Re-Post: The All-Glass Building – Is Energy Efficiency Possible

By Andrea Love, Chapter Board Member

One of our wonderful volunteers wrote extensively about glass facade buildings and the challenge these present to proponents of energy efficiency. Take a look at her recent blog entry at NESEA. Thanks for explaining this for us, Andrea!

 

Glazed towers dominate the skylines of our cities. However, most have been designed with little thought as to the climate in which they are located or the environmental impact they might have. According to the Commercial Building Energy Consumption Survey (CBECS) in 2003, 70 percent of energy use in commercial buildings is from the lighting and HVAC systems. The performance of both of these systems is directly related to the design and performance of the building envelope. Sealed, glazed façades, now so ubiquitous, lead to higher heating and cooling loads as well as glare and thermal comfort challenges.

Despite these challenges, many design teams pursuing sustainability continue to use all-glass façades because of their ability to connect interior and exterior environments. The market continues to demand, and architects to deliver, high glazing percentages for the daylight, views, and marketing potential they provide in green buildings. Such designs are difficult to make energy efficient, but many argue that fully glazed buildings, when designed correctly don't increase a building's energy usage.  

The question remains: is an all-glass building a sustainable building?

Daylight

The principal benefit of glass façades is their ability to allow natural light into living and working spaces. Daylight provides high-quality illumination with less radiation than most artificial light sources, including fluorescents. When coupled with a high-performance glazing system, natural daylighting can reduce the heat load that comes from artificial light fixtures. A lighting control system that responds to changes in daylight can yield a dramatic reduction in the building's lighting energy use.

In addition to the energy benefits from daylighting, studies have found numerous psychological benefits. A 1999 study by the Heschong Mahone Group found that students in classrooms with more natural light scored up to 25 percent higher on standardized tests than other students in the same school district. Studies looking at the effect of natural light on productivity date back to the 1920s, when they were conducted on silk weavers; even then, daylight was shown to increase productivity. Numerous subsequent studies have shown improved performance and increased attention and alertness in occupants of daylit buildings.

Exposure to daylight has also been shown increase sales in retail establishments such as Walmart and Whole Foods. Walmart installed a daylighting system in one of its Kansas stores in the 1990s and had store employees rotate goods for sale under the natural light source; items sold better when under daylight.

Daylight has many benefits, but few studies have investigated how much glazing is needed to achieve good quality natural lighting. Most buildings do not need to be completely glazed to benefit from daylighting. For example, the glazed area below a work surface in an all-glass building has minimal impact on the daylight in a space.

Daylight has many benefits, but few studies have investigated how much glazing is needed to achieve good quality natural lighting. Most buildings do not need to be completely glazed to benefit from daylighting.

The rule of thumb in the industry (recommended by organizations such as Lawrence Berkeley National Laboratory) is that only 30 percent glazing is needed for optimum daylighting performance. Our findings atPayette corroborate this figure. Our computer simulations on the impact of the amount of glazing on daylighting have found in multiple projects that the Useful Daylight Illuminance (UDI) does not increase at all beyond 50 percent glazing. UDI looks at how much light a space receives above a specified target but below the threshold of lighting levels that will cause glare and discomfort. For example, a recent investigation for an east-facing office concluded that 40 percent glazing provided no any more useful daylight than 25 percent.

Energy

A well-designed daylighting strategy can decrease a building's light energy use and associated cooling load. However, as lighting power densities decrease with more efficient lighting technologies like LEDs, lighting represents an ever smaller portion of a building's total energy use. Glazing's biggest impact on building energy consumption comes from its impact on a space's heating and cooling loads. The solar heat gain from the sun increases proportionally with the amount of glass on a façade, which in turn increases the energy needed to cool the building.

A number of strategies exist to mitigate solar radiation, from external sun shading to frits and coatings on the glass. A well-designed shading system can significantly decrease but not block all heat gain, particularly on east- and west- facing façades, where low sun angles are particularly challenging. 

In a cold climate like New England, the increase in heat loss in the winter as a result of high glazing percentages can significantly impact energy use. The current code requirement for maximum U-values for glazing is seven times higher than that of an opaque wall. Even with code-compliant glazing to high-performance triple glazing, the U-value is still three to four times greater than the maximum allowable for an opaque wall assembly. As a result, fully glazed buildings always have a much higher heating load than more moderately glazed buildings.

