Residential Green Building Committee: 5/8/2017 Recap - All About Net-Zero Design!

By Molly Cox on 5/9/2017

The Residential Green Building Committee (RGBC) met on May 8th, 2017. We had a guest presentation from Stephanie Horowitz, Managing Director of ZeroEnergy Design. ZED is a green architecture and energy consulting firm, working in the fields of architecture, mechanical engineering, and finance.

With a strong 7 person team, ZED is committed to designing homes and buildings that use 50% less energy than building code requires. Stephanie explained that most of their project makeup consists of single-family homes, compared to multi-family homes. They are also on track for the 2030 Challenge, which they started tracking in 2010 for their own projects.

When designing for most energy efficiency for a building, ZED prioritizes the building envelope first, followed by systems, and then renewables. ZED uses PHPP (Passive House Planning Package) for energy modeling of their custom home projects, but not all projects are expected to earn Passive House certification. The Energy Use Intensity (EUI) values for ZED’s completed projects are published on their website.

Stephanie showcased a Net Positive, LEED Platinum Certified four bedroom home in Lincoln, MA. This home has an impressive score of 0.27 ACH50 (Air changes per hour), which is a 90% reduction from code. ZED implemented systems such as air source heat pumps and renewables with a 13.1 kw solar PV array. She emphasized the importance of the direction the solar PV array faced, as that can hugely impact the EUI (south facing solar array is the best). It was impressive to see how closely aligned the monthly PV array predicted usage (performed by PV Watts) was with the actual usage. The homeowners are taking advantage of net metering in MA, to use the credits from the array’s overproduction in the warmer months, for the winter months when PV production is low.

In other news, the USGBC MA Chapter has a building tour of the Martin Luther King Jr. School on May 17th (register HERE), and a tour of Fort Hill on June 7th (register HERE). Come join us for our next RGBC meeting on June 12th!

See Stephanie's presentation slides here.

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