SOLAR TODAY Blog

Oct 9: Two days ago I commented on the vast difference, both in design philosophy and cost, between two of the houses in this year's Solar Decathlon. The Team Germany entry was designed to 'push the envelope', to maximize solar power output with minimal regard for market pricing of the house, and seems to have succeeded in that aim. Other entries, notably that of Rice University,* have targeted a price range that would make a solar house a realistic option for municipal housing projects or middle-income buyers.

The Rice philosophy reaches beyond the parameters of the competition. It has been the team's intention from the outset to design a home that they could -- and would -- give back to the community. Within a few weeks of Rice's house leaving Washington at the end of the competition, it will be handed over to Houston's Project Row Houses for use as a family home in the city's Third Ward. It will eventually be joined by five similar houses, some of which will be two-story. It was the agreement with this neighborhood-based organization, in fact, that led to the building being christened ZEROW HOUSE; (note: student humor).

This does not mean, however, that the Rice team is building a slum. "The house we built already has a life beyond the Solar Decathlon, so it's important that we get this right," said David Dewane, team architecture lead.

The Rice house has a total footprint of some 800 square feet, with internal space of 520 square feet. Like most of its competition here it aims for net zero use of energy, but with a solar array of only 4.2kW to keep construction costs under control. With the house's ultimate use in mind, the team designed the PV panel racking to be reversible, to accommodate different siting plans in Houston. Compared with some of the more sophisticated set-ups in the solar village the building optimization system is somewhat simple, but it does feature a monitored micro-inverter on each of the twenty-four panels, allowing residents to precisely identify any panels performing poorly.

At first glance, Zerow House appears short on window area for passive daylighting, but the architectural design includes what the team terms a 'light core' -- a glass-encased volume inserted into the building envelope that acts as both an exterior extension of the living space and the source of daylighting. As for active lighting, the house makes extensive use of LEDs, including state-of-the-art LED strips attached to the walls and ceilings. The result is that the total energy use for lighting is about 250W, less than that used by three standard 100-W light bulbs.

What appears to be old-fashioned corrugated iron on the building walls is an easily maintained alloy known as Galvalume, 35% of which is recycled material. Rebecca Sibley, a graduate architectural student, told me that the walls were six inches deep, and filled with Icenyne spray insulation -- a sustainably developed material based on Canola seeds.

So how will the down-to-earth Zerow House fare against some of the more gee-whiz (and gee-that's-expensive) designs in the solar village? It will be a week before we know for sure -- currently the online leader board is tantalizingly empty except for those contests scored every 15 minutes for the duration of the event -- but the Rice students' week will be, as we euphemistically term it these days, "challenging". Perhaps the final judgment on their efforts will be in years to come, if more organizations like Project Row Houses embrace their low-cost, net-zero-energy approach. As Danny Samuels, faculty advisor to the team put it: "We always opted for making it practical. We saw it truly as a market demonstration of what is feasible and possible, to show that an affordable house can be energy-efficient and available to basically everybody."

And isn't that where we should all be headed?

*Rice isn't the only team thinking this way; the home built by Team Boston, although at more than double the cost of the Zerow House, has already been sold to a developer on Cape Cod for a post-homeless community sponsored by the Housing Assistance Corporation there. More about that on a future post.