The Power Haus -22 HERS Index Home

The ‘Power Haus’ by Josh Wynne Construction in Sarasota, Florida has achieved the lowest HERS rating on record in the U.S., a negative 22, with an elegant, well-crafted design. Earning 118 LEED points the home is just shy of also becoming the highest scoring LEED home in the country by 1.5 points to the Helenowski Residence in Chicago, which holds the highest known score at 119.5.

With a negative HERS score, the Power Haus is producing more energy than it consumes on a yearly net basis.  The home has a 14.2 kW Uni-Solar Flex-Lite amorphous silica (peel and stick) array to bring it into so-called climate positive territory. Not considering the solar, Power Haus would still achieve a 42 HERS index which is noteworthy in and of itself. They were able to achieve such energy savings through a variety of passive and technological applications.

Power Haus is carefully situated within large existing trees, of which shadow lines were studied in conjunction with large 4’ eaves to provide protection from the Florida sun.  Importance was paid to the ability to open the home to the outdoors and capture the westerly breeze.

To assist in the natural ventilation the house is equipped with ceiling fans, including one 8’ in diameter in the great room, and large expanses of operable windows and doors.  An independent dehumidification was installed to counter the Florida humidity and increase the number of natural ventilation days.

The building envelop is a standard CMU construction wall type with foam insulation filled within the open cells of the CMU block (R-15) and VR-Plus II permeable radiant barrier (R-7.2) to fight against thermal bridging.  Closed cell bio-based R-30 spray foam insulation was applied exterior of the moisture barrier to allow for the elegant interior tongue and groove ceiling and glu-lam beams.

With durability an important goal the builder pursued impact resistant, low-e, argon filled windows from Jeld Wen with a 0.3 SHGC and 0.19 U-value.

Technological applications include 21 SEER Carrier Infinity HVAC system, Eternal gas tankless hybrid water heater, Energy Star appliances and 100% LED lighting.  Power Haus is fully automated with real-time energy production and lighting controls available on an iPad or iPhone through Elan Home Systems.  In addition to energy efficiency, the home shows a commitment to sustainability with polished concrete floors, clay wall finish, and reclaimed cypress or FSC wood throughout the house.

Outside the green home, landscape irrigation is eliminated through the use of a native and drought tolerant plant palate.  Rainwater is captured from 100% of the roof area and feeds a 6,000-gallon cistern for future use interior (once the code catches up and allows filtered rainwater at the tap) and is currently used within the horse stables.  Interior water use is reduced through low-flow fixtures and dual-flush toilets fed with greywater.

Josh Wynne has a great history of producing sustainable homes, previously designing and constructing the former highest scoring LEED home, Codding Cottage.  However, it is not about scoring LEED points, Josh stated, but about setting strong environmental goals and delivering a quality product.  ‘Price Up’ next for Josh Wynne Construction is a new construction home with a -50 HERS Index — stay tuned for updates.

It should be noted that The Power Haus also scored the highest rating possible through NAHB Green (Emerald) and Florida Green Building Coalition (Platinum), in addition to LEED Platinum certification.

Photo Credit:  Matt McCourney.


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  • http://yourhoustonhomeinspector.com Frank Schulte-Ladbeck

    Congratulations to the builder on such an achievement, and what a wonderful design.

  • Bill60546

     Cost per square foot?

  • Josh

     Thanks Mark. The cost per square foot is being withheld at the owners’ request. It falls into the $1-1.5 million category in several awards categories. I have a project on the books that will outscore and outperform this one for under $150,000. Stay tuned.

    • Jeremiah

      Can’t wait to see that design Josh. Cheers.

  • Sea Wolf

     If this is the kind of house LEED leads to, we’re doomed.

    • Jeremiah

       Wolf, are you talking about design or price? Price – yeah I’m with you. Design, not so much. I’m sure I, or any other architect with a little talent and imagination could design something similar for an affordable price tag.

      • Josh

        Consider this home relative to its non-LEED counterpart rather than against your idyllic vision. The truth is that my client was going to build something bigger and less sustainable. This is 1000x more eco-conscious than the alternative. If you wish to make ANY impact you cannot aim squarely at your perception of a perfect home, but rather at substantial improvements. If I was only willing to build what I perceive to be responsible I would build for no one and therefore make no positive influence. Consider this home a prototype. It is a way to test what is is coming soon. Without this home, I could not have fully understood what is necessary to do and to sell what I am building now. Off the grid from power, rainwater to tap, family living in under 1200ft and zero affect on permeability……for under $150k in one of America’s most expensive cities. 

