False Equivalencies and False Choices

Getting this out of the way first, lest anyone accuse this article of being in the denial camp: Anthropogenic global warming is almost certainly real and will very likely have significant long-term societal, economic, and ecological consequences.  Studying the processes that contribute to AGW, predicting the effects with a high degree of certainty, and finding technological solutions to reduce climate change’s impact should be a high priority of the world’s governments at all levels, as should incentivizing reducing carbon output from all industrial and business sectors.

However, some industries are more ready than others to make impactful changes, by dint of embedded scientific expertise and economic feasibility. The energy sector has low- (and zero) carbon options, for example, and the transportation industry is developing feasible technologies for reducing emissions as well.  The building sector, for all of architects’ good intentions, is still a significant contributor of carbon emissions and architects, by dint of their lack of rigorous scientific and technical training, do not have the necessary expertise to contribute meaningful innovation.

In his recent column in Architect magazine, AIA President Carl Elefante writes that the newest design imperative is reducing and eventually eliminating carbon output from buildings.  “A zero net carbon building sector is the architectural design imperative of our time,” he argues.  In his article, he makes a number problematic arguments.

First, Elefante invokes the changes made to make buildings more fire- and earthquake-resistant: “In 1871, the need for fire-safe buildings rose from the ashes of the Great Chicago Fire. In 1906, from the rubble of San Francisco came understanding that earthquake risk is a design imperative.”  Elefante acknowledges that fires and earthquakes are singular catastrophic events that cause immediate death and destruction; specific deadly events shocked the public into demanding safety reforms that were rapidly baked into building codes.  This is still a false equivalency.  Climate change is acknowledged by the code writers and the International Energy Conservation Code, and requires incrementally improved energy efficiency in envelope design, mechanical and lighting systems.  But since neither architects nor anyone else really knows how to make a building fully zero-carbon, let alone do it for a reasonable cost, there’s no true mandate for architects to follow.

Elefante blunders again by claiming that “in the decade leading up to Paris, the U.S. building sector grew by 20 billion square feet, yet overall energy consumption remained flat.”  This would be quite an accomplishment if true, but it is not.  In fact, from 1999 to 2012 (dates for which data is actually available) commercial building area grew by 20 billion square feet and site energy use grew by 21%.  The positive news from this is that building area grew faster than energy use, but energy use was not “flat.”  We haven’t made as much progress as Elefante or anyone else would wish for.

chart

Chart made for the author by John Scofield, Ph.D., based on his research

Net-zero carbon buildings may be feasible in the future, but saying that it’s the design imperative of our time requires making dishonest claims for what can be achieved today.  Making dishonest claims about what you can accomplish is terrible professional ethics, and for the leading association of architects to advocate that architects act dishonestly is frankly baffling.

Architects and the rest of the design community need to understand more thoroughly how energy use in buildings responds to design decisions, and where the trade-offs are.  For example, if you make a building envelope more air-tight and highly insulated, you likely need to spend more energy bringing in and tempering the fresh air people need to breathe.

There are strategies to deal with these types of problems, but the solutions need more time and more dedicated scientists, engineers, and climate-friendly policy before they’re ready to be incorporated into real-world projects.  Unless owners are expressly consenting to be guinea pigs (while knowing that results are not in any way guaranteed), architects should not be advocating that owners risk their money on unproven strategies.

 

Are Materials Mindful?

Global climate is changing and humans’ burning fossil fuels is a significant contributor to the change.  We burn fossil fuels which adds carbon dioxide to the atmosphere; the additional CO2 increases our atmosphere’s ability to trap heat from the sun.  Both the construction and operation of buildings are huge consumers of fossil fuels and contributors of atmospheric CO2.  The construction industry has recognized its responsibility to the climate by developing methods to construct buildings in a manner that is less environmentally impactful and also to make our buildings consume less fossil fuels.  

There is some encouraging progress; the US Department of Energy recently published its 2012 Commercial Buildings Energy Consumption Survey: Energy Usage Summary which indicates that the rate of increase in energy use is slower than the rate of increase in total building square footage.  It’s a step in the right direction, but what we really need is to decrease how much energy we use and how much CO2 we release.  Architects are in a tough spot in light of this fact, and are under significant pressure individually and as a profession to reduce their projects’ climate impact.  Numerous organizations and initiatives, such as USGBC (LEED), Green Globes, Living Building Challenge, and AIA 2030 have been developed to help architects and owners reduce their projects’ carbon footprints.

