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.


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.
Link to Sonoma Retrofit House 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:

Massachusetts Super Insulation Project
Community Land Trust Association of West Marin
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 our projects for committing the time to share their stories!



Ward Lutz Ohio Net Positive Home

(Updated 08-19-2020) - 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, averaging 4.2 surplus kWh/day since November 2010. Some discussion and additiona performance information is posted on the Home Energy Pros, Thousand Home Challenge Group.As an experiment, this home has the outdoor unit of the ductless heat pump located in the unconditioned crawl space. Energy use, temperature, and relative humidity data for both the heating and cooling seasons is summarized  in several of the spreadsheets below. 

Click here to download Case Study PDF

Click here to download excel spreadsheet, avg. daily energy production, use, and net Nov 2010 to June 30, 2014 

Click here to download Linda Wigington's presentation from July 2012 "Data, Not Dogma" event

Click here to download the excel spreadsheet, energy use & production by month over 4-year period

Click here to download the excel spreadsheet of June 2014 energy use, temperature, & RH (inside, outside, & crawl space)

Click here to download the excel spreadsheet of 2013-2014 heating energy use, temperature, & RH with DHP and pellet stove (inside, outside, & crawl space)

NEW! Click here to view the energy summary by year (2012-2019)

Wayne and Diane Mackey Pennsylvania Case Study

(Updated 10-28-2017) - 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 the 5-year (2012-2017) Summary of Savings & Income

Click here to download Home Energy Score Report: 10 out of 10!

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

Midori Haus, Santa Cruz, California

(Updated 07-20-2017) - The 22nd house to meet the Thousand Home Challenge is the home of Kurt Hurley and Chie Kawahara, a California bungalow originally built in 1922. The home was renovated in 2012 with a focus on significant energy reduction while restoring the charm of Arts and Crafts aesthetics. Their renovation was driven by Passive House principles, and the home's Passive House certification marked the worldwide millionth square meter of certified projects. This 1,569 ft2home used only 4,396 kWh/year withour using PV to offset electricity use. The couple hosts several public tours throughout the year and a forthcoming book describes their journey.

Click to see website for blogs, home tours, and book information

Maine Lake Science Center --  Log Cabin Transformed!

(Updated 7-08-2016) Explore the transformation of an abandoned Maine log house to the high performance Lake Science Center. The Lakes Environmental Association (LEA) embraced the challenge of creating the LSC, complete with a conference center, laboratory facilities, office space, educational space, and residential functions for visiting researchers.Among the many significant upgrades, the LEA provided insulation to the walls, roofs, and foundations and replaced old heating, domestic hot water, and ventilation equipment with up-to-date systems. An application to become a candidate for the Maine 1000 Home Challenge is in progress. Stay tuned to see if this project comes in better than the 50% Milestone of 18,500 kWh (total site energy) in this 3,500 square foot building.

Click here to download BBBD Conference PDF Presentation  (2-03-2016, Burlington, VT, William Turner & Peter Lowell)

Click here to download the PDF  (case study from 8-20-2015)

Maine Antique Rehab & Staged Retrofit

(Updated 08-07-2015)  This is the 1st home in Maine and the 27th project to meet the Thosuand Home Challenge. 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. Concern for indoor air quality and durability have been considerations since the beginning. 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 ductless heat pumps to further offset wood use.

Click to download this pdf

Click here to download the short PDF

Deep Energy Reduction Renovation of the Golden Acorn Ferret Cabilow

(Updated 07-09-2016) This DIY DER of a 1929 miner's cabin in the Colorado mountains is our first project from Colorado.  As an ongoing work-in-progress, it is a Thousand Home Challenge Candidate.  Since 2011 it has achieved a 51% reduction in site energy usage through the use of attic and wall insulation upgrades, air sealing, window replacements, and solar PV, as well as occupant efficiency strategies.  A very-low-budget renovation, it makes extensive use of salvaged materials to keep costs affordable.  

Click here to download Energy Reduction Case Study PDF 

Click here to download the March 2016 Progress Report 

Click here for Pursuit of Carbon Neutrality (PDF) 

Click here for the Cabin's Story (PDF) 

Richard Renner Portland Maine Loft Case Study

(Updated 08-06-2015) - Explore 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 the time it was done, this project is an example of a substantial renovation that achieves exemplary energy performance and sustainability.

Click here to download this PDF

Click here to download the short PDF

25th Project to Officially Meet the 1000 Home Challenge!

The Energy+ Household – Bay Area, California

(Updated 03-05-2015) - Over the last several years the Ghosh family has retrofitted their 2,170 ft2 house with a host of technological solutions. This project exemplifies the integration of efficiency, electrification, on-site electricity generation, and the use of electric vehicles as a way to substantially reduce a household’s carbon footprint. The family of four has zero energy bills! That is, in day-to-day living, the Ghosh family pays zero electricity bills, zero natural gas bills, and zero gasoline bills. They use no propane or firewood. The family meets the energy needs of its all-electric home through a 11 kW PV array. The solar system generates a net surplus which has been used to operate two cars for commuting, chores, and occasional weekend trips. This single-family home was built in 1997; in 2010 it consumed 600 therms of natural gas and 5,500 kWh of electricity (23,000 kWh site energy). Current household energy use, without the contribution of the PV generations is estimated to be <10,000 kWh. The average site energy use of a single-family California home is 20,000 kWh. 

Click here to download Case Study PDF

Bergamaschi/Soo Hoo Residence, Oakland, California 

(Updated 03-10-2015) - In 2011, this home became the 2nd in California, and the 5th in North America to officially meet the Thousand Home Challenge. The project documents that it is possible to substantially reduce energy use in an eleven-year-old California home, one that was built to the California Title 24 Energy Code. It provides an example of how the integration of lifestyle, renewables, and close attention to both electric and gas baseload can contribute to a home with very low energy use in California.  

Click here to access the PDF and audio of a webinar featuring this project.

Monahan Zero Energy Home Case Study

(Updated 01-07-2015) - 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 studyCalle del Corte NZE - Google Drive

Click here to view the video of the case study presentation given at the NMSEA conference

John Morgan Ohio Farmhouse Case Study

(Updated 01-07-2015) - 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

John Livermore Case Study

 (Updated 6-27-2014) – This is the 24th project to officially meet the 1000 Home Challenge. 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.

Click here to download this PDF

Bill Turner Utah Case Study

(Updated 03-13-2014) - 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

The House on Hummingbird Hill, Salinas, California

(Updated 12-04-2013) - 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

Andrew Koh Massachusetts Case Study

(Updated 05-12-2013) - 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. 

Brownsberger Family Massachusetts Case Study

(Updated 02-15-2012) - 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

George & Ellen Beeler California Case Study

(Updated 03-26-2011) - 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 01-16-2013) - 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

Joanne Olson Wisconsin Case Study

(Updated 03-26-2011) - 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 12-03-2013) - 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

Jane Bindley Case Study

(Updated 03-01-2010) - 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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