Oakland home uses zero net energy

March 14, 2010 12:00:00 AM PST
"This house was designed for net zero energy," said Andrew Silverman, "meaning the house produces as much as it uses. In order to make that happen, you need a smart system. So, if you want it cooler, sure the air conditioning system could fire up but that burns a lot of energy and we've got better ways of doing that without burning the energy. And, that's what this optimizes and controls."

Silverman, a VP with a company called ZETA Communities, points to a wall panel called zTherm™, a home controller to moderate indoor air temperature and quality in real-time. Within five seconds, it can draw cool air from the basement and open the skylights, more than 20 mechanical systems in all.

It was all shown recently during at a demonstration home in south Oakland developed by Silverman's company. Later, on the roof, he pointed out, "In addition to the solar panels, we actually have our own little weather station up here, being monitored in Colorado." The house meets LEED Platinum requirements with LEDs and compact fluorescents. Sure, you think to turn off the lights when you're leaving the house, but what about a switch to turn off everything else? There's one in the Oakland demo house for all the phantom power drawn by AC adapters, TVs and most appliances. All pipes are wrapped with heat exchanger coils.

"The shower drains at 95 degrees," Silverman explained. "The incoming cold water comes in around that at 65 degrees and by the time it gets to the top of the coil, it's 85 degrees. 30 percent preheating for free."

Warm air also is tapped to preheat water in the garage. But, a large part of savings is attributed by the company to rapid manufacturing, shipping, and installation, a prefab method ZETA plans for new apartment buildings, one of which is underway in Berkeley.

Green homes used to cost more, and it was a challenge to persuade homebuyers to shell out more up front for greater savings later. Even so, the house in Oakland sold for more than its asking price on the first day.