• Hawai'i Prep Academy Energy Lab

    Kamuela, Hawai'i

Hawaii Preparatory Academy Energy Lab


Conceived as a high school science building dedicated to the study of alternative energy, the new Energy Lab at Hawaii Preparatory Academy functions as a zero-net-energy, fully sustainable building. The project’s fundamental goal is that of educating the next generation of students in the understanding of environmentally conscious, sustainable living systems.

The building’s donor, the founder of a German alternative energy corporation, believes that only through generational education will we truly achieve improved patterns of sustainability. It was his initiative that challenged the design team to develop a green science building, insisting that it be powered principally by alternative means. The design team and Hawaii Prep’s Science Dept. Head have furthered these goals, expanding the mission to include a great number of building systems that employ sun, water and wind. The project targeted, and subsequently achieved, LEED Platinum and Living Building Challenge certification. Completed in January 2010, the Energy Lab today strives as a living laboratory, furthering its educational goals as a functioning example of sustainability.

The Energy Lab was developed in response to the science curriculum it houses. From small project rooms, to a large research center, to a laboratory, spaces were designed to encourage student discovery, exploration and experimentation. The building’s configuration facilitates scientific study both indoors and out, linking interior spaces with the surrounding landscape. Students are surrounded by the systems that they study, and constantly reminded of their methods. Hawaii Prep’s Energy Lab offers a continuous sustainable ‘teaching moment’.

Use the icons below to find out how this project approached each Petal of the Challenge.


© Matthew Millman Photography, courtesy of Flansburgh Architects

Site condition prior to project start:Greyfield

Significant site information:
The Energy Lab was built on land that was previously used as the Hawaii Preparatory Academy campus bio waste (and other materials) dumping area where trees and debris for a prior campus project (faculty housing) were buried.

Name of Habitat Exchange project:Save the Redwoods League
Location of Habitat Exchange project:California
Name of participating Land Trust:Redwood Land Program
Land Trust website: www.savetheredwoods.org/

Biomimicry-related information about species living in Habitat Exchange project area:Trees such as coastal redwoods are teaching people how to develop more sustainable technologies, including how to move water without pumps through cities and fields, generate solar energy without creating toxic manufacturing waste and provide new ideas on optimizing materials for strength.

Related regulatory appeals:NA

Additional Site Petal comments:The building was intentionally located at the windward edge of campus to take full advantage of the abundant trade winds that accelerate down from the hillside above. The site faces due south to picturesque 14,000-foot Mauna Kea volcano. Due southern exposure optimizes solar thermal and photovoltaic panel performance and enables many interior building views directed toward the volcano and valley below. Given the favorable Hawaiian climate and the building’s dramatic hillside setting, direct connections to the outdoors are enhanced via operable glass doors. An entry court is located to the east, a large teaching porch opens directly south, and a wind-sheltered court to the west sponsors an outdoor, covered classroom. The topography of the hillside is reflected in the stepped, terraced arrangement of the building’s internal spaces, where storage tanks, solar panels and other systems have been strategically located to take advantage of this change in elevation.

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Annual Water Use
Harvested onsite:6,593 gal/yr (using local rain data)
Estimated total water use per capita:197.3 gal/yr
Sub-metering data:4,932 gallons used in one year, ranges from 158 to 740 gallons used per month.
Rainwater cistern size:1,800 gal
Collection strategies:Rain
Systems fed:An individual wastewater system provides treatment for domestic wastewater and on-site infiltration. The proposed leaching field infiltration system disperses the treated wastewater over a larger area. This facilitates an additional degree of treatment from soil biota and filtration as the wastewater percolates through deeper soils prior to recharging the ground water below.

Grey water:NA
Systems fed:NA
Black water: NA
Systems fed:NA

Simulated/designed:11,250 gal/yr
Design tools and calculation methods:Benchmarks, local rain data, hand calculations
Related regulatory appeals:The project filed a rain water collection regulatory appeal with the State of Hawaii Department of Health to allow use potable water from rainwater collection .
Additional Water Petal comments:
The energy lab includes a 10,000-gallon water storage tank. Water from this tank is filtered for potable drinking water, as well as for waste systems. Water demand is reduced via low-volume sink and toilet fixtures.

Learn more about the Energy Lab's approach to permitting their water system in this case study.