Unfortunately for architects, they generally have only minor influence over energy and carbon in their projects.  Some of the biggest contributing variables are not in the architect’s control at all: Does the project need to exist at all? How big is it? Where is it located? How meticulously are energy-consuming systems maintained? How many hours a day will it operate?  Architects have some influence over other considerations pertaining to energy (design of the building envelope, for example), but most of the hard work of calculating and designing energy efficiency performance is done by engineering consultants.  That left architects, who feel the need to participate in changing the world, a bit out in left field.  In an effort to bring the entire building design and construction community into the “green” conversation, the definition of “what is green” has expanded well beyond carbon and energy and into site considerations, material sourcing, water efficiency, and indoor environmental quality.  These additional domains gave architects more areas to influence the decisions made on a project, and architects have actively participated in expanding their services to fill those arenas.

The problem is that for carbon and energy, results are comparatively easy to measure.  Basically, you count up how much fossil fuel and non-renewable electricity was used during a given time period operating the building.  Same thing goes for water.  But for indoor environmental quality, you quickly get into subjective value judgments over things like natural light and views, and into fear-mongering and questionable science over chemicals in building materials.

On April 6, AIA Chicago and USGBC Illinois co-presented a program called “Mindful Materials: Education & Advocacy.”  The program was marketed to ask participants to “join AIA Chicago and USGBC-Illinois … to explore how to distinguish greener and healthier materials faster to serve your projects better. The Chicago design community has come together to endorse a voluntary product labeling initiative, dubbed Mindful Materials, to facilitate the transition to transparency, sustainable and healthy product selections for your projects.”  

The mindful materials initiative is simply just that – a labeling program and spreadsheet that materials librarians can use to track which products have health product declarations or Declare labels or are Cradle to Cradle certified.  To talk up the value of the labeling program, the speakers acknowledged that architects and designers are not chemists and are not trained to understand the medical literature, but somehow still equipped to understand what’s good and what’s bad sufficiently well to tell their clients that they can make their buildings more healthy.

The science is particularly equivocal on the link between adverse health effects and most building products.  Even chemicals that carry significant health hazards may not be risky at all when properly managed to minimize exposure, used in small concentrations or used in combination with other products.  For architects to not only full-throatedly advocate for certain product attributes but also arbitrarily select products based on a ‘mindful’ label could be doing a serious disservice to their clients.  

Architects and designers can make themselves feel like they’re being “green” through the use of products based on product ingredient ‘transparency’ and claimed (but not substantiated) indoor environmental quality attributes, but it’s a wasteful distraction, like fiddling while Rome burns.  It may not feel as significant, but architects can make a far bigger “green” impact by understanding the energy codes, heat gain and loss, air, water and vapor movement, and how these things affect building envelope.  Then they can make informed design decisions accordingly.

ENERGY STAR for Commercial Buildings is Unreliable

 

mypgm3phMany people are familiar with the US Environmental Protection Agency (EPA)’s ENERGY STAR program as it pertains to consumer products.  The most ubiquitous place to see their logo is on home appliances.  The ENERGY STAR label on an appliance signifies that the appliance is supposedly more efficient than non-certified models.  There are questions about the reliability of the consumer ENERGY STAR program, but that is not a topic that will be explored here.

In addition to energy efficient products, the ENERGY STAR program offers advice to homeowners for ways they can improve the energy efficiency of their homes, from wall and window sealing to insulating to lighting, and more.  Their Home Advisor lets you create a profile of your home and get tailored recommendations for prioritized improvements.

Less well known, but growing in importance is the ENERGY STAR certified commercial buildings program.  On the program website, it’s described as follows:

ENERGY STAR certified buildings and plants meet strict energy performance standards set by EPA. They use less energy, are less expensive to operate, and cause fewer greenhouse gas emissions than their peers. Starting with the first ENERGY STAR certified building in 1999, tens of thousands of buildings and plants across America have already earned EPA’s ENERGY STAR for superior energy performance.

Currently, 21 types of facilities can earn the ENERGY STAR. Commercial buildings start by entering their utility bill data and building information into Portfolio Manager, EPA’s free online tool for measuring and tracking energy use, water use, and greenhouse gas emissions. Industrial plants start by entering key plant operating data into another set of free tools, called Energy Performance Indicators.

