Windows for Passive Solar Homes

window

 

Although much has been written about passive solar design, and some mention is made of selecting glazings appropriate to the building aspect, sourcing windows with glazing both optimized for passive solar buildings, and reasonably priced can be less than straight forward.  Window manufacturers in the U.S. tout the insulative properties of their windows (their u-value) to reduce heating loads, and how well they exclude solar heat (low Solar Heat Gain Coefficient, or SHGC) to reduce cooling loads.  Both of these qualities are achieved with a combination of double glazing, and low-e coatings. However, by using glazings optimized for low u-value and high SHGC, south facing windows can contribute significantly to the winter heating of a house. Most factory wood and clad-wood window offerings in the U.S. only include low-e glazings optimized to exclude solar heat. This is presumably because the vast majority of homes are designed without regard for the sun, a single window brand may be distributed across very diverse climate zones, and the prescriptive energy codes dictate low u and SHGC values, but give no credit for passive heating. It is easier to offer a handful of glazings which will work reasonably well at meeting code, at the lowest cost, in both heating and cooling dominated locations.

 

On one of our first passive solar designs to be built we clearly told the client (and builder) that they needed to chose glazing appropriate for the window’s aspect. She chose one of the premier residential window brands for her new guest house and art studio, located in the high desert of the southern Utah. During the first winter the building was occupied she contacted me wondering why it required more supplemental heating than I had predicted. Upon investigation, I realized the window’s high performance glazing was as described above, and excelled at heat exclusion. Since then we have designed a number of homes in that neighborhood, all of which successfully use tuned glazing, and which perform as designed.

 

Fortunately, there are a few windows available well suited to passive solar homes, and hopefully more in the future. All these companies offer glazings suitable for non-south windows as well. Loewen offers an array of double and triple glazings, including triple clear which meets code minimum for u-value in most climate zones, and offers a high solar heat gain coefficient (SHGC). Eagle windows are available (although this isn’t mentioned in their literature) with Alpen’s heat mirror glazings, which have suspended films tuned for different purposes. Experience with ordering this seems to vary between dealers. Cardinal recently introduced a low-e film optimized for solar heat gain, Low-E 179. Semco offers it as an option; ask and encourage other brands who use Cardinal glazing to do so. Serious Materials is a relative newcomer whose offerings look very promising, addressing glazing tuning as well as overall window efficiency. A number of high performance Canadian fiberglass windows are available as well, although at a significant premium.

 

A high SHGC glazing can let in over twice as much heating energy as a glazing optimized for cooling, with only a small reduction in insulative performance. After designing a passive solar home with a large collector area of south facing windows, appropriately shaded in the summer, take the time to spec appropriate windows, and educate the client and contractor about the importance of the glazing choice.

 

Kalen Jones is a founder and principal at With Gaia Design.  With Gaia provides sustainable architecture and landscape architecture design, consulting, and education services.  Their focus is passive solar homes, civic and commercial site design.

 

Trivett Distribution Center

Our friend at Baskervill in Richmond, Virginia offered us some insights into how green design strategies can be applied to a large commercial distribution facility to yield tangible savings. They were able to achieve 5-year pay-back for all of the green design investment incorporated, while making it possible for the client to realize an additional tax rebate to further justify the up-front investments. This case study is just another example of how all architecture should be green architecture.

 trivett

TAX INCENTIVES: 

The Trivett Distribution Center is a 300,000 square foot warehouse that Baskervill designed to capture all of the tax credits available through the Energy Policy Act of 2005. The distribution center achieved 57 percent more energy efficiency than the baseline energy standards.

The Energy Policy Act of 2005 (EPAct 2005) was enacted to provide a new federal tax deduction for expenses incurred for new and renovated energy-efficient commercial buildings. The maximum deduction for the whole building is equal to $1.80 per square foot, with partial deductions available. Applicants must acquire the blueprint for energy tax incentives from their qualified tax professional. The EPAct 2005 includes incentives for building owners as well as the lessee.

The improvements must reduce the energy and power operational costs by a minimum of 16 2/3 percent over the baseline energy standard as outlined in the ASHRAE 90.1-2001 requirements, the code minimum at the time the act was established. A qualified engineer is required to prepare an energy model using certified software as approved by te Department of Energy.

