that would normally be lost from circulating fresh air through the house.

Are Passive Houses better than net-zero houses? It depends who you ask.

We opted for the net-zero approach because producing as much energy as we used over the course of a year was our first priority. Passive Houses can be net-zero, too, but it’s not required by the standard, and it adds to the building costs.

Upstairs Passive HouseThe focus of Passive House design is to reduce the amount of energy required to heat and cool the house (by up to 90%), whereas the focus of a net-zero house is to offset 100% of the power required to heat, cool, light, and run the home. In any given moment, a net-zero house like ours might be using slightly more power than a similarly sized Passive House, but it would make it all back from its solar panels over the course of a year.

Passive Houses tend to cost more to build since they have even more insulation than a typical net-zero house. Critics of the PH standard point to diminishing returns. To chase after that last little bit of air tightness and insulation to bring a house up to the Passive House standard can be expensive, and, in many cases, the potential energy savings could be easily and much more cheaply attained by adding a few solar panels.

On the other hand, Passive Houses are elegant in the simplicity of their mechanical systems. Some of them require so little auxiliary heat that they can be warmed solely by a cheap little wall-mounted electrical heater, eliminating the need for costly heating systems. Proponents of Passive Houses point to the fact that mechanical systems eventually wear out and solar panels stop producing as much power over time, while a well-built, well-maintained house can last hundreds of years.

Boulder TableDuring our first winter in our house, we spent a lot of time tweaking the radiant heat system, and our heat pump required a replacement electrical board (under warranty, but still a hassle). The reality is, however, that many Passive Houses, especially larger ones in colder climates, also make use of heat pumps. And, if you’re interested in achieving net-zero-energy, you’ll need to install solar panels and an inverter on your Passive House.

Looking back on it, we wouldn’t have turned down the extra insulation the Passive House standard calls for, but not if it had required us to have smaller windows or forgo our net-zero-energy goal. By not strictly limiting ourselves to the rigid standard, we were able to achieve net-zero much cheaper.

Either way, both types of house save lots of energy, and I’m happy to see them being built. Plus, Ted’s newest project is just plain cool. Check out the sliced-off boulder table in the middle of the room!