What is a Zero Net Energy Building?

A zero net energy building (ZNEB) is one that is optimally efficient, and over the course of a year, generates energy onsite, using clean renewable resources, in a quantity equal to or greater than the total amount of energy consumed onsite.

A zero net energy building (ZNEB) is one that is optimally efficient, and over the course of a year, generates energy onsite, using clean renewable resources, in a quantity equal to or greater than the total amount of energy consumed onsite.

Getting to Zero in Massachusetts

To create ultra-efficient residential and commercial buildings, designers and builders utilize integrated design and building techniques. They also determine which energy efficiency strategies and technologies, and what type of renewable on-site generation, will contribute to superior energy performance to meet the needs of the buildings. These elements will create a comfortable, healthy home or workplace; decrease energy costs; and reduce greenhouse gas emissions -- all characteristics that make ZNEB buildings desirable and rewarding.

These case studies, featuring zero and near zero net energy buildings, newly built or retrofitted, are designed to inform and inspire you to consider what's possible. Indeed, innovative designers, builders, and homeowners are transforming the way we build in Massachusetts, demonstrating much needed solutions to reduce energy waste.

Case Studies-Residential

Existing Homes: Deep Energy Retrofits

The Arlington House Project

Arlington, Mass.

Design: Building Sciences Corporation

Builder: Synergy Companies Construction

Other Collaborators: DOER; NSTAR Electric; Anderson Insulation

Livermore Residence

Gloucester, Mass.

Design: Livermore Energy Associates; Energysmiths

Builder: John Livermore


Westborough, Mass.

Design: Caroline Fisher; assisted by Yestermorrow Design/Build School

Builder: Jay Hartnett Construction

For many homeowners, deep energy retrofits in the current market are cost-prohibitive. However, increased incentives and financing mechanisms, rising fuel costs, and a growing demand for "green" housing, are expected to facilitate the affordability and widespread implementation of deep energy retrofits. Building experts estimate that as the market grows, material and labor costs will decrease from 25 to 50 percent. Furthermore, with existing government and utility incentives (tax credits and rebates), incremental approaches to super-insulation are accessible to many homeowners as these projects are most cost-effective when a building undergoes a major renovation such as a new roof, new siding, or window replacement.

New Home Construction

Montague Urban Homestead

Turner Falls, Mass.


Design: Doug Stephens, Tina Clarke, and Bick Corsa

Builder: Bick Corsa

Other Collaborators: Conservation Services Group; Limbach Engineering and Design Services; Center for Ecological Technology; Western Mass Electric


Townsend Case FINAL.pdf 

Townsend, Mass.


Builder: Transformations, Inc.

Other Collaborators: Team of design and energy expert


Wisdom Way Solar Village 


Greenfield, Mass.


Design: Steven Winter Associates, Inc.; Austin Design

Builder: Rural Development Inc.

Other Collaborators: Joan S. Rockwell & Associates (landscaping)

For more information about the various energy efficiency specifications and other characteristics of zero net energy construction, refer to the U.S. Department of Energy's website: zero energy home design. See the Residential Energy Services Network to learn about the HERS Index (Home Energy Rating System), a standard rating for residential energy use. 

First State-Owned Zero Net Energy Building: North Shore Community College - Health and Student S

Leading the way toward a cleaner energy future, the Commonwealth opened the first state-owned zero net energy building, one of the largest of its kind, in the fall of 2011. Over the course of a year, the building will produce as much energy onsite as it consumes. The 58,000-square-feet, three-floor building at the North Shore Community College (NSCC) in Danvers will provide new classrooms, labs, and offices for the campus.


The NSCC building's integrated design consists of a south-facing horizontal design, an enhanced building envelope including R-24 to R-30 walls and R-5 windows; chilled beams to provide air conditioning; LED lighting and occupancy sensors; solar sun shades and light shelves; and natural ventilation. The building will utilize onsite clean energy technologies, including a 50-well geothermal closed-loop system and 340 kW of solar panels on the roof and in the parking lot. Other "green" design features include a green roof, low-flow fixtures, permeable pavement, and native landscaping. The design, efficiencies, and technologies result in an energy demand of only 27 kBtu per square foot per year for the building -- well below a comparable "average" building in this climate, which would require approximately 60 to 80 kBtu/year of energy per square foot.

With utility costs projected at zero, the new super-efficient Health and Student Services Building will benefit the Commonwealth in several ways:

  • Reduce annual grid electricity consumption by approximately 409,000 kWh annually, which will save an estimated $142,000 per year
  • Save roughly $3.5 million in avoided electricity bills over the next 20 years (the approximate life of the PV system), assuming a 3% annual increase in energy prices and other efficiency factors
  • Prevent approximately 4,000 metric tons of carbon emissions over the 20-year period, equivalent to eliminating 780 cars from Massachusetts roads or the electricity use of 500 homes


Construction Management: Mass. Division of Capital Asset Management
Architects: Dimella Shaffer
Copley Wolff Design Group (Landscape)
Engineers: RDK engineers (Mechanical, Electrical, Plumbing)
GZA & Alderson Engineering (Geothermal Design)
Buro Happold (Environmental Consultants & Energy Modeling)
Nitsch Engineering (Civil)
Consultants: Putnam Associates (Specifications)
RW Sullivan (Code)
Solar Design Associates (Renewable Energy)
Contractor: Walsh Brothers, Inc.

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