All concerned with advancing Green Building Design should engage in the process of flushing out a definition for Zero-Net Energy Building (ZNEB) as a set of building design guidelines for architects and builders. Colleagues are beginning to recognize that NZEB is central to the future of our profession. Currently, there isn’t a definition. Furthermore, the measuring science doesn’t exist. The National Institute of Standards and Testing has been conducting conferences over the past 4 years in an effort to flush out a system. One concept under consideration is "Whole Building Metrics". I've drafted a definition on a website I've developed for this purpose. I've provided links to support my conclusions backed up by 3 years research. There are two pages on the website; the HOME page illustrates an example I designed of a Zero Energy Concept Building (ZECB) and the second page is a draft of my definition of ZECB. I welcome all interested in sustainable design to visit, review, and comment on my effort to help advance the cause. Here's the link https://sites.google.com/site/zeroe...lding/home

The referenced website states:
"The roof rack is pitched to 67 degrees per solar tilt formula for Cleveland (Latitude: 41°28′56″N) to minimize the angle of incidence between the incoming light, and photovoltaic panels, which absorb and convert power from the sun into electrical energy. These photo electric cells are mounted to solar trackers, which pivot the panels to increase the amount of energy produced, by automatically correcting orientation toward the sun, as the sun moves across the sky."

1.  The angle of 67 degrees is optimized for winter only, and is too steep for best overall annual performance. 

2.  The reference used to compute the tilt is widely used.  However, it does not include the effect of weather in computing the optimum tilt angle.  I think that the winter weather in Cleveland is much cloudier than the summer weather.  Therefore, better overall annual performance will be obtained by using a tilt angle favoring summertime collection, which would be MUCH flatter than 67 deg.  PVWatts (Version 2) includes weather factors and temperature effects on solar panel efficiency. 

3.  Using PVWatts, the optimum overall annual tilt angle is 30 deg. for Cleveland (compared to a latitude of 41.5 deg.), which produces an annual production of 1.141 kWh/kW DC rating, while the angle in the design of 67 deg. produces 0.95 kWh/kW DC rating, or 16.7% less than the optimum angle.

The goal of NZEB to generate at least the same amount of energy as buildings consume doesn’t solve the problem of how to construct buildings which are completely self sufficient. A more holistic approach is to reach beyond NZEB to Zero Energy Concept Building (ZECB). ZECB is a leap forward ahead of NZEB because Zero Energy Concept Building includes technology to purify waste water and improve indoor air quality by harnessing the power of Mother Nature to replenish these resources. ZECB addresses poor indoor air quality which has been linked to health problems, while at the same time applying natural processes defined as fixed-film ecology for waste water purification. With fixed-film ecology water is used and reused in diverse ways; continuously cycling through nature’s cleansing process through a series of wetland tanks which do double duty by scrubbing the indoor air through the process of photosynthesis. Photosynthesis is a natural charge particle technology that makes pollutants heavy causing them to drop out of the air which is the natural method of cleansing indoor air. For more about understanding this authors definition for ZECB click on this link https://sites.google.com/site/zeroe...ar-economy

I find the Living Building Challenge that requires post-construction monitoring/verification/rectification more compelling than any prescriptive approach to net-zero commercial construction.  They're still in single-digits of buildings that have passed, but that's definitely a non-zero number. 

I may be peeking in a the Bullitt Center in Seattle in the next couple of weeks (just for fun), but they have LBC certification in their sights.  It's a very different type of building/use than the LakeFront Station project, and perhaps a bit easier to design for.

I agree with Lee's assessment that using simple solar geometry tool won't result in an optimal tilt- local seasonal air clarity has a big effect.  And whatever season you're trying to optimize, and a winter-optimized tilt like this will take a hit in total annual performance.

I have a simple gauge of credibility and LBC flunks it. To qualify for LBC certification, a single family residence can be no larger than 4,575 square feet, or roughly twice as large as the average new construction in the US, and three times as large as the average new home in France. No surprises here: A green home is by definition a custom home. Custom home buyers do not build 2 bed/1 bath houses. Therefore, to take dead aim at sustainability in US housing would oblige green building consultants to shoot themselves in the foot.