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© Matthew Millman Photography, courtesy of Flansburgh Architects

Type + size of renewable energy system(s) used:Power for the building is provided by three discrete arrays of photovoltaic panels providing a total of 26.13 kW of PV power. The PV array is a hybrid system with three discrete panel types:

  1. North array: 10.8 kW PV with built-in inverters, 48 volt bus, 3 x 16 x 210 Watt Sanyo panels with built-in enphase inverters
  2. Central array: 12.6 kW PV, standard Sanyo 210 Watt PV panels, feeding 2 x 6 kW SMA inverters (6.3 kW each)
  3. South array: 2.73 kW from 14 Sanyo bifacial 195 Watt PV panels, providing light below and absorbing light in both directions (up and down), feeding into a 3 kW SMA inverter

These systems are grid-tied, using the local power utility grid as a “battery” of sorts. These systems are augmented by a hybrid battery backup system, that is charged via the mains and/or renewable sources in situ, providing uninterrupted power to the monitoring and control systems, computers and data loggers installed in the building. The capacity of this backup system is designed to withstand at least 8 hours of continuous use unattended, with alarms and a phone tree that is activated in case of failure. In addition there is a solar thermal array and an experimental radiant cooling system, consisting of a radiant cooling array and a 25,000 gal insulated storage tank.

Annual Energy Use
19,090 kWh/yr
Annual electricity generated:38,994 kWh
Energy use intensity: 3.23 kWh/sq ft
Simulated/designed:37,461 kWh/yr


  Actual end use breakdown
Lighting:3130 kWh (includes interior 1371 and exterior 1758)
Fans/pumps:No fans usage, pumps are not separately metered, part of the plug loads
Plug loads + equipment:15,960 kWh
Vertical transport:0
Domestic hot water:0

Design tool(s) and calculation method(s):IES Virtual Environment software was used to build a dynamic thermal model. The IES VE software uses APACHE as the computational engine to predict the various energy flows in building during a Typical Meteorological Year (TMY2). The Typical Meteorological Year for Hilo and Honolulu were obtained from the National Renewable Energy Laboratory (NREL) TMY2 tapes. NOTE: this weather file was later modified to more accurately represent the weather at the site. To further study the details of temperature, velocity and pressure distribution, Computational Fluid Dynamic (CFD) was used.

Additional Energy Petal comments:As an alternative to conventional air conditioning, a radiant cooling system was designed. At night water is circulated through thermal roof panels, cooled via lower evening temperatures, then stored in a below-grade tank for use as chilled water for air handling units during warm afternoons. In addition, the building is entirely naturally ventilated. Building automated louvers maintain temperature and relative humidity levels to maintain interior comfort. If necessary, exhaust fans are activated to induce airflow.

There are 480 sensors in the Energy Lab that measure and control everything from energy and water use to the amount of CO2 in each room. Sensors monitor and control artificial lighting and natural air flow. Every sensor provides current readings online to allow for monitoring of energy use in the building and around campus, the goal of which is to maintain a safe, comfortable space while conserving resources.

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Summary of short- and long-term health considerations for design, construction and occupancy phases:
Construction Indoor Air Quality Plan implemented for the duration of the project, low-VOC and zero VOC materials and finishes, separately exhausted toilets and janitor closet rooms, air changes per hour, operable windows in every space, operable window area is 19% of the total floor area, compliant with Title 24 prescribed air change per hour requirements, full building flush-out for 3 weeks prior to occupancy, 24/7 CO2 monitoring during occupancy, green cleaning program.

Additional Health Petal comments:
Polycarbonate skylights, wood sun screens, and interior roller shades all work together to introduce, reflect, and control natural daylight. These components were strategically employed to satisfy foot candle minimums, tackle glare, and enhance views, resulting in a pleasantly lit interior environment. The building is entirely naturally ventilated. Building automated louvers maintain temperature and relative humidity levels to maintain interior comfort. If necessary, exhaust fans are activated to induce airflow.

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© Matthew Millman Photography, courtesy of Flansburgh Architects

Summary of approach to achieving the Materials Petal Imperatives :
Cost-conscious approach led to the selection of sustainable, Living Building Challenge compliant, mass-manufactured products and materials. Distance radius and density threshold limits for red list compliant materials selections were challenging for the project and led to some creative solutions by the team.

Biggest hurdles to achieving the Materials Petal:
The combination of the Red List and Appropriate Sourcing Imperatives, the need to maintain a construction budget, and building code requirements made some items very difficult to source. For example, the project used glue for laminated beams that does not contain urea formaldehyde, but does contain PRF. Fortunately, a Living Building Challenge exemption was issued for these beautiful and very sustainable beams. A Living Building Challenge exemption was also necessary for the project's roof insulation, which was a BioBased 501w foam insulation with water-based agents. Unfortunately contains required flame retardants, which were required by building code. 

The manufacturer of the operable partition needed for the project noted trace amounts of formaldehyde detected during manufacture process, but not in finished product. Unfortunately the second-closest manufacturer was located in the Midwest. In this situation, meeting the radius requirements of both the Appropriate Sourcing Imperative and the Red List proved difficult. In addition, toilet fixtures were very difficult to acquire. The point of manufacture for most large, heavy density, ceramic fixtures is in Mexico. Typically, only very expensive, select product lines are manufactured in the US. American Standard, Toto and others were too far from the West Coast to meet the radius requirement.

