Links to Deep Energy Retrofit and Reduction Case Studies

LA County, California Net Zero Energy Retrofit

 The Green Idea House ( is one family’s project to affordably retrofit their house into a net zero energy, zero carbon case study. The building has surpassed all our net zero energy, zero carbon goals, is a joy to be in and won the 2012 Green Leadership Award for Los Angeles County, 2012 Environmental Leadership SEED Award is a case study for Energy Upgrade California and Build it green’s Green Point Rating. It is also the cornerstone case study for Southern California Edison’s Net Zero Energy Initiative that makes possible the CPUC’s guideline that all new residential buildings be net zero energy by 2020.

The Green Idea House also kept over 97% of construction waste out of the landfill and was also extremely responsive to issues of materials use, water and toxicity. Grid.


Quincy, Massachusetts Deep Energy Retrofit

A 1903 bungalow was transformed to a 4 story, state-of-the-art 21st century home as part of a Pilot Deep Energy Retrofit project, sponsored by National Grid.
Link to more information here


Boston, Massachusetts Multifamily Deep Energy Retrofit

Castle Square Apartments is a 500-unit 1960s-era, affordable property.  A portion of the property, the 192-unit midrise, is expected to slash energy usage by 72 percent, in part due to a new exterior super-insulated enclosure.
Link to


Concord, MA Retrofit House Case Study

This is a case study about a deep energy retrofit of a Sears Roebuck house by Betsy Pettit. It is found at the Building Science Corp website.
Link to Concord Retrofit House Case Study


Sonoma, CA Deep Energy Retrofit Case Study

This retrofit is shooting for the Passive House certification. It is found at the Green Building Advisor website.
Link to Sonoma Retrofit House Case Study


Aspen, CO Green Builder VISION House Case Study

This retrofit is part of the Green Builder VISION House Program that showcases retrofit homes utilizing green design, building techniques, and products & systems. It is found at the Green Builder Magazine website.
Link to VISION House Aspen Case Study


Cador Price-Jones Case Study

This home in Somerville, MA is a duplex (upstairs/downstairs). The deep energy retrofit involved strictly energy upgrades (interior of walls in basement, exterior of walls above-grade, and ceiling plane of attic).
Link to Cador Price-Jones Case Study

More Links:

Greenification of An Old House Blog
Keith Akers Superinsulation

Massachusetts Super Insulation Project
Community Land Trust Association of West Marin
Article about Pat Murphy's Retrofit
Ray Darby's Retrofit
Now House Windsor 5
San Francisco Chronicle on Steve Greenberg
Home Energy Magazine on First U.S. Passive House Retrofit
Brattleboro, VT Deep Energy Makeover 
Gordon Scale Deep Energy Retrofit

Thanks to Saturn Resources Management for supporting the development of the deep energy reduction Case Studies.



The House on Hummingbird Hill, Salinas, California


(Updated Dec 04, 2013) Larry and Suzanne Weingaten’s home in Salinas is the 13th to officially meet the Thousand Home Challenge. This 6-year old off-grid home features:  a high performance building enclosure; very low electrical and water use (kW and kWh) through system design; careful placement of fixed and operational windows for optimum climate control and thermal comfort; and space and water heating systems designed to optimize solar inputs, and minimize parasitic energy use. Meeting the Challenge required modest changes and an equally modest investment that included replacing the propane-fired refrigerator with a 24-volt DC refrigerator and a separate  24-volt freezer and reducing wood used for space heating. Their 1,800 square foot home used 3,207 kWh in site energy during the monitoring period, 40% less than their OPTION B allowance. 

Click here to download this PDF


John Livermore Case Study

 Updated 8-09-13 – Completed in 2008 on a budget of $60,000, this deep energy retrofit of a 1970s raised ranch in Gloucester, Massachusetts achieved zero net energy in 2010. This project's energy use has met its Thousand Home Challenge threshold allowance for the past four years. It will officially meet the Thousand Home Challenge when the application is completed For more information:

Click here to download this PDF


Maine Antique Rehab -- A Staged Deep Retrofit Project

(Updated 03-03-2014)  Bill Turner tells the story of his home in Maine where superinsulation work began in 1981. He describes what he did wrong, and what he has done recently in an effort to bring the home from its 2011-12 baseline of ~62,309 kWh (equivalent site energy) to its Thousand Home Challenge OPTION B threshold of 11,814 kWh/year.  Concern for indoor air quality and durability have been considerations since the beginning.  Check out the impressive progress to date with this Thousand Home Challenge Candidate. Results show the impact of strategic densepack of a previously insulated home, combined with renewables, reduction of DHW and plug loads, and the use of a ductless heat pump to further offset wood use.

Click to download this pdf


Monahan Zero Energy Home Case Study

Updated 05/13/13 - Located in Albuquerque, NM this 1950 vintage ranch home is the 19th project to officially meet the Thousand Home Challenge and the first one from the southwest. When purchased in 2009 this 1,600 home featured no insulation, no heat, no water, and no southern exposure. Find out why the owner claims his biggest mistake was the replacement of hazardous floor heaters with a 90% high efficiency central gas furnace. The project included insulation on all six sides, windows, doors, high efficiency appliances, two ductless heat pumps, and 3.8 kW PV system. Upgrade costs and pre and post energy performance are summarized in the case study.