Double-skin façades have grown in popularity in recent years as a way to improve the energy performance of all-glass buildings. They work by capturing heat between the two glass walls to reduce winter heat loss and ventilating the same cavity in the summer to minimize heat gain. An integrated sun shading system between the two glass walls can further improve performance in the summer. While the double-skin façade can typically decrease a building's energy consumption in relation to a conventional, fully glazed façade, it still does not perform as well as an opaque wall with glazed openings.

Because lighting energy loads are decreasing and HVAC energy loads are increasing as the amount of glazing increases, an energy model is often the best method to determine the optimal amount of glazing.

While there is some variability based on the building type and climate, we have consistently observed buildings with a moderate amount (around 20 to 30 percent) of glazing use less energy than a fully glazed façade or one having little to no glass. 

Comfort

Creating comfortable environments for building occupants in all-glass buildings can be a challenge. Direct solar radiation, particularly in the summer, can create localized hot spots in the building. If the thermostat is not in the sun and is therefore not experiencing the raised temperatures, it will not adjust the HVAC system to make the space comfortable for those in the sun. If the control is in the sun, the HVAC system can overcool occupants that are not directly in the sun, especially in open office spaces. A well-designed solar control strategy, using interior blinds or exterior sun shades, can mitigate this discomfort.

Winter conditions can also pose thermal comfort challenges in all-glass buildings. Because glass does not insulate well, it has a lower interior surface temperature than an opaque wall assembly. This increases the radiant heat transfer that happens between an occupant and the façade, and can make occupants feel cold even at a comfortable air temperature. The colder surface can also create a downdraft along tall vertical pieces of glass. Downdrafts occur as warm interior air hits the cold surface of the glass and falls, creating cold convective currents with temperatures and air speeds that can cause discomfort. 

To combat this discomfort in fully glazed buildings, perimeter radiant heating is often added. Using a high-performance assembly, such as triple glazing, will raise the interior surface temperature, decreasing the radiant heat transfer and reducing the downdraft which can often create a thermally comfortable environment without the need for perimeter radiant heating. However, because comfort is determined by both glazing area and the U-value of the assembly, there is a limit to how low the U-value can be without needing mechanical means to create a comfortable environment. For the Boston climate, we have found that full-height glazing (60 to 70 percent glazed or higher) to be the comfort limit with a good triple-glazed window.

Visual discomfort can also be a challenge to control in fully glazed buildings. While increased glazing increases the amount of daylight in a space, you can have too much of a good thing, resulting in overlit spaces at the perimeter that create glare problems. A well-designed exterior shading system or fritted glass can help mitigate glare, but low sun angles in the morning and evening can still pose a challenge. Interior blinds are the most common glare-control strategy. Unless they are automated, however, they frequently are lowered during a brief period of glare and are not raised again. While this controls glare, it erases all of the benefits of daylighting and exterior views that you can get from glass.

Views

Visual connection to the exterior environment and nature is one of the biggest benefits of all-glass buildings. Views to the external environment have been shown to benefit the health and productivity of occupants because of the biophilic connection between humans and other living systems. The most famous of these is the seminal study by Roger Ulrich in 1981 that found that medical center rooms with views improved patient recovery rates by eight percent. As with the daylight studies, the percentage of glazing needed to achieve quality views is unclear. Some argue that punched windows common in buildings with limited glazing act much like a picture frame, allowing access to views while maintaining the thermal integrity of the building envelope.

Aesthetics

Because large panes of glass weren't commonly available until the mid-twentieth century, fully glazed buildings are associated with modernism. Both designers and building owners demand highly glazed buildings to give the image of transparency and modernity. But in an age where we must think about the environmental impact of the built environment, many argue that it is time to end our collective passion for all-glass buildings. Fully glazed buildings have become so ubiquitous that we as designers should embrace the challenge of creating a new image for what it means to be modern in this age. Design is about embracing constraints to create a new and beautiful building, and working with materials other than glass should be embraced as part of our design challenge. 

Advocacy Update

By Grey Lee

Greetings Green Building Advocates!
 
Here is an update on our key advocacy issues for 2015, Property Assessed Clean Energy Financing (PACE), Net Zero Building Code, and Net Metering.
 
Our PACE stakeholder focus group—made up of around 12 organizations and trade groups, primarily with environmental, labor, and economic development interests—is gaining momentum and working towards strengthening support for this year’s legislation. We are working with Senator Joyce’s office to bring in other co-sponsors up until the bill is brought out of committee. We are also collaborating with the Climate Action Business Group (CABA) to have a public forum around PACE financing and its relationship to resiliency planning.
 
