Party Walls

 

One of the most important drivers in achieving Passive House certification (or achieving any goal!) is getting the project team involved from the start. Becker + Becker, the owner, architect and developer for the creative retrofit of the Pirelli Building, hired SWA’s Passive House, LEED, Enclosures, and Accessibility teams to coordinate during early design. Becker +Becker is invested in rebuilding for resilience, sustainability, and occupant health and comfort and appreciates the necessity of getting goals defined at the outset.

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AeroBarrier is touted as the best route to never fail another blower door test. The technology, which involves pressurizing a space with a blower door fan while misting a water-based glue into the air from multiple points throughout the space, is most often being used on new multifamily buildings after drywall is installed. SWA first experimented with the technique on the Cornell Tech high-rise building. Back in March, I reached out to Yudah Schwartz at SuperSeal Insulation, Inc. about a personal project, the gut rehab of a 2,500 SF detached single family home. While renovations aren’t something they normally do, Yudah and his team agreed to try a demo. Here’s what happened.

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In a collaborative effort that merged financing and energy use analysis, the New York City Passive House industry finally has performance data. Working together with Bright Power, The Community Preservation Corporation, and NYC Department of Housing Preservation & Development, this analysis is the first of its kind.

Why does this matter?

Energy Use Intensity (EUI) measures energy consumption on a per square foot basis to compare buildings and allows interested parties to gauge one building’s usage to another (or to a group of buildings with a similar use type). The study team compared the actual EUI of six completed Passive House-certified and Passive House-like buildings against recently completed multifamily code-built buildings. Information was gleaned from the EnergyScoreCards database and the Passive House (PH) target. The weather normalized data indicates the Passive House and Passive House-like buildings are performing much better than the comparable code-built group, but are not quite as efficient as the Passive House threshold. Industry leaders have recognized this performance gap – between predictive assumptions that rely on standardized patterns of use and the real-life habits of actual people living in the building. This gap has been a hot topic  at the past several New York Passive House conferences. The results from the current analysis provide a starting point now, so the industry can focus on strategies to continue to reduce EUIs.

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In Part 1 of this blog post, we highlighted two of the most commonly used insulations in the U.S.– XPS board and closed-cell polyurethane spray foam – and noted that they are produced with blowing agents (HFC-based) that are putting more carbon into the air during construction than they save during building operation for many decades. We left you with a question: if we don’t use these insulations, how can we make up for the loss of the helpful qualities that has made us dependent on them?

Insulation Alternatives

One part of the answer comes from the development of new materials. In Europe over the last decade, Honeywell developed a new blowing agent, a hydro-fluoro olefin (HFO), which claims a global warming potential (GWP) of less than one, which is less than that of carbon dioxide.  First in Europe, and now in the U.S., manufacturers such as Demilec and Carlisle are coming to market with a closed-cell polyurethane spray foam that uses this blowing agent instead of the HFCs that carry a GWP of well over 1,000. These spray foams have a slightly better R-value  than their high-carbon predecessors, and otherwise have the same qualities that make them useful in multiple contexts – air/vapor barrier capability, conformance to irregularities and penetrations, etc.  However, they also have many of the same downsides – high flammability, potential (and not completely understood) off-gassing post-application, and the basic fact that they are petroleum products.

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We took some common New Year resolutions and put our SWA spin on them. This year, make resolutions to improve the built environment in 2020!

 

1. Go on a (Carbon) Diet – diets are difficult, but as with all things, moderation is key. Reducing operational carbon use with super-efficient buildings is only part of the equation. We also need to understand the full Life Cycle of carbon use including building materials and products. Fortunately tools such as EC3 are making these analyses easier to understand; and products, including lower carbon insulation options and lower carbon concrete, are becoming readily available.
2. Quit Smoking – enforcing no smoking policies is one of the best strategies to improve the health of all building occupants. If you do allow smoking, make sure you develop a good fresh air strategy and compartmentalize your units with a good air barrier. And check out more of our strategies for healthy indoor environments.
3. Save More Money – lighting provides a significant area for savings. Sure, LEDs are great, but efficient design also means considering lighting power density (LPD). High efficiency fixtures placed in high concentrations still use a lot of energy and can result in over-lit spaces, which drive up upfront and operating costs. Lower your bills and the harsh glare with a smart lighting design.
4. Travel More – seek out hotels and restaurants that people of all abilities can navigate with ease. Access Earth is an app that tracks the accessibility of public spaces worldwide to help take the guesswork out of accessible accommodations in new locations.
5. Learn a New Skill or Hobby – looking to expand your horizons? Check out SWA Careers and join our team of change-makers to help develop and implement innovative solutions to improve the built environment.

 

 

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As members of the HERS Rating community, we are very excited about the recent study conducted by Freddie Mac determining that homes rated under RESNET’s Home Energy Rating System (HERS) between 2013 and 2017 sold for an average of 2.7% more than comparable unrated homes.