Click here to view the case study. Calle del Corte NZE - Google Drive


John Morgan Ohio Farmhouse Case Study

Updated 05/12/13 - John Morgan insulated the wall cavities and attic of his 1880 vintage southeastern Ohio farmhouse years ago. He achieved a deep energy retrofit through lifestyle choices, reduction of electric baseload, and replacement of his propane boiler with a ductless heat pump. His house is the 18th to meet the Thousand Home Challenge, and he does so without the addition of PV. 
Click here to download this PDF


Andrew Koh Massachusetts Case Study

Updated 05/1213 - Andrew Koh's home is the 15th to officially meet the Thousand Home Challenge. His family's 1960s Garrison Colonial home in Milton Massachusetts participated in National Grid's Deep Energy Retrofit pilot program  in 2010-11.The gas heated home uses an A. O. Smith Vertex water heater to supply the home's space and water heating needs.Thanks to A.O. Smith for the donation of this equipment. The project included a comprehensive enclosure retrofit, ventilation system, a 2.8 kW PV array, combined with an effort to reduce electrical baseload. The Building Science Corp case study is posted on their website:


Brownsberger Family Massachusetts Case Study

Updated 02/15/12 - Two households (three generations of Brownsbergers) sold their single family homes and renovated this two-family dwelling in Belmont, Massachusetts as part of the National Grid Deep Energy Retrofit Pilot. This project is the sixth to officially meet the Thousand Home Challenge, and the first project in Massachusetts to meet the THC.
Click here to download this PDF
Click here to download the case study prepared by Building Science Corporation for the U.S. DOE's Building America Program


Wayne and Diane Mackey Pennsylvania Case Study

Updated 01/31/12 - Located in Chambersburg, PA, this is the first home in Pennsylvania and the fifth home in North America to officially meet the Thousand Home Challenge.After meeting the 1000 Home Challenge, the Mackey's made additional improvements as well as installing additional PV capacity. At this point they are net zero, and simultaneously charge an electric vehicle. 
Click here to download this PDF Case Study
Click here to download Wayne Mackey's Public Presentation
Click here to download a graph of Energy Use & Cost Over Time
Click here to download a chart of Annual Energy Use (Pre and post project)
Click here to download an image of the house


George & Ellen Beeler California Case Study

Updated 03/26/11 - This 1940s home in Petaluma is the first home in California to meet the Thousand Home Challenge as part of the NorCal Collaborative. This project was completed in three stages, and incorporates a seismic retrofit. 
Click here to download this PDF



Ross Residence Massachusetts Case Study

Updated 01/16/13 - The Ross residence in Amherst, Massachusetts achieved net zero in their 1884 home. This project has been exporting electricity since it was renovated in 2011. It is the 8th home to officially meet the Thousand Home Challenge.They received the NESEA net zero energy home award.
Click here to download this PDF


Ward Lutz Ohio Net Positive Home

Updated 02/13/12 - This is one of the first homes in the United States and the first Ohio project to meet the Thousand Home Challenge. It is a net energy producer. Based in Urbana, Ohio, this 60 year-old home met the threshold allowance a year after work was completed. Since then the addition of a PV array and ductless heat pump have moved Ward Lutz’s home to become a net energy exporter.
Click here to download Case Study PDF
lick here to download Linda Wigington's presentation from July 2012 "Data, Not Dogma" event


Bill Turner Utah Case Study

Updated 02/24/14 - Located in the mountains of Utah, this staged project has made impressive reductions to date but still needs to cut energy use by half to meet the Thousand Home Challenge. It is a Thousand Home Challenge Candidate. Features include a major basement remediation to create livable space, significant reduction in air leakage, integrating insulation of a cathedral ceiling as part of re-roofing as well as greatly improved comfort and elimination of an infestation of critters. While this log cabin reduction project has some elements unique to its 8,000 heating degree days location, there are practical lessons appropriate to house foundations and roofs in many parts of the country. 
 Click here to download this PDF


Joanne Olson Wisconsin Case Study

Updated 03/26/11 - A case study from Viroqua, Wisconsin demonstrates the process and results from the first of a three-stage retrofit on the path to net-zero energy.
Click here to download this PDF


Sue and Gord Scale Case Study

Updated 12/03/10 - This PDF shows the Adolphustown Schoolhouse Deep Energy Retrofit in Greater Napanee, Ontario, Canada. This is the first Canadian project to participate in and to meet the Thousand Home Challenge.  This home heats with a masonry wood heater. No PV was needed to meet the Thousand Home Challenge.
  Click here to download this PDF


Richard Renner Case Study

Updated 06/05/10 - This PDF shows the Portland, Maine renovation of an abandoned brick building to a professional office and studio loft by architect and owner, Richard Renner. While not meeting the Thousand Home Challenge at this time, this project is an example of a substantial renovation that achieves exemplary energy performance and sustainability.
Click here to download this PDF


Jane Bindley Case Study

Updated 03/01/10 - This PDF shows the conversion of a New Hampshire 1970’s ranch home to a net zero energy producer. This project's energy use for the past three years meets the Thousand Home Challenge. It will officially meet the Thousand Home Challenge when the application is successfully completed.
Click here to download this PDF



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