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Tag: Energy Efficiency

Integrating Social Equity into Green Building – Part 1: “Just Sustainability”

The causes of social inequity and injustice are deeply rooted within the systems that shape our society, including the built environment. The built environment represents the literal foundation of our society’s presence in the world – from the smallest rural community to the largest city. The way in which buildings are designed, constructed, and maintained has a tremendous influence on the equity (or inequity), and the justice (or injustice), of our society. The way we build and the strategies we employ can either continue to worsen social issues or can lay the groundwork for significant progress to be made on these issues in places around the world.

The building industry continues to make progress on reducing negative environmental impacts of the built environment. In fact, we’re increasingly seeing practices and strategies go beyond “sustainable” to “regenerative,” with such goals as net-positive energy, water, and waste. Now, the industry is reckoning with the urgent need to integrate social equity into its definition of sustainability in order to also reduce negative social impacts of the built environment. We might accelerate the process by framing the goal as “net-positive equity.” (more…)

Electrifying Central Ventilation Systems in Multifamily Buildings

A common strategy to provide ventilation in multifamily buildings is to design a central roof-top air handler that distributes outdoor air to each unit. The energy cost for this system, which commonly uses natural gas for heating for either a gas furnace unit or hot water from a central boiler is paid for by the building owner. However, there is another option – VRF[1]. With the unprecedented rise of VRF technology in the last decade combined with regulations such as New York City’s Local Law 97 of 2019[2] (carbon emission penalty), the industry is taking a giant leap towards building electrification. There are always questions and concerns raised against building electrification ranging from initial cost to operating cost to reliability of the VRF technology. From the owner’s perspective, the biggest question is usually surrounding the operating cost of an electric system compared to a natural gas system for heating, but the cost of ownership must consider multiple energy metrics. I was curious to understand the impact on various building energy profile metrics associated with a Dedicated Outdoor Air System (DOAS) using the conventional gas fuel source vs. the latest VRF heat pump technology using electricity in a multifamily building. The findings of this investigation challenge the deep-rooted notion that electricity, being more expensive than natural gas per BTU, will always cost more to operate.

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Pirelli Historic Retrofit: Part 1

 

image of Pirelli buildingOne 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, and Enclosures 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: A New Tool for Gut Rehabs?

Image of AeroBarrier eventAeroBarrier 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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The Numbers Are In! NYC Passive House Performance Data

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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Interesting Elements: A Modeling View on Net Zero Homes

I recently performed some net zero energy modeling on a single-family home for work. Around the same time, I got to chatting with my neighbor (mindful of social distancing) and when I mentioned net zero,  he said, “Is that even possible?” AH! Get the word out. We have the means to offset our home energy use. What follows are the basics to consider when trying to fully offset home energy along with a breakdown of how different upgrades can affect energy use.

There are lots of resources available on how to reduce home energy use. You can look at program requirements and guidelines like the Zero Energy Ready Program or Passive House. Through modeling I will demonstrate how the energy use numbers change and describe what we have seen in real-world examples of net zero homes. Net zero is not new and we’ll be looking at some specific pieces of single family home modeling.

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How to Talk Windows with a Passive House Nerd

Before we get into this topic, please take a few seconds to consider the following questions:

  • Do you plan to work, or have you ever worked, on a Passive House building? (If not, the rest of your answers are probably no.)
  • Has your Passive House consultant ever told you that the window U-Value you provided “won’t work in their energy model?”
  • Has your Passive House consultant ever told you that your window “doesn’t meet the comfort criteria?”
  • Have you ever scratched your head when someone asked you to provide the “Psi-spacer” for your window?

If you answered yes to two or more of these queries, please read on. If not, you’ll still learn some useful information, so why not continue?

If you’re still reading, then you are probably somewhat familiar with a “U-Value” and you may know what “SHGC” means. If not, no worries. This article will explain both, and by the end you’ll be able to talk about these terms with most Passive House nerds.

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Net Zero and Electrification

Net zero” can mean a lot of different things depending on what you choose to measure – zero energy usage, zero carbon emitted, zero lifecycle impact, etc.

At Steven Winter Associates, Inc. (SWA), we work with clients who are approaching net zero from different angles: driven by institutional goals, climate concerns, marketing campaigns, and connecting with municipal emissions targets. One thing we see over and over is that super high performance is difficult to achieve, but with a key simplification – there are not many ways to do it. All roads may lead to Rome but the closer you get, the fewer roads there are to take.

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Choosing Insulation for Carbon Value – Why More is Not Always Better Part 2

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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Passive House: An Alternative Compliance Path to Toronto Green Standard Tier 3

It is clear to see that the Passive House (PH) standard is here to stay! Across North America, more States, Provinces, and Municipalities are integrating PH into their building standards. One of the more recent adopters is the City of Toronto. In the most recent version of the Toronto Green Standard (TGS), the PH standard is offered as an alternative compliance path to TGS Tier 3, and with this alternative compliance path one obvious question comes to mind: What is the major difference in required component efficiency for a multifamily building in Toronto that is looking to meet either the PH standard or TGS Tier 3?

The PH standard is performance-based and is focused on decreasing whole building energy demand, improving building durability, providing optimal occupant thermal comfort, improving indoor air quality, and reducing carbon emissions. The PH standard reduces building operation costs, decreases carbon emissions, and supports an improved indoor environmental quality for building occupants. The TGS has similar goals and benefits when compared to the PH standard, and there are some obvious synergies in the program design between TGS and PH. The tiered energy category in the TGS takes a similar approach to PH by offering an annual budget for three different categories. For PH you must comply with a total energy budget for annual heating demand, annual cooling demand, and total source energy use intensity. Similarly, but slightly differently, the TGS offers a budget for total site energy use intensity (TEUI), annual heating demand or Thermal Energy Demand Intensity (TEDI), and the additional category of Greenhouse Gas Intensity (GHGI). In both standards, the path to compliance is non-prescriptive and designers can implement a variety of component efficiencies and system options. See table 1 and 2 below:

 

passive house standard criteria data

Table 1: International Passive House Standard energy criteria

passive house standard criteria data

Table 2: Toronto Green Standard Tier 3 energy criteria

 

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