The maximum deduction is reached by achieving 50 percent over the baseline energy standard, which allows full credit of $0.60 per square foot for each of the three separate building systems:

  • Interior lighting system
  • Heating, cooling, ventilation, and hot water systems
  • Building envelope

Some of the strategies employed include:

  • Automatic lighting controls, occupant sensors, photocells, timeclocks
  • Daylighting
  • Semi-conditioned space – heating and air conditioning with reduced thermal comfort standards
  • Improved fan efficiency, reductions in static pressure

Currently EPAct 2005 tax deductions have been extended until 2013. The calculated payback for Trivett is under five years without factoring in the tax deduction. Due to the overwhelming success of this project, our industrial team attempts to achieve some level of EPAct benchmarks in all of our distribution centers as a standard of practice. Having the incentives in place gives our clients the financial benefits for having done so.

DESIGN STRATEGIES: 

Water-proof Membrane (No vapor barriers required): Continuous on all six sides of building either above or below continuous insulation.

Lighting: Use only dimmable fluorescent (T-5) with 10% dimming electronic ballasts controlled by sensors to use available day light.  Use recommended minimum IESNA foot candle levels for the specific visual task.  Automatic occupancy sensors to turn off lighting when occupant leaves a space, and solar sensing blinds to prevent direct sun into the occupied space.

Glass: Exceed Energy Code minimums for performance.  All glass on North & South exposures with South facing glass using external sun shades.  No glass on East or West exposures.

Building Automation Systems: Controlling occupied/unoccupied times of day to optimize lighting, temperatures, security, fire detection and alarm systems.

Insulation: Exceed Energy Code minimums with continuous board insulation type (foam, rigid or fiberglass) for all six sides of building (foam only below lowest floor slab).

Energy Model – Computer software used to calculate energy, power consumption and costs must be approved by the Department of Energy

Heat Recovery Device – Building exhaust air used to pre-heat incoming ventilation air-Total Energy Wheel is best.

Smaller HVAC Loads – Smaller units = less weight on building = smaller footings and structural elements 

BEEP FACTS:

 57% energy use reduction

65% less energy for lighting

25% less energy for air intake

50% high efficacy in mechanical system fans

14% higher mechanical system combustion efficiency

50% higher efficient windows

47% less solar heat gain

16X more efficient warehouse roll-up doors

13X more efficient partitions separating offices and warehouse space

4.7X better insulation value in building envelope

3.3X better insulation value in the office envelope

 

Baskervill Environmental and Energy Practices (BEEP) is an internal resource aimed at educating clients on design that will benefit the environment, as well as maximizing the financial incentives available. Baskervill boasts 26 BEEP team members, over 20 LEED APs, and has currently completed eight LEED certified projects with two more underway.

Lean, Mean Home Heating Machine Wins New Fans with Clean, Efficient Wood Heat

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It is an old world answer for modern heating concerns.  Masonry heaters, also known as Finnish fireplaces, have been used for centuries in Europe and now are gaining notice here as a heating alternative.  Faced with rising prices for fossil fuel, and at the same time environmental restrictions on charming, but smoke-spewing wood-burning fireplaces, homeowners coast to coast are experiencing the unrivalled efficiency and clean burning technology of masonry heaters. 

 

According to the Hearth, Patio & Barbecue Association, the leading international trade association for hearth products, shipments of wood burning appliances, which includes masonry heaters, increased 54% in the first half of 2008, compared with the same period the year before.  Leading the charge for a change to masonry heating is Finnish based Tulikivi.  The company has adapted a centuries old hand-built home heating method to modern production techniques.  Today, Tulikivi (too-lee-kee-vee) manufactures and exports fireplaces that operate at up to 88% efficiency. 

 

While a masonry heater may look like a fireplace, it works differently.  It stores a large amount of heat from a rapidly-burning fire within its masonry mass and slowly releases that heat into the home throughout the day – for as long as 18 to 24 hours after the fire is out.  A Tulikivi’s thermal mass is made of soapstone, an exceptionally heat-retentive natural material, of which Finland is blessed with deep deposits.  A Tulikivi’s fire burns hot inside its closed hearth, converting more of the wood into fuel, meaning less wood is needed to produce the same amount of heat as a traditional fireplace or other wood-burning device.  Just two or three loads of wood – about two baskets full – burned over two hours time are sufficient to generate long-term heat for as much as 1,400 square feet.  The near complete combustion of the wood also means less smoke and ash is produced, too.

 

The EPA recognizes masonry heaters as inherently clean burning, but it does not require them to be certified.  Some state and local governments with localized emissions regulations do require testing of masonry heaters in order to be approved for installation.  Tulikivis are approved nearly everywhere in North America, including three of the most difficult areas for wood-burning appliances to gain approval – Colorado, Washington and San Luis Obispo County in California.

 

In addition to the cost savings of heating a home with wood and the benefits of using a local, renewable resource, masonry heaters are also highly valued for the comfort they provide.  Masonry heaters, like a Tulikivi, combine the ambiance of a crackling fire with a safe and healthy form of heat, emitting only soft, radiant heat – universally considered to be the healthiest form of heating.  What strikes most people as a key difference is that no matter where one is in the room, there is warmth, not just next to the fire, as is the case with traditional wood-burning fireplaces.

