My net-zero home research, part 3

Okay, last week I reviewed the objectives and goal of my research.  Just to put it into context–this research was part of the requirements to earning my doctor of philosophy from the University of Massachusetts Lowell aka UML.  My adviser was Professor (now emeritus) John Duffy, the coordinator of the solar energy program at UML. Okay, now on to a small excerpt from the literature search I performed…

I found several papers presenting results on research on net-zero and near net-zero homes located outside of New England. One of these was by Danny Parker of the Florida Solar Energy Center, entitled “Very Low Energy Homes in the United States: Perspectives on Performance from Measured Data” (Energy and Buildings, 2008). Parker provides a concise review of low-energy homes in the US, ranging from individual units built strictly for research into energy efficiency to large subdivisions of energy efficient homes with installed PV systems.  Parker compares the cost effectiveness of homes built in twelve areas of the US, all of which were built since 1998, and for which data on energy use, consumption, and cost was systematically collected for at least a year.  The table below lists some basic characteristics for these homes.  Parker’s research indicated “…greater investment in conservation should be a prerequisite to installation of solar water heating and solar electricity in Near Zero Energy Homes.”  Note that none of the homes he investigated were in the New England region.

Homes studied in the paper by Danny Parker

Location

Number of Homes

Year Built

Notes

Lakeland, FL

1

1998

Used 92% less grid energy than “control” house

Washington, DC

1

2001

Livermore, CA

1

2002

Lenoir City, TN

5

2002-2005

Habitat for Humanity homes built by Oak Ridge National Lab

Tucson, AZ

1

2003

Wheat Ridge, CO

1

2005

Habitat for Humanity home built by NREL

Sacramento, CA

95

2004

Homes used 54% less grid electricity than “standard” subdivision homes

Urbana, IL

1

2003

First Passive House built in US

I found several other papers that reviewed the performance of these types of homes in other states, including Nevada, Florida, Colorado and California.  However, at least in 2011 when I was performing this search, I could find only three published studies on net-zero and/or near net-zero energy homes in New England.   The first was a yearlong study by Marc Rosenbaum, PE, entitled “To Achieve Net-Zero You’ve Got to Live Net-Zero (Solar Today, 2011) on eight small homes on Martha’s Vineyard that were designed to be affordable NZEHs. These homes ranged in size from 1251 to 1447 sq. ft., and were built by the Island Housing Trust with permanent affordability restrictions (meaning that they would have to remain affordable, even on super-elite Martha’s Vineyard). After the first year of occupancy, two of the eight homes were net-zero, with three others within 25% of net-zero, and the remaining three were not even close. Rosenbaum concluded that achieving net-zero appeared to be dependent more on occupant behavior than building design, since the eight homes were more or less identical in terms of location, building specifications, and energy production potential.

The second study, also for one year, was on 13 NNZEHs built as a moderate-income development in Greenfield, MA entitled “RDI’s Wisdom Way Solar Village Final Report” (Steve Winter Associates, Inc., 2011). This study focused on the annual energy cost of these homes, specifically built to be affordable to buy and operate, by Rural Development, Inc. The results were promising, as the average annual energy cost for the 13 homes (ranging in size from 1,137 to 1,773 sq. ft.) was just $337. (Yes, that’s correct and not a typo!  New Englanders spending less than $400 a YEAR on all their energy. My research had similarly amazing findings. Saving money on energy bills, as you’ll see, is one of the biggest advantages to owning one of these homes!)  As in the Vineyard study, occupant behavior was the dominant reason for the range in annual energy cost (mostly in natural gas usage for heating).

The third study was on a single 3-bedroom, two-story house built in Townsend, MA, entitled “New England Net Zero Production Houses” (Bergey & Ueno, 2011). This home was one of several net-zero energy homes built by a local builder (Transformations, Inc.) as part of a 20 home development. This builder’s goal is build affordable, net-zero energy production homes that look very much like any other New England house. During the year in which it was studied, this home came close to being net-zero, with just 1000 kWh net consumed.  The builder designed this home to achieve a Home Energy Rating System (HERS) index of 40, and then added a PV system to bring the home to a HERS index of 0, i.e. net-zero.

The homes from these last three studies show that NZEH and NNZEHs are quite possible in New England.  However, in all cases, the homes studied were very homogeneous in design, still relatively small by New England standards, and all in Massachusetts. Thus, they did not show how a group of more diverse New England NZEHs (including design, size, system components and geographic location) would perform.  This was encouraging to me, since that meant my research project–as far as I could tell–would be the first to study a range of net-zero and near net-zero homes in New England.  Thus, I hoped that I my work would not only get me a Ph D, but would actually yield important new data on the performance of these homes.  I’m happy to say, now that it is finished, I have that data.

Next time, I’ll start describing the 20 homes and their occupants who participated in my research.

Walter

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4 thoughts on “My net-zero home research, part 3

    • Hoho, good catch Paul! I’d like to say that I deliberately misnumbered my posts, just to see if anyone was paying attention. Evidently you were! However, I can’t claim any intentional skipping of post 3. I have now renumbered what was originally post 4, changing it to 3. Today’s post is now post 4. Just goes to show that even someone with a Ph D sometimes can’t count to 4…I blame my dog for distracting me.

  1. hi Walter, This is a great start, but looking for information that quantifies the results vs. predicted values for energy consumption Is that part of your research? IF so, could you send me that report-as it may be larger than a blog can carry. Thanks in advance. Cheers David

    • Actually Paul, fully one-third of my thesis is devoted to analyzing the energy performance of these homes, which includes comparing them to modeled performance. I develop my own models in fact, as well as compare their performance against model results given to me by the homeowners, calculated by their architects or engineers in the design phase. I don’t have a separate report I can just email, unfortunately. However–I am planning to publish the energy performance vs. modeled results in the peer-reviewed journal “Energy and Buildings”. I am in the midst of revising my submission based on the reviewers’ comments, and will be re-submitting in early August. Hopefully, that paper will be published on-line soon after that. If you can’t wait for that paper (which is relatively concise at 20 pages), then go to the website I mention in my latest blog posting. The home page has a link to my thesis, in which you’ll find all my results.

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