But one can't ignore size in sustainability. The US and Europe are now competing with Brazil, China and India for all commodities of which, it seems, energy is a small problem because natural gas development in the U.S. In contrast to US electric rates, copper prices in 2010 were much higher than they were in 2006, at the height of the US housing boom. They are still higher today despite a global economic slowdown. Inflationary pressures on new construction are not easing, in other words, and it shows in the marketplace. http://switchboard.nrdc.org/blogs/kbenfield/us_home_size_preferences_final.html

Yes, that's a tree-hugger site, but economics is economics. The market is rationing commodities by the tried and true method of limiting sales to those who can afford to pay. Sustainability in this sense is builders asking themselves 'will this house sell?' We can quibble about whether the average house is shrinking. By most accounts, the >4000 SF market was crushed and has not recovered; its absence in the statistics would influence the mathematical average even if the typical new house has the same square footage as before. We can't quibble about costs. And green building won't become mainstream by catering to a dwindling niche.

I find the Living Building Challenge that requires post-construction monitoring/verification/rectification more compelling

Wow, that's certainly progressive. I can't help wondering if some of the concepts in there aren't markedly ahead of their time. For example, the phrase "the undemocratic ownership of water rights" seems to stick in my head....

green building won't become mainstream by catering to a dwindling niche.

Well, it might stay alive, which is better than disappearing entirely.

Recently, the median price of new construction was reported at $235K. I am going to grab a number from Lee Dodge and take some liberties with it by assuming that his $28K additional cost to go Net Zero might be, oh, $40K for new construction. I am wondering how long it will be until 20% of new home buyers are willing to spend $275K for a home they could otherwise get for $235K. That's a mortgage payment of $1,261/mo versus $1,476/mo; a difference of $215.

Am still waiting to see that page of "green" homes in the local real estate booklet.

If it does come down to a $215 difference per month, it becomes a no-brainer as you should save at least that much in energy bills. The real estate market will catch on when we have these houses UP and LIVED in. At this point the majority of people don't "get it" and won't until their friends are living in one. The people I'm building for and talking to want low heating bills, but really have very little concept of the difference they will experience in living in a superinsulated house.

Most of our customers want and get low fuel bills.

But more often than not, when a General gets involved, they get fancy tile, light fixtures and landscaping instead. You can't sell what they won't buy. It has been a niche market since I started under the Carter fiasco...sorry administration. Without gov't. intervention you will not build the Green Usonian for Everyman.

Posted By ICFHybrid on 24 Jul 2012 10:57 AM

...snip...

Recently, the median price of new construction was reported at $235K. I am going to grab a number from Lee Dodge and take some liberties with it by assuming that his $28K additional cost to go Net Zero might be, oh, $40K for new construction. I am wondering how long it will be until 20% of new home buyers are willing to spend $275K for a home they could otherwise get for $235K. That's a mortgage payment of $1,261/mo versus $1,476/mo; a difference of $215.

...snip...

The $28K additional cost was for modifying a new home design in 2010, so it should be a similar cost today.  Some of that $28K was for cosmetic improvements (wood versus vinyl windows), so it should be possible to reduce that amount to say $25K.  The home is located in climate zone 6, and the standard insulation package before upgrades was to meet the IECC 2006 standards for climate zone 6, the county standards in place at the time of construction.  Three caveats: (1) the builder's standard package homes are also well built in terms of having low air infiltration, (2) house has one occupant, so net-zero with more occupants would require expanding solar PV system by maybe $1000 to $2000, (3) climate is ideal for solar passive, thermal, and PV.  So maybe the $40K might be a good number for a more general case.     

toddm-

I agree with your thoughts that building oversized homes generally runs counter to the idea of sustainability. I am not sure that I agree with your statement that "A green home is by definition a custom home." My home does not qualify as a green home in many ways, but it is a net-zero source energy home, and it is NOT a custom home, but rather a standard production home with a few modifications in the design phase. This approach dramatically reduces costs. The builder does include a number of green features in all his standard production homes, so maybe my home qualifies as "pale green!"

it becomes a no-brainer as you should save at least that much in energy bills.