 

While masonry heaters will never altogether replace conventional heating, a Tulikivi does an incredible job of heating a home.  “Customers specifically select Tulikivis for their exceptional radiant heating capabilities,” says Ron Pihl of WarmStone Fireplaces & Designs, a long-time Tulikivi distributor in Livingston, Montana.  “But, in the long run, they’re guaranteed unmatched efficiency, ease and comfort.  They also get a striking centerpiece for their home.”

 

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Tulikivi fireplaces and bakeovens are available through a network of dealers in the US and Canada.  For more information and a distributor listing, visit the website at www.tulikivi.com or call 800.THEFIRE.

 

For more information on Tulikivi, hi-res images or an interview with an energy-efficient heating expert, please contact Shannon Burton at French/West/Vaughan, 212.213.8562 x 309 or sburton@fwv-us.com.

 

The Envelope, Please – Cost Effective Energy Savings in Buildings

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First and foremost, green building needs to be about energy savings.   The Architecture 2030 challenge provides milestones for the reduction in energy use in new buildings and retrofit projects with the goal of zero energy buildings by the year 2030 – www.architecture2030.com.   The explosion of green building as a concept confronts reality in this challenge.  How will we actually build and retrofit buildings that produce as much energy as they consume?  The Architecture 2030 Challenge is the architecture community’s declaration of energy independence.  We do not have time to waste and civilization’s very existence may lie in the balance.  Sustainability is a real and pressing issue to you and your children. 

 

The Architecture 2030 Challenge energy savings goal is a 60% reduction in energy use for the year 2010.  That means that buildings you are designing now, or have already designed and are still yet to be built, are supposed to be 60% more efficient than a “code built” structure.  My assertion is that if you are going to say you are committed to green architecture, meeting the goals of the Architecture 2030 challenge should be priority number one.

 

How do we meet these goals without drastically increasing building costs?  Green building is integrated design.  Planning for energy efficiency from the ground up must be the cornerstone of green architecture for new buildings and major retrofits.  Starting with passive solar design, the integrated design of a house or building should prioritize building enclosure technology (thermal envelope), utilize energy modeling, and incorporate HVAC engineering.  Spending time and effort during design to implement energy saving measures creates value; i.e. dramatic results without extra costs.  If you are not energy modeling, you will probably not reach the project’s full potential.

 

I have chosen to focus professionally on thermal envelope technology.  The building enclosure has to be a major priority of your integrated design.  Solar panels and bamboo flooring are getting a lot of attention in the green building world, but reduction of energy loading is the bedrock upon which zero energy buildings will be built.   Give me the thermal envelope…..please.

 

Eric Miller, LEED A.P., assists architects, general contractors and developers in the creation of energy efficient buildings.  As Business Development Director-Western Region for kama Direct, Eric specializes in thermal envelope technology and building enclosure science.

 

 

 

Advances in Living Architecture

 

Roof detail at California Academy of Sciences

Roof detail at California Academy of Sciences

It has become increasingly clear that the design and building of living roofs is making a transition from early adoption to mainstream application. Driven by environmental policy, economic necessity, and social responsibility there is increasing emphasis on a “living systems” approach to building and vegetation design. The designs integrate and complement mechanical and plumbing operations.  The operation of the built environment provides great opportunity for owners and occupants to apply green walls, living roofs, and water conservation strategies that enhance carbon sequestration, energy efficiency, water conservation, waste reuse, habitat renewal, and create a place of “well being”. I have been honored to work with creative designers, architects, and owners on brilliant projects that exemplify sustainable design, architectural ingenuity, community focus, and economic return. This piece highlights recent works, presenting current trends and future opportunity.  

So far real estate developers and institutional investors are implementing living systems because the economic rationale for the development of sustainable buildings has advanced beyond anecdotal evidence. The U.S. Green Building Council (USGBC), a private non-profit organization, has developed the LEED (“Leadership in Energy and Environmental Design”) green building rating system to encourage the “adoption of sustainable green building and development practices.” LEED requires the inclusion of living systems to qualify for certain green building performance objectives relative to site impacts, wildlife habitat, storm water efficiency, and innovation. LEED has been the driver for many Living System projects in San Francisco and elsewhere in the Country.

