Reviewing "Toward a Zero Energy Home"

A few months ago in late spring I read Toward a Zero Energy Home - A Complete Guide to Energy Self-Sufficiency at Home by David Johnston and Scott Gibson.  Or shall I say devoured it hungrily.  I read it on a cross-country flight in one sitting.

2010, The Taunton Press

The book begins by making a great case for the zero energy house by framing the view through the energy price bubble of 2008 and the need to shift behaviors moving forward.  Ironically in the spring of 2011 we were experiencing another price bubble seeded by political instability driven by the unprecedented democratic spring of Egypt, Syria, Libya and elsewhere.  Once again prices spiked ever higher over the course of late winter and spring.  Fairly quickly it seemed, world-wide strategic oil reserves were tapped to temper the price spikes and people's fears abated but high prices linger.  Today, the US Energy Information Agency says gas prices are up $0.91 from a year ago.

If you consult the EIA's interactive tables and build predictions out to 2035 you'll find an average yearly growth rate of 3.5% for residential fuel oil costs.  So in about ten years prices may rise 35% over today's already high rates.  With the unpredictability of the global geo-political climate and growing effects of global warming, growing population pressures and scarcity in fossil fuels, radically reducing energy consumption is urgent.  More predictable energy costs and growth in resource conservation is critical to creating a more sustainable future "softening the hard landing to come" as said by Bill McKibben in his recent book, Eaarth.

While residential delivered energy consumption has been going down historically in a gentle slope since 1990 the EIA forecasts four different scenarios showing reductions.  The reference light blue line models this continuing fall while the magenta (high tech usage) and green (best available technology) go even lower.

As energy costs continue to escalate residential users will naturally seek to conserve.  The space between the purple and green line is where Toward A Zero Energy Home plays an important role today in driving best practices  in zero energy home design into the marketplace towards consumer acceptance.

The book is organized into five chapters; The Building Envelope, Passive Solar Design, Renewable Energy, Heating-Cooling-Ventilation, Living a Zero Energy Life.  In each chapter they provide helpful overviews going over the basic components, design strategies and approaches with insightful case studies from around the country relating to the chapter focus.  The case studies provide wisdom from the field about how projects develop and mature between owners, architects, builders and energy consultants.

I recommend this book.  It tackles a very complex subject and breaks it down to basic elements where the complexity supports the big picture of why certain strategies are valuable varying by budget, climate, owner likes and dislikes, project delivery methods scalable for a variety of situations.  Whether seeking to do a custom design and build home, or hybridized process with some level of factory panelization and custom building, or finally, full out factory built and controlled modular home with quick onsite assembly the book has insights valuable for all.

The book also shows how fast moving high performance building science and knowledge truly is.  After this book came out, Alex Wilson's published a groundbreaking article in Environmental Building News on the Global Warming Potential of Foam Insulation.  Their research led to a wholesale re-evaluation of the viability of using closed expanding cell foam and related insulation materials in building envelopes because of the long-term costs of using fossil fuel as blowing agents.  Many of the case studies homes in the Toward a Zero Energy Home used closed cell insulation in some aspects of the building envelope.  The new research indicated the need to look more closely at using open cell insulation or other more benign alternatives such as cellulose insulation instead going forward.  Hindsight is 20/20 though and admittedly best practices will always be evolving to ever-higher standards.



The authors also covered the Passive House movement, a subset within the Zero Energy home design area, focusing on super high insulation and air-sealing levels dramatically reducing the need for heating and cooling systems or eliminating them entirely.  Originating in Germany about 15 years ago as Passiv haus this movement has gained serious traction in the U.S. with use of the Passive House protocol growing around the country.  Passive House consultants use the (PHPP) Passive House Planning Protocol software to model building envelope choices, building siting, heating and cooling systems to derive solutions which ultimately can be certified as Passive Houses and used to verify actual energy use later.

The authors did not focus much on life cycle thinking or cradle to cradle systems and did not cover the USGBC LEED for Home process to any great detail or the drive improving national and statewide building energy performance standards.  Perhaps this is for a more policy oriented book.  Adding a chapter on how to approach verifying performance, commissioning buildings after completion, and what if any third party verification systems could be used and the value they add would have been helpful.

Towards a Zero Energy Home does however do a great job on what it set out to do, develop a set of usable and approachable guidelines to move to a more energy conserving, efficient and independent future.
For those just starting out in this process as a homeowner or affordable housing non-profit with little experience in this area, or seasoned professionals you will find this book a tremendous resource.