Maybe. Locales and situations can differ. There might be additional hassles in green or energy saving construction like closing shutters or washing solar panels or something. A lot of people have a hard time understanding their run of the mill gas furnace and changing the filters routinely.

the majority of people don't "get it" and won't until their friends are living in one

Yeah, I hope it works. Unfortunately, as with everything else, one horror story can eclipse ten successes. More so with the large number of naysayers who are unwilling to change or are irrationally fearful and want to pan everything new or unfamiliar. On the good side, I would conservatively estimate that HALF of the people who saw my minisplits in operation are going to get a new system in the next year or two. Some of them weren't even thinking about re-equipping their home. Had to chuckle when the sparkies came down off the roof holding their clamping meters and exclaiming about the low power draws. They'll be getting minisplits.

Posted By BadgerBoilerMN on 24 Jul 2012 12:18 PM
Most of our customers want and get low fuel bills.

But more often than not, when a General gets involved, they get fancy tile, light fixtures and landscaping instead. You can't sell what they won't buy. It has been a niche market since I started under the Carter fiasco...sorry administration. Without gov't. intervention you will not build the Green Usonian for Everyman.

Without government intervention, we don't have an interstate highway system, or any highway system for that matter.  Nor do we have city water, city sewers, nuclear power, police, courts, armed forces, and a huge list of other things that we take for granted.  I personally have greatly benefited from the federal government spending a few bucks to develop software tools like RESFEN, REScheck, BEopt, and DOE2 that allow any ol' Joe to develop a low-energy consumption, comfortable house.  Most folks like goverment help for their pet projects, but call it "intervention" when it does not fall into their list of pet projects.   

And I benefited from the Carter administration putting the first fuel mileage standards on cars.  If you remember, those standards followed the time that the Chevy Corvair was a tiny economy car that got 16 or 18 mpg while spewing out emissions that were 100 times greater than currently allowed.  Now we expect much better than that in a Caddy!  Look at a plot of the energy use in the U.S. and you can see the first change in slope of the energy curve in modern times after the CAFE standards were imposed.     

So maybe the $40K might be a good number for a more general case.

Yeah, I also was thinking that your place might have been smaller than the median which I used for the illustration, so I bumped it a bit.

I am not sure that I agree with your statement that "A green home is by definition a custom home."

Don't let all the other concepts of "green" cloud the issue. Energy use during the lifetime of the structure is the biggest and most important issue in green building. I think Net Zero makes you well-qualified to grab the green moniker. With builders calling the inclusion of Energy Star appliances and a little bamboo "custom" or "green", it's a long shot not to consider your modifications substantially custom.

Not to argue semantics, Lee, but net zero is bright green in my book, and your home, production roots aside, would not be so if you hadn't made an individual (custom) effort.

Sad to say, most home buyers don't care. In Britain, sellers and renters of residential real estate must show an energy performance certificate to prospects that rates its efficiency in seven categories and lists the remediations necessary to improve it. Reports of the impact are mixed in the few studies looking at consumer behavior. This study says that buyers in 2008. a year after implementation, knew what an EPC was but didn't change their minds based on its results or even use it in negotiations. http://www.cibse.org/content/cibsesymposium2011/Paper108.pdf

Even so, there's no regulation that would get more bang for the green building buck than this. Interest in auto fuel economy waxes and wanes with the price of gas but everybody knows where they stand thanks to EPA mileage tests.

I doubt that Congress would pass a US version of EPCs however. Realtors and lenders would line up six across to tell their reps that disclosure is bad for bidness. Lenders in particular would howl about paying for audits that could make foreclosed properties harder to sell.

Imagine yourself a Realtor or a Builder's Sales Rep. You've got all the regular sales resistance; style, size, location, layout, color, etc., and now you've got to deal with the fact it's $40K more because it's green. Assuming that only 10% of the population will pony up for a green place, who wants to hear 9 TIMES more "NO, I don't think so"? That could get old fast. I suppose you could assume that folks who ARE willing are going to hotfoot it across town to get your offering, but .......

the people who use this forum are in the forefront of a long term change in the way houses are built in this country. It won't happen quickly. I started putting radon vents in houses in the 80's, before most buyers had heard of the gas. Nowadays all buyers get a home inspection and most inspectors test for radon.