Net Zero
The current version of the Act promoting zero net-energy buildings in the Commonwealth by Senator Eldridge is gaining more co-sponsors, and is targeting a more stringent path to Net Zero Building Codes. The advocacy team is continuing to expand our network of support around this issue.

Net Metering
Our advocacy team is following the progress of the Department of Energy Resources (DOER) Task Force on Net Metering. Among the issues the task force is examining are the potential impacts of a minimum bill for Massachusetts ratepayers and its impact on reaching the statewide goal of 1,600MW of solar. The task force has outlined 5 primary tasks to accomplish which you can see in detail here:consulting team status update and task presentation; the task force also provides a Table of policy options and a draft of the task 1 report

 
 
Mark those calendars now, the next Green Breakfast will be held on Thursday March 19th and we will have presentations to describe each issue, and how you can help build momentum to pass this years legislation!
 
 
 
 
 
 

The Green Engineer Spotlight

By Grey Lee

Cambridge Center Expansion
Biogen Idec

 

When Biogen Idec decided to locate their 204,000 sf expansion in Kendall Square, they also decided to work with an all-star cast of design, construction and real estate professionals. The project was developed by Boston Properties, designed by Elkus Manfredi, and built by Lee Kennedy Co. The Green Engineer helped to ensure the building attained LEED Gold certification for Core + Shell. The new office and lab space is linked to the existing Biogen building by a two-level connector structure, and is also powered by an existing steam plant.

 

The project earned 63 points, reducing indoor water use by 30%, potable water use in irrigation by 50%, achieving a 16% improvement in baseline building performance, using recycled building materials, and specifying FSC-certified wood products. For more details on the energy-saving features of the project check out the LEED scorecard here.

 

  

 

 

Massachusetts ranks fifth in 2014’s Top 10 States for LEED

By Stephen Muzzy, Programs Manager

Massachusetts earned fifth place in our annual Top 10 list.
The results are in! All of the states that make up our Top 10 list have done an extraordinary job promoting LEED and making sustainable solutions a priority.  

View the list »

“The USGBC Massachusetts Chapter is proud to represent the high-achieving professionals of the green building industry who have worked hard to make Massachusetts a leader in the creation of LEED-certified space,” said Grey Lee, executive director USGBC Massachusetts Chapter.
Massachusetts certified 99 projects representing 14,662,950 square feet of real estate, or 2.2 square feet per resident, in 2014.
A sample of notable projects that certified in Massachusetts in 2014 includes:

Unitarian Universalist Association new Headquarters in Boston, LEED Platinum
Massachusetts Institute of Technology’s 130 Brookline Street in Cambridge, LEED Gold
Athol Public Library in Athol, LEED Platinum
Harvard Law School Gannett House in Boston, LEED Gold

Take a second to congratulate yourself, your colleagues, your legislators, and your friends on a job well done! Want to share the good news? Use the hashtag #Top10LEED on Twitter and Facebook.

Boston Properties Spotlight

By Grey Lee

Boston Properties:
LEED Gold, Class A Office Spaces 
 

Boston Properties certified two Class A, LEED Gold office buildings in 2014: 230 CityPoint and Reservoir Place, both along the 128 Corridor in Waltham. 230 CityPoint is part of a larger development which already includes another LEED Gold Certified building, 77 CityPoint. The two 6-story buildings provide over 500,000 sf of multi-tenant Class A office space, including a cafe, fitness center and conference center. 230 CityPoint earned 61 points to achieve its Gold certification, reducing indoor water consumption by 25%, using recycled materials and achieving an 87 Energy Star Performance Rating. The 25-acre CityPoint site features several additional parcels currently under development, 10 CityPoint and 99 Third Avenue Retail. See the LEED Scorecard here.

 

 

 

 

 

 

230 CityPoint
 
77 CityPoint

 

 

10 CityPoint (Under Development)
 
99 Third Avenue Retail (Under Development)

The second LEED Gold building certified by Boston Properties in 2014 is Reservoir Place, a 527,000 sf Class A office building on the northern edge of the Cambridge Reservoir. In addition to being the largest multi-tenant office building on Route 128, Reservoir Place features a cafe, fitness center, several shops and even tennis courts. Reservoir Place was constructed in 1955 and renovated in 1983, and not acquired by Boston Properties until 1998. The decision by Boston Properties to bring the project up to LEED Gold standards for Building Operations + Maintenance, represents their commitment to investing in energy-efficiency for both new and existing construction. See how Boston Properties was able to transform an existing building into a LEED Gold project by checking out the Scorecard here.

