Page 6 - Zero Net Energy Case Study Homes-Volume 1

ZERO NET ENERGY CASE STUDY HOMES FOREWORD
Foreword
iv
Zero Net Energy Case Study Homes: Volume 1
What’s So Great About ZNE?
To some steeped in the culture of energy efficiency or engaged in efforts to roll back climate change, the value of zero net energy (ZNE) homes may be obvious. Yet it’s important that all the benefits of ZNE homes not escape notice. Indeed, to many individuals these benefits are likely to be of greatest value.
The most essential feature of a ZNE home is a high-quality thermal enclosure, with lower utility costs a benefit few are apt to dispute. Less well-recognized benefits – albeit equally im- portant – are increased comfort, and protection from excessive heat or cold in power outages. In some places, a solar energy system may be optional to achieving ZNE, as 100 percent renewable energy is offered by some California utilities and community choice aggregators
in an ever-increasing number of locales – at very low cost. A solar lease is another low- or no-cost option in many areas. In any of these scenarios, an enclosure built to ZNE standards carries valuable non-energy benefits.
Perhaps most importantly, as California reels from a series of devastating fires, resilience looms large as a universal goal. ZNE homes with solar arrays plus battery storage and con- trols will be able to serve as resilience centers in their communities, maintaining critical func- tions in power outages. The stringent durability and air quality standards to which ZNE homes are built bolster other aspects of resilience.
ZNE is the Future
This book, although describing just five projects, is an indicator of a nascent movement that is changing the face of American home-building, and doing so at a rapidly increasing clip.
Just a dozen years ago, in late 2006, Habitat for Humanity in Metro Denver produced utility data confirming, for the first time, a home that was operating at ZNE. That groundbreaking home, in Wheat Ridge, Colorado, was heralded in the February 2007 edition of Energy De- sign Update.
Today, the number of “ZNE-ish” housing units in the US and Canada tops 15,000. Recent growth has beeni exponential, with a one-year increase of 70 percent recorded in the most recent inventory. While ZNE homes still represent a tiny fraction of our housing stock, this burgeoning movement is making waves.
The first wave consisted principally of bespoke custom homes and one-off demonstrations.
In an interesting turnabout, the second wave has been dominated by affordable multifamily developments. The third wave, just starting to gather steam, is the adoption of ZNE by front- runners in the production home-building industry. These latter two groups evidence the viable business case for building ZNE homes at scale; this key finding – illustrated by two of the case studies in this volume – will be pivotal in transforming the housing industry.
State Influence on Housing
Another fact gleaned from the residential ZNE inventory is California’s preeminence as the state with the largest number of ZNE housing units. It is not coincidental that the State of Cali- fornia is also an energy policy leader – where there are advanced energy policies, innovation follows. Perhaps less obvious is the role of industry leaders in creating fertile ground for policy leadership. Were it not for successful models created by pioneers such as those highlighted herein, it would be much more challenging politically to enact ZNE-supportive policies.