News Brief

The New Net Zero

Architect Bill Maclay’s new tome packs a lifetime of experience on low-energy buildings into a tremendous resource for practitioners.

Photo: John Earle. Inset: Chelsea Green Publishing.
This isn’t a book for bicycle commuters to lug around! At more than 550 pages, the oversized volume weighs in at an impressive five pounds. But it’s worth every calorie you might expend carrying it. In fact, if I could recommend only one book today for designers and builders of low-energy, green homes and small commercial buildings, this would be it.

The New Net Zero is organized into five parts:

  • What is Net Zero?
  • Net Zero Design
  • Core Construction Practices
  • Expanding the Net Zero Horizon
  • The Net Zero Journey

But preceding this, in the preface, I was fascinated to learn of Maclay’s background, going back to inspiration from solar pioneer Steve Baer in 1970 and then his involvement, starting as a graduate architecture student in 1971, designing Dimetrodon in Vermont, a small-scale renewably powered community of compact homes—much like cohousing, which would emerge decades later—where Bill and his wife lived for 20 years, raising a family.

Putting net-zero in its place

In Part I, three chapters lay out the context of the book. Chapter 1, “Energy and Transition,” provides the requisite “whys” of net-zero-energy buildings: resource issues, the inevitable transition away from fossil fuels, renewable energy, smart grids, and philosophical perspectives on energy, beauty, and human settlement.

In Chapter 2, “Defining the New Net Zero,” Maclay lays out, clearly and succinctly, what is meant by net-zero energy, how definitions of net-zero differ, understanding energy use intensity (EUI), various energy conservation standards and codes, net-zero-energy vs. carbon-neutral buildings, and what it means to extend net zero beyond the building scale. Chapter 3, “The Roots of Net Zero Design,” examines some of the architectural forces and trends that have moved us toward net zero, touching on the LEED Rating System, but devoting much more attention to the Living Building Challenge, which has net-zero-energy performance as a keystone principle.

This chapter includes the first of eleven in-depth case studies of projects designed by Maclay Architects, each of which is packed with design details, performance information, and photos. The first of these case studies, at eight pages, is the Bosarge Family Education Center at the Coastal Maine Botanical Gardens.

Systems and processes to make it work

For many readers, Part II, “Net Zero Design,” will be the motivation for buying The New Net Zero. Four chapters, comprising nearly 200 pages, provide the fundamental design principles needed to achieve net-zero-energy performance. Chapter 4, “Integrated Design Fundamentals,” provides very clear guidance on passive solar design, starting with a primer on how the sun moves across the sky and how that should inform design. Heating degree days, cooling degree days, building geometry, massing, daylighting principles (in both small and large buildings), natural and mechanical ventilation, and strategies for capturing renewable energy sources are all covered here, along with a 12-page case study of the George Aiken Center at the University of Vermont.

In Chapter 5, “Integrated Design Process,” Maclay describes how to put the right team together to achieve top energy performance and how to work effectively with that team. The case study of the Putney School Field House, the nation’s first net-zero-energy secondary school building (just up the road from BuildingGreen in Putney, Vermont), helps to illustrate how an integrated design process works.

Given how critically important the building envelope is in achieving net-zero-energy performance, it’s not surprising that Chapter 6, “Net Zero Building Enclosures,” spans almost 50 pages. Covered here are the basics of thermodynamics, insulation choices, calculating building assembly R-values, air barriers, moisture control (the latter including drainage planes, flashing details, vapor permeability, and related building-science issues), and windows—plus a case study on the Middlebury South Village Professional Office Building.

Chapter 7, “The Essential Elements of Net Zero Buildings,” gets into the nuts and bolts of calculating energy loads, EUI metrics, different heating and cooling systems, other energy loads in buildings, ventilation options, and renewable-energy options. The chapter includes a well-illustrated case study of the NRG Systems office buildings in Hinesburg, Vermont.

Construction details galore

Part III, “Core Construction Practices,” is comprised of seven chapters filled with construction details and lessons learned from 40 years of low-energy building design. Large, two-dimensional illustrations and photographs convey these details very clearly for a wide range of construction systems—some mostly relevant to residential building, others more applicable to commercial building.

For many designers and builders, the in-depth, well-tested details showing such features as continuous air barriers, moisture-control options, below-grade construction, and control of thermal bridging will easily justify the (not insignificant) price of this book.

Part IV, “Expanding the Net Zero Horizon,” expands the discussion back out to the macro scale, with chapters on “The Case for Renovation,” “The Case for Net Zero Homes,” and “Why the Cost Is Right.” The first two of these chapters (15 and 16) are packed with detailed case studies of Maclay’s projects as well as profiles of other projects around the country.

Chapter 17, “Why the Cost is Right,” gets into complicated economics, including discussion of fuel cost escalation, discount rates, operating costs, payback, return on investment, net present value, internal rate of return, etc. This information, while complex, is absolutely critical in selling clients on net-zero-energy targets, and it can be critical in financing projects—so take the time to plow through it. The chapter also addresses such issues as resilience, market conditions relative to leased net-zero buildings, and societal benefits of net-zero buildings (through reduced pollution emissions and minimizing the heat island effect, for example).

Part V, “The Net Zero Journey,” lays out a twelve-step program for achieving net-zero buildings (Chapter 18)—see table below—and provides a concluding chapter, “Net Zero Communities and Beyond.”

1.   Build and empower your team

2.   Engage with a collaborative process

3.   Explore, understand, and discover

4.   Embrace a bold vision

5.   Commit to metrics

6.   Design living buildings and places

7.   Minimize energy loads

8.   Optimize systems for comfort and efficiency

9.   Power with renewables

10. Detail and build

11. Learn and operate

12. Celebrate

The New Net Zero, for those practitioners who take the time to read and digest it, will change the way they work. It is a veritable encyclopedia of highly detailed yet clearly presented information, some of which is available nowhere else.

For more information:

The New Net Zeroby William Maclay and Maclay Architects

Chelsea Green Publishing CompanyWhite River Junction, Vermont

June, 2014; $90, hardcover

Published September 2, 2014

Wilson, A. (2014, September 2). The New Net Zero. Retrieved from

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