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  • Writer's picturePeter VanderPoel

Weighing In-LEED vs PH

I recently started a weight loss program. For me, diets could be considered a chronic condition. It brings to mind the Mark Twain quote, “giving up smoking is easy; I’ve done it hundreds of times”.

My latest diet is an app-based version that has several components, but two, in particular, stand out. The first is the use of ‘coins’; these are provided as incentives to reward laudable behaviors: reading the material that underlies the system,  tracking meals daily, etc. Collecting enough ‘coins’ opens other modules or allows for an ‘off’ day. The second is the mandatory, daily, weigh-in.

These two methods reminded me of the two contrasting approaches to reaching energy efficiency goals in the construction industry: LEED and Passive House.

LEED, which stands for Leadership in Energy and Environmental Design, is by far the most popular of that ilk,  using a point-based system to track materials and methods that contribute to more energy efficient design and improved environments.

The second is Passive House(PH), a very strict accounting of expected energy usage using modeling software. This is  coupled with a demanding construction regimen and post construction verification.

In LEED, points are awarded based on a wide range of subjects such as: Light Pollution Reduction, Indoor Water Use Reduction, Minimum Indoor Air Quality Performance, Minimum Energy Performance, Optimize Alternative Materials, etc. with some items required and others optional. There are myriad combinations that can reach a certification level. Like the Olympics, success in meeting the points goal is awarded with a ‘medal’ rating: LEED Platinum, LEED Gold, etc.

With Passive House, success in this program is measured in energy use per square foot of conditioned floor space measured in kilowatt hours. There is leeway allowed in materials and methods but the standard is strict enough that shortcomings in any aspect of the envelope design or installation will likely result in certification failure.

The concern is that LEED relies on abstract ‘points’ and ‘medal’ levels which don’t translate into anything in particular. Like the ‘coins’ in my diet program, they are not linked to any concrete metric other than ‘better’. In fact, a study published in the Journal of Building Engineering found, in a Washington DC study, that

LEED office buildings do not perform better, at any of the certified levels. On the contrary, the reported LEED buildings collectively use 17% more source energy and 13% more site energy than non-LEED buildings. …(1)

The coin system in my diet program provides information and incentives which may or may not lead to weight loss. What’s the best way to track weight loss? Weigh yourself! Those coins felt good when they were awarded, but not if the trend is going in exactly the wrong direction

PH provides goals in the planning stage and demands proof post construction; its relative indifference to materials and other environmental quality factors doesn’t compare well with LEED, but for its single-minded goal of planning and executing substantial, verifiable energy reduction- it performs as advertised. LEED is undoubtedly a more wide ranging approach to a quality living/working environment, but the metrics can be squishy and, perhaps, leave escape routes from the hardcore goal of reducing energy use.

The variety of topics in the LEED menu brings to mind a disappointing meal. It was at a restaurant in Glasgow that boasted 5 different cuisines I don’t remember the lineup exactly but it was something like: Indian, Chinese, Thai, Vietnamese and Indonesian. I guess they could categorize it as South and East Asia, but still, it covered at least half-a-dozen time zones; the menu was as thick as an Orvis catalogue. I don’t remember what I got, but I did note that it was memorably unmemorable. My take-away was -trying to do many things often means not doing any of them well.

But the difference is more fundamental than coins vs pounds: it is piecemeal vs. holistic.

The LEED approach is serial; a literal checklist with seemingly unlimited variations possible. Those I’ve spoken with who’ve submitted LEED projects  readily admit that it is treated in the office as a box-checking exercise.

The practice of Architecture is, by its nature, a holistic practice. The French architect Viollet Le Duc had, in essence, described good design such that, “ anything added is superfluous, anything removed renders it incomplete”.  Teaching in University settings, when the topic of ‘sustainable design’ is the main focus of the program, I’ve found the most satisfying projects are those where the sustainability is integral-it cannot be excised with destroying the whole. The least satisfying, those that hang the technologies on an indifferent design; like ornaments on a Christmas tree.

Engineering, by its nature, readily admits of serial solutions; checklists where each element may be exchanged as long as the result meets the required metric, except that LEED appears to be falling short of the important energy metric.

The PH approach is strict enough that if any part is missing or substandard, the whole fails.

The coin system, while rewarding virtuous decisions, does not, by itself deliver one of the fundamental goals. I can attest to the fact that reading course material and logging meals does not necessarily mean I am losing weight.

Passive House has a demanding curriculum to achieve certification, but the payoff is an ability to understand and implement design decisions that produce verifiable energy savings. Its scientific approach is a heavy lift to incorporate into a practice, but the results are literally measurable and should be considered as the new “gold standard” for energy reduction in the construction industry.

(1) 2019 energy benchmarking data for LEED-certified building in Washington, D.C.: Simulation and reality. Journal of Building Engineering, Oct 2021 volume 42

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