The price of heating fuel is rising. Someday, people like the ones we talked to a few weeks ago, who have a 1400 SF house which now costs $4000 per year to heat, will look at the heating costs of houses before buying them, and the ones that they cannot afford to heat will be passed over. It won't happen all of a sudden in 2013 or 2015, but it will happen and the houses that people on this forum are building will be the ones which will demand a premium.

And we need to stop thinking in terms of "green". That term has been co-opted so that it is now meaningless. The house of the future is Lee Dodge's - the "standard production home with a few modifications" that is, nevertheless, net zero. the bamboo floors will be ripped up in 20 years but the envelope will work for decades. His is, I believe, the house of the future.

It won't happen all of a sudden in 2013 or 2015,

It could happen overnight. All it takes is a little upset in the energy delivery chain....

Another important factor is that a specific house design that works well in Florida might not work well in Minnesota. Different techniques and building materials have to be employed for an areas specific climate and availability. Some energy efficient homes don't even have an A/C, well that concept won't work in Phoenix, AZ or other desert southwest environments.

There is no "one" specific way to build a home and have it be energy efficient. We here in America like individualism and self expression, trying to make people chose one specific design/layout of a home will not work. People don't want to live in drab & boring rectangular homes no matter how energy efficient they are. This has been seen in the automobile industry. When energy efficient vehicles were designed to look like eggs on wheels, they did NOT sell too well. When the energy efficient vehicle was designed to have sexier lines and curves, the vehicle sold.

So whether it is wood frame, SIPs, ICF, SCIPs, or whatever method, we need to embrace ALL designs that utilize energy efficiency and long term sustainability. In this endeavor will must also not forget that the aesthetics of a homes design is important. I believe that in some peoples haste to build a energy efficient home they overlook aesthetics as being an important factor in getting people to consider efficient homes. In the auto industry this was seen when engineers & scientists who were merely focused on efficiency SHOULD NOT be allowed to design what the vehicle will look like. Leave that to the designers who have a creative flare, not the boring scientists.

We must put all options and designs on the table for Americans to chose based on their individual style and tastes and geographical locations. The minute they say it MUST be this method or it MUST look like that, you have alienated 95% of Americans and your cause has failed. Individualism and expression is part of what makes us humans and Americans. Unfortunately some of the zealous and egotistical people in the green movement have killed the cause because of that.

Mr. Dodge paints with a wide brush.

The question is really one of cost. I am stingy, but practical. They just shut down a windmill plant in southern Minnesota after the a company - based in India - ran out of gov't. - read taxpayer - money.

Energy conservation has to have a rational goal with a reasonable and honest rate of return. My pet project is creating comfort at a reasonable cost. Some want to save the planet and I say cut your fuel bill in half. There are many ways to achieve this goal, the best of which follow market forces devoid of "special interests". Economy is the natural result of the free market. If solar panels cost too much or won't save fuel, or can't be economical because the cost of natural gas is too low, so be it.

Sighting CO2 as a global threat, they lost me.

"The price of heating fuel is rising." Really?

http://www.eia.gov/forecasts/steo/

I have been selling high efficiency since the 1987, the market for the most part has not grown. It costs a lot to be green and most folks just want a "nice" house. Literally the last place that look, if at all, is in the mechanical room. My clients tend to be a little older, definitely frugal and well educated planning to be comfortable in their old age regardless of future fuel prices. If their needs happen to follow the "science de jour" all the better. If the gov't. will take less out of their soon-to-end income, better!

I am not against mutual cooperation, but think intimidation and dictatorial mandates are counterproductive in the long run.

Interstate highways are a pour example of "good" government, as they were built strategically in anticipation of war and the common defense (unquestionably a proper use of government).

Comparing a country like Britain (zero natural resources) to the US, with a 500 year supply, stretches credibility and validity. Most people don't care about saving fuel or the planet for that matter rather their own dollars or pounds as it were. If you want to save fuel and the planet you have to sell the personal benefits the most immediate of which are independence, low fuel bills and - yet to be seen - a hedge against higher fuel prices.

"Unfortunately some of the zealous and egotistical people in the green movement have killed the cause because of that." Amen.