 

CALIFORNIA ACADEMY OF SCIENCES 

In the heart of one of the country’s largest urban parks, the California Academy of Sciences is a pioneering LEED® Platinum Green Museum in San Francisco’s Golden Gate Park. Rana Creek Living Architecture worked with Renzo Piano Building Workshop, Chong and Partners Architecture, SWA Group, ARUP Engineering, and the Academy to create a living roof that covers 160,000 square feet of roof with four steeply sloped domes replicating the surrounding rolling hills.

 

The roof is planted with over 50 plant species native to San Francisco. The three-year research period during which Rana Creek Living Architecture designed, built and monitored a series of living roof mock-ups, informed this diverse assemblage of indigenous plants, as well as the soil retention and drainage techniques ultimately chosen for the project. The California Academy of Sciences is unique amongst natural history museums in its dedication to combining research and education under one roof.

California Academy of Sciences
California Academy of Sciences

WEST ELM

In the heart of the East Bay, Rana Creek Living Architecture worked with McCall Design Group on a living system for this high-end urban retail space. Within the building design, ecological considerations were incorporated to enhance urban habitat, reduce, capture and treat stormwater on site, and improve air quality.

 

Through a diverse drought resistant plant assemblage, consisting of California native plants and sweet smelling cultivators, the building was brought to life through a combination of a living roof, stormwater planters, and a vertical Green Screen™ that will eventually cover the entire north, south and east walls. The 6,000 sq ft living roof reflects a native California landscape and provides shelter and valuable food sources for birds, bees and butterflies. In addition, the 5,300 sq ft of groundplane landscaping captures and treats stormwater as required by Emeryville’s stringent stormwater requirements. Rana Creek is thrilled to have contributed to this brownfield development and look forward to the day when all urban infill requires living systems to mitigate the impacts of the built environment.

westelm

 

Paul Kephart is the Executive Director of Rana Creek and Technical Consultant for Living Architecture.  Founded in 1997 under the guiding principles of ecology, Rana Creek is a premier design and build firm offering an extensive portfolio of services in land-use planning, sustainable design, ecological consultation and habitat restoration.  Our nursery provides quality plant material for the wholesale trade specializing in contract grow services.

 

Located on a 14,000-acre active ranch in the upper Carmel Valley watershed, Rana Creek’s goal is to replicate nature’s cycles, structure, function and diversity with each stage of project development.  From compliance and permitting to project implementation, Rana Creek offers over 60 years combined experience in environmental planing and design.  Our client list is comprised of world-renowned architects, developers, non-profits, land-use planners, government agencies, and community associations.  Rana Creek’s team of professional biologists, ecologists, designers, contractors and horticultural specialists are well versed in the rapidly growing commerce of sustainable development.

  

Rammed Earth

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Rammed earth has been a part of the alternative materials scene in Northern California since the mid 1970’s, when we first broke through the building permit barrier. Initially our goal was to develop a resource-efficient construction system that would be affordable and widely adopted by the building industry.  We began with a strong commitment to construction simplicity and to the use of site materials. 

As market confidence and client appreciation increased, we continued to improve the technology to meet the demands for a crisp, complex and highly refined product.  Rammed earth’s reputation as an organic, rustic, inexpensive solution for the owner builder morphed into the perfect expression of artistic whimsy for those who could afford any structural system but preferred the visual power of a thick monolithic wall. Thirty years ago “rammed earth” was unknown in California building terminology.  Today it’s on the drafting boards of some of the world’s leading architects.

img_77341Now that rammed earth has grown into the ultimate demonstration of client commitment to green building, we need to step back and consider what might have been lost along its road to recognition.  Maintaining the connection to resource efficiency remains our primary goal, but as projects involve more complex wall systems with tighter specifications, formulations become more dependent on the uniform soil gradations of imported quarry products and stabilization ratios rise in response to engineering demands. 

The upside is that today’s rammed earth walls are immaculate, as well as being safe, quiet and comfortable. The downside is too many eighteen-wheelers on the road burning diesel and too much imported cement from China.  Our carbon footprint increases in proportion to the demand for art walls rather than simple structure. The fact is, a hand made wall with its human imperfections is much “greener” than the perfectly plumb, sharp edged, stratified art walls that are currently in demand. 

The challenge now is to re-focus on our original vision:  can we return to site materials, reduce cement content, simplify formwork and still produce a beautiful, affordable, and supremely sustainable wall system?  It is imperative that we try – for the sake of future builders.

 

David Easton is a graduate of Stanford Engineering’s Product Design Department in 1970; founder of Rammed Earth Works, California’s oldest structural earth wall company; author of The Rammed Earth House; and developer of mechanical systems, soil mix designs, quality control procedures, and seismic strategies specific to building with site resources in earthquake regions.  His project portfolio ranges from low-cost solutions for construction in developing countries to high-end commercial and residential projects in the United States.