Category: low energy solutions

26
Jun
2017

Zero energy homes | the Passivhaus approach to reducing energy bills in homes

The focus of this discussion is achieving a zero energy home through the Passivhaus approach.

True or false – adding insulation has diminishing returns? True, doubling the thickness of a roof insulation doubles the cost while halving the heat loss/gain, and half of a half is a quarter and half of that an eighth…. So, “How low should we go?” as some have asked. The idea behind the Passivhaus program, developed in Germany, is to break through the cost barrier by sealing and insulating the bejesus out of an envelope till the need for mechanical equipment is eliminated (apart from fresh-air delivery).   What about the applicability of the system to the mid-Atlantic region? According to Galen Staengl, Passivhaus-certified energy consultant, “It’s still an open question as to where the cost/performance balance is struck in in our region where cooling and dehumidification are also required.” Even with the adaptability of the approach to different climates still being explored, the program offers valuable insight into how we might crack the zero energy code.

The Passivhaus program is performance-based. To achieve the 4.7 kBtu/ft/yr goal, recommended R-values for walls are R-40, for roofs, R-60. At the Hickory Hall project at the College of Emory & Henry in Virginia consulting engineer Staengl says this is achieved with a wall system comprised of 2×6 studs with cellulose insulation and 2 1/2″ of EPS insulation outside of the sheathing – all building techniques well understood by contractors and resulting in a cost increase of only 5%. The Contracting firm of Structures Design Build, located in Roanoke, Virginia alters the DNA of the typical wall section by adding a modified Larsen truss outside of the studs and sheathing. The truss, truss joists turned on their side with the webbing removed, is filled with cellulose.

The Passivhaus approach doesn’t stop at the envelope. In the US, where the climate varies from hot to cold and somewhere in between, and where some parts see enough humidity to wilt Blanche Dubois’ curls, energy-efficient lighting and equipment, especially hot water heating, need to be addressed.   And of course, all the other aspects we’ve discussed above are thrown into the stone soup of the Passivhaus approach resulting in a HERS rating of between 20-30.

One of the challenges of the application of Passivhaus approach in the US is availability of cost-friendly materials. Triple-pane windows, a must for the approach, are just beginning to show up in the marketplace. Happily many of the major window manufacturers are getting on-board and Marvin, Pella and Milgard all offer triple pane options. In Europe where energy codes now mandate a Passivhaus approach, triple pane windows have become the norm — and costs are lower than for double pane — the more stringent codes in Europe are affecting a radical change in the marketplace.

In addition to the significant energy savings of the Passivhaus approach, consider the indoor climate. A recently completed home in Virginia Beach uses triple pane windows and the temperature of the glass is ten degrees warmer in the winter. The increased

Triple Pane Windows

Triple pane windows in this home reduce energy bills and increase comfort. The temperature at the windows is 10 degrees warmer in the winter.

comfort associated with a well-designed envelope is palpable and a nice side benefit to reduced energy bills.

29
Aug
2016

affordable green buildings: lessons from the Make It Right Homes

To understand how to build affordable green buildings, it’s useful to look toward low-income communities where these strategies are being applied at scale, where costs and paybacks are being measured. The Make It Right (MIR) Foundation is just such a test-bed community – a Petri dish for our examination. Make It Right builds affordable green homes and buildings and began by with the reconstruction of the Lower 9th Ward in New Orleans after Hurricane Katrina. Started by Brad Pitt in 2007, Make it Right buildings are LEED Platinum certified and inspired by Cradle to Cradle thinking. The MIR Foundation’s primary goal is to change the building industry by implementing green building strategies that is affordable to all.   MIR utilizes an array of methods:

  •  Advanced framing to reduce material and labor costs: studs at 24″ on center or the use of structural insulated panels are some of the techniques used (R-25 walls, R-33 roof, R-13 subfloor).  Less labor means more affordable.  Less materials means more green.
  • Interior finishes that are low or no off-gassing make for healthy living.
  • Green electrical through wireless electrical system (Verve).  The higher cost of the system is offset by lower cost for installation.
  • A high velocity air-conditioning system reduces size of duct/trunk lines which can then run in the structure, saving on structural and finishing costs.
  • Well insulated walls and air tight buildings reduce energy loads and therfore long-term operational costs.  Green Insulation such as spray foam and recycled denim insulation are used.
  • Low-flow faucets, shower heads and dual flush toilets reduce water consumption.
  • Cisterns for irrigation also reduce water usage.
  • Tankless water heaters means no tanks — water is heated only when needed which reduces energy costs.
  • 4.25 KW solar array (grid-tied/net-metered) uses the sun to generate energy for the buildings.
  • Building Information Management (BIM) allows the organization to analyze and reconfigure the building DNA as it evolves.  BIM provides feedback to increase the efficiencies to make their buildings ever more affordable and green.

