NESEA Pro Tour at Multifamily Gut Rehab in Cambridge

On Friday May 19th, ZED joined Northeast Sustainable Energy Association (NESEA) in leading a BuildingEnergy ProTour of a 3-unit triple decker in Cambridge that underwent a gut rehab after a fire in 2020. The project was developed by Homeowners Rehab Inc (HRI) and now provides three apartments for low-income residents.

Erika DeRoche of ZED kicked off the tour with a 45-minute overview of the project, which was then followed by a three-stage tour of the basement, exterior, and interior of one unit. Erika DeRoche from ZED, Deliandro Cruz of Alpha Smart Builders and Nate Wickman of New Ecology, Inc. hosted each station, talking about the finer points of this ambitious energy efficient renovation. Attendees were able to hear about design decisions around HVAC, Domestic Hot Water and Fire Protection systems, as well as the wall and flooring assemblies, all of which prioritized resident comfort and sustainability.

We are incredibly proud of this project and the work of all of our partners and collaborators that made it come together so successfully. Our hope is that this type of retrofit - all-electric, no combustion on site, high efficiency systems and super-insulated envelope - will serve as an example of not only what is possible for this building typology, but also what should become the norm for future projects.

Learn more about this project: Columbia Street Residences

More images from the tour here.

Backstage at a Blower Door Test

Building diagnostics and commissioning is standard procedure at ZED, which includes blower door testing at key stages in the construction process. Blower door testing is a crucial aspect of putting together the building envelope correctly, helping ensure an airtight home. An airtight air barrier not only prevents cold or warm air from getting in, but also moisture, dust, pollen and other contaminants to entering the home.

What does a typical air barrier look like?

We perform blower door tests at multiple points during construction to ensure success. At our Columbia Street Residences project in Cambridge we had to do this initial test without a completed air barrier in the basement but were in range of our target. New Ecology performed the test and found approximate air leakage to be 2.6 ACH50.

How a Blower Test Works
The blower door test is used to quantify the amount of air leakage through a building’s enclosure. A blower door fan is temporarily sealed into an exterior door or window, while all other exterior openings are closed, as well as all mechanical exhaust devices shut off. When the blower door fan is turned on, it creates either a positive or negative pressure differential between inside and outside. This in turn forces air through any penetrations in the building enclosure it can find, which is what the blower door test measures. This air leakage results measurement called ‘air changes per hour,’ or ACH50.

Air Leakage (ACH50)
Air changes per hour (ACH) is calculated using a blower door at a standard pressure difference of 50 pascals (a unit of pressure) between inside the home and outside. A building's ACH50 therefore tells us that at the pressure of 50 pascals, air leaks from the building at a rate of X times the volume of the building per hour. For example, a leaky building might be 15 ACH50, while a high performance building is typically 1 ACH50 or less. The Passive House standard requires 0.6 ACH50 or less.

Architecture: ZeroEnergy Design
Mechanical Design: Ripcord Engineering
General Contractor: Alpha Smart Builders

In Progress: Multifamily Housing in Taunton

ZED has been working with the Taunton Housing Authority (THA) since 2020 to perform a comprehensive sustainable renovation of four scattered site low-rise developments with 24 units of multifamily affordable housing. Funded by DHCD Formula Funding and a Comprehensive Sustainability Initiative (CSI) grant, the goal was maximum energy conservation, emission reductions, and water use reduction. The result was significantly upgraded apartments with superior insulation, triple-glazed energy efficient windows, insulated doors, and optimized systems to improve the quality of life for THA’s residents.

Energy and Cost Reduction. Testing, site visits, analysis and cost estimating resulted in cost optimal improvements, including air sealing, extra attic insulation, new doors, continuous insulation, foundation insulation, high efficiency boilers, and toilet replacements. Air sealing and insulation was achieved by the installation of a Zip System R-Sheathing for 4 inches of total continuous insulation, taped air/water-resistive barrier, re-siding, and air sealing at vented attics. At the Martel Street development, the fieldstone foundation wall and rimboard was air sealed and insulated using low GWP closed cell spray insulation. This resulted in a 70.5% air tightness improvement between pre- and post-construction blower door testing.