 

 

 

Reservoir Place
 
Reservoir Place

 

 

 

Sustainable Landscape Networking Night on Cape Cod

By Adam Prince, ZeroEnergy Design

by Adam Prince, ZeroEnergy Design

 

USGBC MA Cape & Islands Interest Group just enjoyed an evening with two sustainable landscape design presentations and a quick tour of a newly renovated commercial building.
 
Michael Talbot, co-owner of Talbot Ecological Land Care and principal at Environmental Landscape Consultants, LLC, and Seth Wilkinson, President of Wilkinson Ecological Design, each presented a program on ecological and sustainable land development.  Michael provided an overview of sustainable landscape design and management principles, and Seth followed by reviewing case studies of how to incorporate sustainable design by including these principles in the planning and permitting phase of the building process.  Each took questions afterward, as the 20-ish attendees enjoyed a fabulous food spread with refreshments sponored by Cape Associates.
 
The evening ended with a quick tour led by Adam Prince of ZeroEnergy Design together with Seth Wilkinson, as the group investigated the well insulated office building for Wilkinson Ecological Design which recently underwent a full gut renovation. With green architecture and mechanical design by ZeroEnergy Design, and construction by CapeWide Enterprises, the tour highlighted the many green features of the building.
 
PRESENTERS:
Michael Talbot, co-owner of Talbot Ecological Land Care
 
Seth Wilkinson, President of Wilkinson Ecological Design
 
SPONSOR
Cape Associates

AHA Consulting Engineers Spotlight

By Grey Lee

815 Albany Street, Graduate Student Housing

This year AHA Consulting Engineers completed a number of LEED certified projects, including the LEED Gold Certified Graduate Student Housing Project for Boston University. Developed by the Fallon Company, and designed by Beacon Architectural Associates, the 84,000 sf, 9-story project houses over 200 graduate students in 104 2-bedroom suites. Construction was finished in 2012 with a budget of $33 million, or around $390 per sf. This is the first phase in a larger development project on 1.7-acres adjacent to the Boston University Medical Center. The project includes a 12,000 sf park, and over 400,000 sf of development comprised of three buildings and parking facilities.

AHA's role on the project as Mechanical, Electrical and Plumbing engineers significantly enhanced innovation in energy efficiency, and helped the project achieve LEED Gold Certification. The project reduced potential water consumption by 40% through the installation of low-flow fixtures, and by harvesting rainwater for use in a high-efficiency irrigation system for native plantings, which in conjunction with permeable surfaces, helps reduce storm water runoff.
 

 

The building is 18% more energy efficient than required by code, thanks to high-efficiency building envelope, efficient heating and lighting, energy recovery, and regenerative-drive elevators. There are individual thermal controls in every space, including offices and commons space to help save energy when spaces are not in use. The building employs both natural and mechanical ventilation to meet ASHRAE requirements, which improves the indoor air quality while saving energy.

Other programs in the building include a gym, extensive bicycle storage in the basement, laundry, and the Little Sprouts child care and early childhood education center on the ground floor. All of these features combined make a great place for graduate students to live well while saving energy. The project earned a total of 60 points, you can see more details by checking out the LEED scorecard here.

The Delight of the Living Building Challenge

By Grey Lee

This past Saturday, the USGBC MA Chapter convened a tour of the Bechtel Environmental Center at the Smith College Field Station in Whatley, MA.

Student volunteers from Smith hosted us, first greeting us at the end of a long and winding country road, and then to describe how the College uses the facility for a variety of purposes. It was funded by the S.D Bechtel Jr. Foundation, in case you were wondering.

Shawn Hesse, of emersionDESIGN, a new member of our Board of Directors and long-time Chapter volunteer, is also an Ambassador for the International Living Future Institute. He regularly provides trainings and outreach programs for the Living Building Challenge. The BEC (as it is known) is the fifth Living Building ever certified. We are proud that we can visit, right here in Massachusetts, the result of a lot of hard work under the auspices of the Living Building Challenge!

Below is a map of the area.

 
 It was quite picturesque.
 

 

Attending the tour were over 30 people, including Chapter Programs Manager, Steve Muzzy. The place is set up so you have to take a five-minute stroll (longer in the snow) from the parking area to get to the building. Nice gaiters, Steve!