The typical HERS (Home Energy Rating System) of a home is 100. The typical Make it Right home has a HERS rating of 15-20, or an 80% reduction in energy use over the typical. For $150/SF, including solar panels (of which a portion receives a government tax goodies), this is a remarkable feat.

02
Aug
2016

Modern Green Virginia Beach House Tour

Tour of soon-to-be-finished modern green Virginia beach house on August 11th at 6:00 PM.  Meet at the Cavalier Golf and Yacht Club (parking lot nearest the clubhouse) at 1052 Cardinal Road, Virginia Beach, VA.  Attendance limited.  Please RSVP to aewing@hays-ewing.com.

House features:

Superinsulated and designed to meet Passivhaus standards, triple glazed windows, Huber Zip system, FSC certified woods and many other sustainable features.  A second floor outdoor covered living space offers a stunning view of Linkhorn Bay.  See also Facebook event.

Virginia beach architects

Custom home located in Virginia Beach.

12
Apr
2016

Virginia Beach House Tour

Announcing a house tour at the soon-to-be completed house on Linkhorn Bay in Virginia Beach.  The tour will be postponed date to be determined.  We will meet in the parking lot of the Cavalier Golf and Yacht Club at 1052 Cardinal Road, Virginia Beach.  Limited attendance.  Please RSVP to aewing@hays-ewing.com See more details below.

tour_brochure.pptx

26
Oct
2015

Lewis & Clark Exploratory Center of Virginia: Engaging people is key to a building’s success

We design with the philosophy that engaging people in our buildings is key to a project’s success.  We think a lot about how to create opportunities for discovery, for collaboration, for a conversation with nature… Take for example, The Lewis & Clark Exploratory Center (LCEC).  We designed the roof as an vegetated garden/overlook to the Rivanna River.  This is where a visitor first arrives and the roof signals the building’s larger goals: to connect to the Lewis & Clark story, and to engage the visitor with nature.  The vegetated roof is to be planted with species gathered by the explorers on their journey west.  The overlook, with a replica of a ship in the foreground and the Rivanna in the background, recalls to the visitor that the exploration was carried out by river.  The building also teaches about water, how precious it is, how it is the source of life: the roof water is directed to a riverstone channel that flanks the stairs descending to the exhibit space.  Water is collected in a basin at the entry below and the visitor crosses a bridge to enter the building – again, references to Lewis & Clark’s river journey as well as modern concerns about the environment and the importance of water quality.  The building is designed to achieve LEED Silver, and its many sustainable features are teaching examples for visitors.  Best of all though is how active the center is with community activities.  The building teaches about the Lewis & Clark’s journey, about nature while serving as an ideal setting for the activities organized by LCEC.  It is gratifying to see our goals realized.  IMG_1463IMG_1478

29
Jul
2014

shape in context

Bermann’s Rule (1847) – members of species are larger in colder parts of their range attributed to surface to volume ratio.

Bermann’s Rule (1847) – members of species are larger in colder parts of their range attributed to surface to volume ratio.

The natural world has many examples of adaptation to climate. The northern white-tailed deer has a lower surface area to volume ratio than does its more diminutive southern cousin and radiates less body heat per unit of mass, allowing it to stay warmer in the colder climate.  The southern white-tailed deer has a higher surface are to volume ratio facilitating heat loss through the skin, helping to cool the body.  The former is built to retain heat, the latter to cool.

vtvaThe advent of heating and cooling systems coupled with improvements in the building envelope and cheap energy have led to the homogenization of homebuilding. Compare the floor plan of a developer home in Vermont to one in Arizona. Apart from a little white cladding here and stucco there, the blueprints are the same. I grew up in a 1770’s home in Vermont that was four rooms over four (more volume to surface area). The traditional home in Virginia (where I now reside, apparently I can only live in states that start with “V”) is two over two (more surface area to volume). The former built to heat, the latter to breathe.  Vermont has 6006 heating degree days (measurement that reflects the demand for energy needed to heat a building), Virginia has half that number, 3304.   Vermont has 747 cooling degree days while VA has 1422 (twice as many).  Without air conditioning, modern heating, homes from the 18th century were adapted to conserve or reject heat — a strategy seen in nature and one which, when applied to the building industry, has low first costs. This is a strategy the Developer-Builder can easily adopt. It’s called Regionalism.