Specifically, to be eligible for ENERGY STAR certification, a building must earn an ENERGY STAR score of 75 or higher, indicating that it performs better than at least 75 percent of similar buildings nationwide.

Needless to say, scoring whole buildings this way is not so simple.  EPA scores different uses of buildings separately (schools are separate from malls are separate from hotels, for example), but what do they do about similar buildings in different climate zones?  How about retail stores open 24 hours as opposed to stores that close?  There are many variables in buildings beyond use group that affect energy usage.  Recent attempts to validate the claims the EPA makes, flat-out, that ENERGY STAR buildings use less energy, have shown the picture is not at all clear (at best) and are very possibly simply wrong.

Background

The EPA created the ENERGY STAR system for commercial buildings as a benchmarking tool to track and collect data on how buildings in the US were improving in efficiency.  They provided the Portfolio Manager tool that building owners can use to input data on their buildings.   The information collected includes location, use group, year constructed, technologies used and how much actual energy is either purchased or generated on site.  The EPA used this data to begin scoring buildings on its 1 to 100 scale in the late 1990s.  Since then, many municipalities and green building certification organizations have begun mandating that buildings be scored using EPA’s Portfolio Manager, and receiving ENERGY STAR certification is among the criteria to receive green building labels, which makes the reliability of the EPA’s scoring system critically important.

Current Research

In his paper, ENERGY STAR Building Benchmarking Scores: Good Idea, Bad Science published in the 2014 Summer Proceedings of the  American Council for an Energy-Efficient Economy John Scofield, Ph.D. scrutinized the methodology used by the EPA to assign ENERGY STAR scores, and found that it contains “serious flaws that lead to erroneous results.” The flaws in one model are so severe that Scofield demonstrated that random numbers produced a model just as convincing as the EPA’s model.

The main problem is that there are simply too few actual buildings entered in the comparison database for each building model (use group) and too many independent variables (location, occupancy, size, equipment, etc), and that in some instances a few hundred actual buildings are being asked to represent hundreds of thousands.  The database is not actually populated by information entered in the Portfolio Manager; instead it’s collected in a periodic survey by the Energy Information Administration.  When you look for buildings that closely resemble the target in terms of location and other variables, the number may be only in the teens.  To combat this, the EPA developed statistical models using predicted energy use.  These models are meant to represent a larger cohort of buildings, and new projects are compared against the model, rather than against actual buildings.

The statistical tools used by the EPA and Dr. Scofield are fairly advanced for a lay person – A detailed explanation of the EPA’s methodology and statistics is included in Scofield’s paper; a more lay-accessible description can be found in this video presentation.

Statistical models are imperfect and sometimes the independent variables make more noise than give good results.  In order to test how well the statistical model works, statisticians use the R2 measure, also called ‘goodness of fit’ to determine how well data fit a given statistical model. An R2 of 1 indicates that the regression line perfectly fits the data, while an R2 of 0 indicates that the line does not fit the data at all. A low value could result because you are trying to fit a line into a curve or you are dealing with known variables that do not truly predict the expected value (random or barely correlated to the dependent variable).  So the lower the R2, the higher the uncertainty of the predicted results is.  Another reason why this number can be small is that you do not have enough experience (observed instances) to give you credibility in your model.

Scofield’s paper finds R2 to be as low as 0.33 for some of the models, so the ENERGY STAR scores are extremely uncertain and offer minimal improvement over random guesses.

Conclusion

Making recommendations for improving the statistical tools used to score buildings is beyond my math knowledge.  I had to survey two friends (one a math teacher and the other an actuary) to get to the point where I barely understood the statistics tools used in the scoring method.  As for recommendations, Scofield says, “I would encourage people to continue scoring their buildings with the EPA’s Portfolio Manager simply as a useful way to track the variation of their own usage over time.  Usually these variations are tied to variations in energy use not variations in building operating parameters — and these are not subject to EPA errors.  As a tool for comparing your building to others in the stock it is less useful — and that is where it is subject to the errors and uncertainties in the EPA model predictions.  I am not optimistic that these will get better anytime soon.”

Until the models and tools are vastly improved, “ENERGY STAR Certified” should be considered to be a marketing gimmick and not a true measure of efficiency.