        • Kevmon

          Josh.  I hear you- we build super efficient houses too, including passive houses, and sometimes you take a less than ideal job knowing that it would have a much greater impact if you didn’t take it on.  Honestly, you give me a goal to shoot for.  This is good stuff.

      • Sea Wolf

        Neither.  I’m talking about a size of house, level of material use, swimming pool, lawn, and location (lacking density, it would appear), even posture, if you will, the notion implicit in this house that someone can have all of this and so long as it’s -22 HERS, it’s all good.

  • Anonymous

     You state in the article you utilize greywater for toilet flushing…what system did you use?  

    • Josh

       Brac is the only system approved in our municipality for gray water reclamation.

      • Anonymous

        Hi Josh, Have you ever heard of Water Legacy? It is a US manufactured system from Colorado. the system is UPC and IAPMO approved and is viewable at http://www.waterlegacy.com. I am their blogger and marketing person so I frequently seek out who is installing and using greywater recycling systems.

        Thanks,

        Chris Vail

  • http://www.yellowbluedesigns.com Jessica Janes

    Good job raising the bar by lowering the HERS score.  A bit ironic.  Anyhow, it is a huge accomplishment.

  • Ecd Fann

    Picasa web pics of Florida International job that ecd.fan posts here are old pictures (NOT updated)of an improper installation where non-certified-roofers [university maintenance staff] failed to follow proper installation procedures and manufacturer’s instructions and guidelines, as proven by their hurried instal time.Notice the improper horizontal layout against a vertical slope.Also obvious surface was not prepped to manufacturer’s specs.ecd.fan is my incompetent, disengenuous, mal-adjusted siamese twin.  Ignore it.

  • http://www.facebook.com/Brett.loves.sustainability Brett Little

    Josh.

    What product is this “Closed cell bio-based R-30 spray foam insulation “

    • http://www.joshwynneconstruction.com Josh

      Brett- ‘Bio-Based’ is the product manufacturer.

      Sea Wolf- From an ideal perspective I see and share your point of view. In the real world, people build homes in the woods. In this case the client plays polo for a living. He lived in an urban district and commuted to the Polo Club daily to play. Now he does not commute. This is a good thing. I was penalized nonetheless. This area is not a greenfield of 50 buildable lots but rather an agricultural community and one buildable lot by our zoning code. As to the pool, size, etc… much like cost, people will have what they choose. The point is not for everyone to live in 900sqft homes but for everyone to build smaller, more efficient homes than they would have otherwise. If you put this home on the bell curve it should be MORE impressive than a 900 sqft box in an urban neighborhood made from poop and aluminum cans. I was able to make EVERY single aspect of this larger than necessary, large lot, pool home more responsible in every way imaginable in spite of what you see as short comings. That ingenuity will translate into what you see as an ideal dwelling soon enough. My Codding Cottage project certified in 2009 was highest scoring LEED home in the US at completion. It is 2500 sqft on a 4900 sqft lot in an urban core designated an historic district. It had a HERS of 27 with only a 2kw PV system. I had to meet an architectural standard on that home but I’m sure you won’t appreciate it either.

  • Robert

    My wife brings this up anytime I show her a article on a innovative green home and that is how can you call house green if you have a pool. We live in Austin Texas and water is becoming a big problem so my question is should the score of the home include all aspects of the home,energy,landscaping and if you have a pool and how much water the pool uses?

    • Josh Wynne

      We average 54″ of rainfall annually. This pool’s autofill is connected to the 6000 gallon cistern. The pool water is no issue here. It could be a regional consideration though.

      Our regional standard (FGBC) of which this home is Platinum certified, does have pool requirements as prerequisites such as: no chlorine, two speeds, etc.

      All programs that this home is certified under also weigh in landscape as well.  Without the pool, this home has a HERS index of -35. 

  • Richardotiswilson

    Congratulations on a beautiful house.  I am about to break ground on a very similar home in central Florida.  I am interested in the electrical system and in particular the monitoring of the different system through the Elan system.  Was it cost effective to monitor all the systems, or was it a decision made by the owners.  Also how did it effect the Leed points, did you end up going above and beyond the Leed requirements in the categories that it effects.
    Our home is being constructed with the Aercon blocks, highly reflective metal roof, a 7000 gal cistern, 14 kw solar system, an aquaculture pond, and of course a high SEER HVAC.  We have no grey water access and are hooked up to city sewer so the will not allow us to use the cistern for potable water.  We are looking at the lighting right now and starting to weigh the differences between LED, CFL, and Low Voltage.  The house was designed by Phil Kean Design and being built by E2 homes.

  • Lcapa

    Josh:  When will you present more information on your $150,000 project that is in the works?  I think we would all be interested in something at this price range!  Beautiful house.  Thank you.

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