Successful Red List Substitutions:

Original Product   Red List Item   Specified Manufacturer +
Product Names
Trex Composite Decking   PVC   FSC certified wood deck
Acoustic Wall Panels   Formaldehyde   Custom designed recycled cotton core with FSC certified wood frames and hemp fabric covering
Exit Lights   Mercury   Bio-luminescent, non-electrical fixtures, "Active Safety" exit lights

Notable regional products specified:
Hawaii possesses precious few native materials. Besides concrete aggregate for foundation walls and precast counter tops, perhaps the most notable regional product is the functional and symbolic, exterior Ohia Wood Column (at outdoor classroom). This salvaged wood column also contributes to the 'Beauty' petal.

Notable manufacturers who made "Proprietary Claims" when asked about product contents:

  • Armstrong, for the point of manufacture location of ceiling tiles, a proprietary secret apparently.
  • American Olean / Dal Tile for manufacture location of bathroom ceramic wall tile (Mexico). We ended up specifying a denser, and far more expensive tile manufactured in nearby California. We were able to do this by eliminating the floor tile scope in the bathrooms and leaving as exposed concrete flooring.

Sources for wood:certified by Forest Stewardship Council (FSC)

Notable manufacturers of FSC certified wood products:

Product   Manufacturer   Manufacturer Location
Plywood, maple for cabinets   Roseburg Forest Products   Roseburg, OR
Douglas Fir framing lumber, 2x6 decking material   Western Timber Products   Coeur d'alene, ID
T&G lumber   Lignum Forest Products   Shelton, WA
Western Red Cedar lumber   Olympic Industries   Chiliwack, BC, Canada
Maple and Poplar lumber   Specialty Forest Products   Algona, WA
Maple doors   Pacific Wood Laminates   Brookings, OR
Glulams   Calvert Glulams   Richmond, WA

Name of organizations that assisted with timber harvest and lumber seasoning process:
HPM Wood Protection, Hilo, Hawaii (lumber treatment)
Permapost Products, Hillsboro, Oregon (glulam treatment)

Brokers that assisted in sourcing salvaged materials:
Awapuhi Farms & Mill (Ohia Post)
Jay Warner
Mt. View, HI
(808) 968-7074,

Embodied carbon footprint (TCO2e): 202
Name of Carbon Offset project: Bonneville Environmental Foundation
Location of Carbon Offset project: Carbon offsets were expected to be produced from a variety of locations, including wind farms in North and South Dakota, Texas and Washington, as well as solar projects in California.
Name of Carbon Offset provider: Bonneville Environmental Foundation
Carbon Offset provider website: b-e-f.org

Additional Material Petal comments:
A remote location exception was applied to this project.

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Please note that this project was certified under Living Building Challenge 1.3. The Equity Petal was not developed until Living Building Challenge 2.0.

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© Matthew Millman Photography, courtesy of Flansburgh Architects

Project website: www.hpa.edu/academics/energy-lab

Tour information: The Energy Lab hosted a large Community Open House on April 17, 2010 that had been previously publicly announced and has hosted several smaller tours since. For more information about the Energy Lab, or to schedule a tour, call 808-881-4266 (e-mail: elabassistant@hpa.edu).

Useful strategies, tools and references: A user-friendly and interactive interface for the monitoring system allows young students to understand the relationship between climate, energy, thermal comfort and how a responsive building design adapts to different conditions.

Lessons Learned: We were unable to source or reference any useful benchmarks for low-water and low-energy buildings out there which resulted in our systems being slightly over-sized. Since this building is part of a larger campus this was not a big issue for energy overproduction but flexibility should be built into the design since operational strategy is such a big part of how the building will perform and that is difficult to predict.

Additional Beauty Petal comments:Over 90 percent of the students like their new Energy Lab building, think it is beautiful, like having classes there and feel inspired by it!

The following description of the approach to meeting the Beauty Petal discusses three aspects of inspiration: a sense of place, a sense of responsibility and a sense of community:

In Hawaii, there is a word called 'ike ("ee-kay) which means "sense of place". We chose the location of for the Hawaii Preparatory Academy Energy Lab to resonate with its surroundings: south facing for solar energy, exposed to strong trade-winds for wind power and passive ventilation, adjacent to a sustainable agriculture restoration project, and the only disturbed site on the campus, preserving the natural beauty of the land. These alone would make the project fit into its sense of place, but further, we are situated on the grounds where centuries ago first peoples supported whole communities sustainably. We live on an island that is at once remote, yet gifted with a large enough land mass to demonstrate sustainable agriculture, with ample renewable energy and water sources to demonstrate sustainable living, on a site where ancients Hawaiians did so for centuries. It is our hope that this building, on this island, thousands of miles from any large resources can serve as a metaphor for the globe: a finite resource with sustainable resources, that if used wisely can carry us into the future, while enriching people's lives with the inspiration of the building design.

