Category: passive solar

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.

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

01
Feb
2016

Creating layers of value – What’s good for environment is good for business.

We consider a project unsatisfactory if it’s just beautiful.  We consider a project unsatisfactory if it’s only green — or only functional.  We consider a project falls short if it’s not a good fit for it’s natural setting or urban context.  We seek to create layers of value.  Case in point:  We were asked by Norfolk region based Haynes Furniture to do a facelift on their exterior facade.  Our solution – create a facade that is beautiful but also shades the entrance glazing from unwanted heat gain.  Beautiful and functional.  We wanted to transform the parking lot to one that was full of trees and native plants that filter stormwater before it reaches the endangered Chesapeake Bay.  Beautiful, native to place and green.

We believe by adding layers of value our clients get more for their investment.  Good for the environment, good for business.green architect Norfolk

 

16
Sep
2015

Sustainable design requires creative solutions

A sustainable architect needs to solve for more than would the typical designer.  I liken our process to solving the Rubic’s cube – where all the goals, challenges and givens must be in alignment.  The typical architect might be solving for the nine squares/side cube, we are solving for the 16 square/side Rubic.  Take for instance HEDS-designed RiversEdge House: Good urban design suggested house be sited in alignment with street grid.  Classic #PassiveSolar approach would rotate the primary windows toward south and shade with deep overhangs.  But the street grid wasn’t on a north-south axis.  To solve for both passive solar and urban siting, we angled the front wall toward south while maintaining the overall orientation to that of the street.

This project was designed as part of the RiversEdge community and speculative – we were the developers.  We know first-hand that passive solar takes advantage of free energy from the sun at no additional cost to the builder – a win-win solution.  RiversEdge5-heds

27
Feb
2015

adaptation

Lichen grows on the sunny side of the bark of a tree, capitalizing on the warm of the environment. I’m fascinated by the compass termite amitermes meridionalis, native to northern Australia, that builds its nest like a sundial.  The long axis of a nest (which look like a tombstone) runs north to south to minimize exposure to intense mid-day rays.  The south face of the nest is made of a higher thermal mass material – cob, the north face made with straw bale.  Its air conditioning system involves small capillaries as intake and a large central chimney as exhaust, a wonderful example of thermoregulation. 

With 3.8 billion years of R&D, nature proliferates in well-adapted solutions — solutions solved in context and the context is EARTH.  Learning from nature, taking nature’s advice, is the premise for the book, Biomimicry: Innovation Inspired by Nature, authored by Janine Benyus.

05
Mar
2014

engaging the developer

The developer-builder operates under a series of environmental pressures the most important of which is to sell homes while making a profit.  The Developer-Builders consider first costs, first because profit equals marketability less first costs.  Lifecycle benefits have no power over a builder unless those costs can be justified in sales.  Not surprisingly, strategies such as solar aquatics systems, solar panels, geothermal, etc., have no attraction to the Developer-Builder because the long-term costs savings are realized by the Owner.  So where is the magic line between additional up-front costs and increased marketability?  Robert Hauser of Stonehaus Development in Charlottesville, Virginia thinks an increase in costs of 3-5% is an acceptable risk if his company can successfully brand its houses as energy-efficient.

That leads us to consider adaptive options that are within the Developer-Builder risk-tolerant zone.  So the question is, how can we achieve carbon neutrality by 2030 in a cost-effective way?  We must do so optimizing passive strategies: community, massing, envelope design, and passive solar – all strategies with lower first costs. This is what it will take to transform a profit-driven industry.