Using a national random sample, the property value analysis found that better-rated homes are sold for 3 – 5% more than lesser-rated homes. In this case the “better” rating means a higher energy efficiency rating. It’s unclear from the study if this means a home with an average HERS rating, such as HERS 55 in the Northeast, could be valued at 2.7% more than the unrated home. And perhaps one approaching Zero Energy, such as HERS 10, could be valued at 5% more than the lower-rated home. I could be doing some very creative math here, but doesn’t that imply that the better rated home might just be valued about 7.7% more than the unrated home?

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When I first started working at Steven Winter Associates, I didn’t know that one day I’d find myself involved in the development of codes and standards that impact how our buildings get built. I certainly don’t consider myself an expert, but I have learned a few things the hard way and thought they’d be worth sharing if you might be new to it.

So, here’s my very high-level summary of the code development process with respect to the 2021 International Energy Conservation Code (IECC), aka the “model” energy code. If you are looking for more detail, the ICC webpage has plenty of resources and a more detailed infographic than the one we’re showing and discussing here.

 

 

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ICYMI: The code change proposals for the 2021 IECC are open for voting by Governmental Member Voting Representatives (GMVR) from Monday, November 18^th through Friday, December 6^th, and your vote is instrumental in making buildings consume less energy! [Need a quick refresher on the code process? Check out our blog post here!]

Does your vote even matter?

Overall, there are not actually that many voters on a given proposal. In the energy proposals, last cycle, it ranged from about 200-400 voters per proposal, even though there were a total of 1,247 voters on the Group B codes, which includes the IECC.

 

So a small handful of voters can entirely shape the future of the energy codes that dictate how energy efficient our buildings will be! If history repeats itself, while some online voters tend to align with the Committee, many online voters align their votes with those cast by their fellow ICC voters at the Public Comment Hearings. This happened 81% of the time in 2016. Unlike 2016, in this cycle all the electronic votes cast during the Public Comment Hearings will be rolled into the online vote tally (although those voters can still change their vote).

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As part of the Climate Mobilization Act, and in accordance with the its greater carbon emissions reduction goals, New York City passed Local Laws 92 and 94 in April 2019, mandating the installation of rooftop solar photovoltaic systems and/or green roofs on buildings across the city. The new requirements will go into effect on November 15, 2019 and will apply to all new buildings and any existing buildings completing a full roof deck or assembly replacement.

The Mayor’s Office estimates that the solar and green roof installations mandated by these bills will result in 300 MW of new solar capacity, 15 million gallons of new stormwater management capacity, 1 million tons of greenhouse gas reductions, and hundreds of green jobs. Based on these projections, this will account for close to 2.5% of the city’s overall emissions reduction goals.*

The laws require that solar and/or a green roof be installed on all available roof space. Areas deemed “not available” and excluded from the requirements include:

• Areas obstructed by rooftop structures, mechanical equipment, towers, parapets, guardrails, solar thermal systems, cisterns, etc.;
• Fire access pathways and zoning setbacks;
• Recreational spaces that are recorded in the Certificate of Occupancy.

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SWA’s Enclosure Group is acutely aware that insulation is the most important single material choice to maximize the enclosure’s thermal resistance over its operational life. Many of us in the building industry believe that, combined with a good continuous air seal, the highest insulation value makes the greenest enclosure, helping to reduce a structure’s carbon footprint and combat climate change. It may come as a surprise, then, that some of the most commonly used insulation materials are so carbon-heavy to manufacture and/or install, that for many decades they wipe away the carbon-energy savings they are supposed to provide.  The following is a detailed discussion of how and why this is, and what the industry is doing to change the equation.

Embodied vs. Operational Carbon

The built environment looms large in the climate picture, because almost 40% of the total carbon put into the planet’s atmosphere each year is attributed to buildings. Over the past 30 years of green building, we have overwhelmingly focused on operational carbon – the carbon that buildings emit as they are being used. Only recently have we begun to focus on embodied carbon – the carbon that goes into constructing buildings, which is typically far greater than the energy saved in the first decades of operation. Changes in energy codes are aimed at operational carbon, and even those organizations and standards that have been at the forefront of promoting sustainable building [LEED, PH] have not been quantifying or limiting embodied carbon, although they bring attention to it.

The Time Value of Carbon

Assuming that a building stands for many decades, or even centuries, its operational carbon will eclipse its embodied carbon over its lifetime, and therefore when the building’s carbon Life Cycle Assessment (LCA) is calculated, operational carbon savings will be more important than embodied carbon saved/spent in the long run. Why does embodied carbon deserve equal weight with operational carbon? Because of the total global carbon emissions from buildings, 28% is pegged to embodied carbon. That’s already a large percentage, but when you consider the near term, the first 30 years of a building’s life, the percentage jumps to about 50%. In effect, every new building is in carbon debt upon completion due to the huge amount of carbon emitted  in order to construct it., And in order for the climate to benefit from the energy savings provided by a well-insulated and sealed enclosure and a high efficiency energy system, the building needs to last and be used for a very long time. The problem is that we may not have 30 years, let alone 60, to pay off that carbon debt.

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