Our motto in the building is "thinking about forever", which suits our mission, our sense of place, and what sort of buildings we can build and operate to conserve resources and serve as a prototype for buildings in the future. We hope to inspire resonance with the sense of place, with the sense of continuity, and with a vision for the future. Our building has elements of traditional tropical huts, meshed with transparent technology that enables occupants to feel part of the environment, rather than insulated from it. Open views, passive ventilation and ample passive lighting enhance the experience for occupants, while connecting them with the beauty of this tropical island. Conservation is a meta-message of the building, leading students to increased awareness of the potential for conservation in the zero energy, zero water and zero waste facility. By changing the ethos of consumption among our students, we hope to create change agents, able to redirect the wasteful practices of our present society to more sustainable, aware lives. 

This leads to another Hawaiian word: Kuleana ("cool-ee-ahna") which translates to responsibility or territory, but which can mean much more: sense of connectedness to the place, history and the future. In a sense, ancient societies lived with both their past and their future acknowledged in every practice. Our energy lab engenders that sense, with the connections to the land (the ancient Hawaiian field system is visible through open windows on all sides), a connection to history (these spaces were once the breadbasket for a thriving society) and connection to the future in our vision for wise use of resources and responsible living. In a sense, these two concepts join at the energy lab to create a comfortable space the gently suggests by example and inspiration a new way to live, within the bounds of renewable resources, as stewards of the resources we are given.

A third aspect of the lab is the anti-classroom approach that educators see right away when they enter. "Where do I line up the kids?" they ask. The energy lab is created to foster team learning, collaboration and discussion, while mimicking the creative process: the building flows naturally from creative/collaborative zones to an open research hall, then to a fully equipped hands-on workshop with access to outside meeting spaces throughout. The sense students have is that they may find their place, whatever that may be, and create their own experience in the process. Televisions for presentations in the main hall are arranged in the center, from the ceiling, where viewers face each other, instead of watching the back of the speaker. It is through such subtle changes that students feel empowered to learn in the new ways, and teachers to teach in new ways, unencumbered by the structure of industrial age educational paradigms. 

This collaboration is extended beyond the reach of the building by video conferencing facilities in every room, so that students can work and collaborate with others anywhere in the world, in any phase of their explorations at the lab. This is in keeping with our missions: education, outreach and research. It is not uncommon to find Kindergarten students working next to graduate students from Stanford - truly a one room schoolhouse in a modern, inspiring setting. 

This brings forth the last Hawaiian phrase: Ohana, ("Oh-hahna"), which means family or community. Our students feel a sense of excitement that they are the ones who will create change, will be the change agents for the future, and who see this building as an inspiration to do more, to be the change they seek in the world. They are like explorers in this world: first of their kind, and destined to create change. Much like the canoe voyagers who settled here, they will bring with them what has worked in the past, open to creating new solutions for the future.

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Relevant details about project use: The Hawaii Preparatory Academy's Energy Lab  consists of 5,000 nsf of science classroom space for a curriculum focused on the study, development, construction and testing of renewable energy technologies. The total square footage is of the facility is 9,000 sf. The stated goals of the project were to meet the Living Building Challenge and achieve LEED Platinum.

Project costs (land excluded):$8,306,199
Soft costs:$1,314,569
Hard costs:$6,991,630

Creative financing opportunities:

  • $2 million from Hawaii Preparatory Academy funds
  • $6.334 million from a single donor

Design Process: The integrated design process included the owner, the owner’s project manager, an energy/sustainability consultant, structural engineer, and MEP engineer. Several week-long working sessions conducted on site and attended by the entire project team allowed design ideas to be studied from multiple perspectives, fostered systems integration and enhanced communication. Flansburgh Architects' role was to establish a clear project idea, engage project team members in the design process, and inspire them to develop creative solutions that supported the design vision. For example, physical models of the proposed building and dynamic energy models prepared by an energy/sustainability consultant were used to develop and refine the shape of the building. The structural system was developed to be the architectural expression. The owner’s project manager advised on local construction systems and project costs.

Special constraints:The project is located on one of the sunniest and windiest places in the country. The site is relatively remote with an 18 percent slope. Dynamic thermal modeling was used to study the wind pressures around the building. In the end, the design was modified to ensure 12 air changes per hour.

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All project photos by Matthew Millman Photography, courtesy of Flansburgh Architects