E+ and Net-Positive Development Seminar

By Jen Cole

Did you know Boston is committed to being carbon neutral by 2050? John Dalzell, Sr. Architect for Sustainable Development, gave a fascinating presentation this morning on E+ and Net-Positive Development that will help us get to this prestigious goal. We had a packed room with both new and familiar faces all eager to hear what's new with Net Zero Building operations in Massachusetts. The USGBC MA is devoted to bringing together practitioners, engineers, and architects alike in order to move forward with net-zero planning in our state. We heard of many various examples this morning of projects that were successful in constructing net energy positive buildings such as the Highland Park projects.

In order to achieve net -zero, the key aspects of the building to focus on are the envelope, the orientation, site, and the mechanical systems. The envelope must be air tight and incorporate 12 to 14-inch walls so that the temperature inside is stable throughout the day. Even if there was a power outage, a tight envelope would secure the building with one to two degrees of temperature variation without heating or cooling. Proactive testing such as the blower door test is done during construction phases to check the air tightness and ensure that there is no leakage. The orientation of the building is also a very important aspect because the use of solar panels is the predominant energy source. Net-zero buildings must be oriented so as to maximize the slope of the solar panels to the south side and allow for south facing recess windows with overhang. The windows themselves are also important to have with triple-pane glass for best insulation. Mechanical systems for net-zero buildings will most likely be smaller highly efficient mini split systems. These compact systems contribute to the building's efficiency by heating and cooling individual rooms while they are being occupied compared to a larger central system that requires more time and energy to heat/cool larger spaces. In addition to the mechanical systems, orientation, and envelope efficiency features such as low-flow water fixtures, air source heat pumps, taped sheathing, and passive ventilation all contribute to the zero net energy of the high-performing building.

A huge take away that John left with us this morning is that a building team must work together efficiently on new projects in order for them to be the best they can be. Achieving a net-zero or net-positive building is not a difficult nor expensive task if a team is designing, constructing, and working smart on the building's features and communicate well on all of the several sustainable aspects that make the building high-performing. Performance monitoring is critical throughout every stage of construction to evaluate how a building is holding up to the desired outcome.

We cannot thank John Dalzell enough for sharing with and inspiring our community to push forward with net-zero and net-positive projects. Boston, a national leader in green building, is promoting the next generation of high performance deep green buildings. The E+ Green Building Program demonstrates the feasibility of regenerative multi-unit residential buildings and brings energy and environmentally positive homes to Boston’s neighborhoods. Stay updated with the USGBC MA for more news on the net-zero movement!