 

 
 
Once inside, you can enjoy the cozy comfort and real beauty of the design – created by Coldham & Hartman Architects. Nice clerestory!
 

Shawn Hesse led the discussion – outlining the basic features of the Living Building Challenge and then going into detail on each of the petals.
 

Here we have the Smith College tour guides explaining how it came to be and how they use the place…including for ski weekend adventures and summer study sessions…
 

 

Here we have the speaking crew: Grey Lee, Emmett Wald, Brice Hereford, Julie Graham, & Shawn Hesse.
 

 I got a chance to plug the Chapter and Brice gave the pitch for the visitors to become part of the West Branch. It was actually interesting how many people – perhaps a dozen – actually came out from the Boston area to see the place. Living Buildings have some real star power!

 

 
So cute!
 

Part of the Living Building Challenge is its petals and one of them is Equity – quite an advanced subject actually, and unfortunate that we have to enshrine it in a reward system like LBC rather than it being a spontaneous manifestation of the built environment. 
 

And here are the requisite solar panels which enable the facility to achieve net zero energy. Now here are things that manifest rather regularly in the built environment. More every day!
 

 
Another petal is Health:

 

We anticipate returning to the BEC for a summer gathering – perhaps a solar-powered sustainable BBQ of some kind? I have a SolSource parabolic concentrator we could use for a giant pot of vegan chili! 

At any rate, thank you to all the presenters, all the parties involved in the creation of this beautiful Living Building, and to all the attendees who made it through the rough roads and deep snow to visit and learn with us. We look forward to promoting the Living Building Challenge throughout Massachusetts and beyond.

See you next time!

Thank you for additional photos from Shawn Hesse, David Bliss and Chris Farley

Reducing Power Plant Emissions

By Grey Lee

EPA Rule 111: Clean Power Plan

In 2013, the EPA proposed a new carbon pollution standards for power plants under section 111 of the Clean Air Act.  The program is designed to regulate and reduce greenhouse gas emissions for new power plants under federal guidance and to address the emissions of existing power plants through a state-based program.  These proposals are designed to cut emissions from the power sector by as much as 30% by 2030, which will help to protect our health and the health of the environment for future generations.  For a comprehensive list of benefits, see the EPA's fact sheet on the Clean Power Plan. This diagram helps to explain the different kinds of greenhouse gas pollution and which sectors are major contributors.
 
 
This map shows the location of the 54 fossil fuel fired power plants in Massachusetts. The data points and background map come from the U.S. Energy Information Administration (EIA); their online mapping system allows users to explore the various sources of energy production and distribution across the United States.
 

In December of 2014, the USGBC submitted recommendations to the EPA supporting their Clean Power Plan, proposing that States be given flexibility in developing their individual compliance strategies.  The USGBC also suggested that existing knowledge around evaluation, measurement and verification used in the LEED system be applied to tracking the reduction in emissions of power plants.

The EPA Clean Power Plan proposes 4 building blocks for states to achieve reduced power plant emissions, 1) power plant efficiency improvements 2) dispatching to cleaner natural gas combined cycle plants 3) renewable energy and 4) energy efficiency.  The fourth building block presents an opportunity for Massachusetts professionals to leverage their leadership and expertise in green building practices to help the Commonwealth achieve these important goals.

 

2014 LEED Certification in Review

By Grey Lee

2014 was a great year for green building and LEED Certification in Massachusetts!  Of the 130 total projects certified in 2014, 19 earned LEED Certified status, 29 earned LEED Silver, 61 earned LEED Gold, and 21 earned LEED Platinum.
 
 
We want to thank all of the project teams for their hard work and commitment to innovation in efficient design, construction and operation. We are looking forward to another impressive year in 2015 and we already have three certifications completed this year, including a LEED Platinum project by our sponsor The Green Engineer.  The following top ten list ranks firms and owners whose project administrators helped certify over 50 LEED projects together in 2014.
  1. The Green Engineer (Sponsor)
  2. Harvard University
  3. AHA Consulting Engineers (Sponsor)
  4. Entegra
  5. Bergmeyer
  6. New Ecology
  7. Urbanica
  8. ADD; CBRE; Chapman Construction; TND; VHB; Wright Builders
  9. Boston Properties (Sponsor); Boston Global; Corgan; GSA; Perkins + Will; TT Arch
  10. AECOM; Architerra; Callison; Goody Clancy; Mount Vernon

 

Look for upcoming blog posts highlighting our sponsors and some of their recent achievements in Green Building.