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Joanna Grab is a Senior Sustainability Consultant specializing in a range of multifamily residential green building certification support including Passive House, LEED for Homes, and ENERGY STAR programs. She has 7 years of experience collaborating on green affordable housing projects. Her expertise in several energy modeling software programs assists project teams in making informed cost effective decisions.

Posts by Joanna Grab

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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How to Implement an Efficient Lighting Strategy in a Multifamily Passive House

Walking the aisle of your favorite home improvement store, you’ll notice the wide array of options for very efficient light fixtures. Don’t be fooled – truly efficient lighting design is achieved through thoughtful layout and proper controls.

Hallway lightingA high performance building warrants an efficient lighting strategy. With so many efficient LED fixtures available on the market, individual fixture efficiency is rarely an issue. However, these fixtures are often placed in high concentrations or at a higher wattage than necessary to adequately illuminate a space. The result is high lighting power density (LPD), which is measured by dividing the total light fixture wattage in a room by the square footage of that room. Even with controls such as occupancy or vacancy sensors, high LPDs are especially energy intensive in frequently occupied common areas, e.g., corridors and lobbies of multifamily buildings, impacting the bottom line efficiency of all buildings.

Projects pursuing Passive House certification are impacted by an optimized lighting scheme more so than a code-built building. As the heating and cooling energy used in a Passive House building decreases due to an excellent thermal envelope, the ratio of lighting energy used increases. Reducing lighting energy use can drastically improve the building’s overall primary energy demand. (more…)

Pathways to Passive House Certification

Passive House logosDid you know that there are two pathways for earning Passive House certification? There’s Passive House International (PHI) and Passive House Institute US (PHIUS). Using an energy modeling software, both programs evaluate a building based on a variety of factors. Despite the misleading moniker, certification is not limited to just housing. In fact, building types from residential and commercial high-rises to industrial factories have earned Passive House certification around the globe. However, the two certification programs are run by separate institutions, using different energy modeling software and standards. However, both ultimately maintain the shared goal for high performance, low energy buildings.

Historically, around 2013, the PHIUS organization developed a new standard called PHIUS+ 2015 with a climate-specific approach and an alternate modeling software. Starting in March 2019, PHIUS projects will be held to updated requirements under the PHIUS+ 2018 program.

PHI also offers project and climate specific cooling demand thresholds, having previously begun offering alternate certification options in 2015. Additionally, PHI created a program called EnerPHit to provide more flexibility for retrofits. PHI recognizes buildings that exceed its standard certification by offering Plus and Premium certification, as well as a Low Energy Building certification pathway for projects that are near PH efficiency.

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