Overcoming Challenges. Each of the four sites had unique conditions, however all shared the challenge of increased costs and elongated procurement due to COVID-19. Additionally, there was existing poor quality construction at two of the four developments, no access to crawl spaces under one development, and fully occupied residences during all renovations. At one development, Owner records showed that construction was completed in 1983, however closer observation indicated a far earlier vintage, such as balloon framing and heavy timber sill on fieldstone foundations. Re-siding and re-roofing were outside of the project scope, so ZED recommended 3” low VOC ccSPF insulation for the basement air sealing and insulation, allowing resident reentry within 6 hours; foam sealant plus blown cellulose insulation for the attic.

Zip system tape at flanged window creating positive drainage 

Zip-R insulated panel over 2” foil faced insulation and self-adhered air barrier

Foil faced insulation over continuous air barrier 

Cement board and stucco protection over foundation insulation board

Wall insulation inside porch roof

New low-maintenance, durable roofing and siding

Passive House Incentives for Multi-Family High-Rise Buildings

Mass Save recently announced financial incentives and assistance to support the construction of multi-family high-rise buildings with Passive House certification or similar levels of energy efficiency.

Why Passive House?

Passive House Building techniques provide the occupants with shelter from rising energy costs through a building envelope that requires only a fraction of the heating and cooling energy consumed by a typical new building. The super-insulated structure eliminates drafts and temperature swings throughout the building thereby ensuring maximum thermal comfort and also helps with noise attenuation by mitigating any surrounding outdoor noise. Additionally, houses built in accordance with Passive House standards require a smaller investment in mechanical systems and have a lower carbon footprint compared to buildings built to code.

Eligibility Criteria

The Mass Save Passive House incentives are available to projects that enroll prior to reaching 100% Schematic Design. Eligible buildings should be four stories or higher with at least five units and pursue Passive House certification and monitor and provide the Sponsors with whole-building gas and electric consumption as well as on-site production. A PHI or PHIUS-certified Passive House consultant is required to conduct a feasibility study and serve as consultant throughout the design and certification process.

Buildings will be eligible to receive post-construction incentives if they at least achieve pre-certification. If the building does not achieve pre-certification, you will be eligible for the standard Multi-Family High-Rise incentives.

Passive House Consulting by ZED

ZeroEnergy Design provides Passive House Consulting services for developers and architects seeking exceptional energy performance and targeting PHI or PHIUS+ certification.

ZED will guide building envelope improvements and mechanical systems to best accommodate project goals such as comfort, durability, indoor air quality, aesthetics, cost effectiveness, efficiency, and certification.

Depending on project goals and requirements, ZED can assist with:

• Passive House FEASIBILITY

• Passive House ENERGY MODELING

• Passive House PRE-CERTIFICATION AND CERTIFICATION FACILITATION

REQUEST MORE INFORMATION

PASSIVE HOUSE CONSULTING

Historic Multifamily Project Case Released

ZeroEnergy Design is proud to present a new case study for the firm’s mechanical design services, the Troy Historic Multifamily Project in the Central Troy Historic District of downtown Troy, NY.

While historic preservation and net zero performance might not seem like a natural fit, this project proves that it is possible to achieve high performance and energy efficiency in older masonry structures without sacrificing the architectural features.

The original Victorian-era structures consisted of two three-story walk-ups in vacant and heavily deteriorated condition. ZED’s responsibilities included specifying and designing efficient HVAC systems that would provide year-round thermal comfort along with a constant supply of fresh air, all with minimal impact on the building’s fabric and historic aesthetics.

Overall, the building achieved a 90% reduction in energy consumption compared to before the renovation.

The project was the result of collaboration between Second Arrow LLC, Neil Pelone Architecture, ZeroEnergy Design, RDH Building Science, LTRW Architecture & Preservation, Ethos Homes LLC, and Active Solar Development.

MORE: TROY CASE STUDY

RetrofitNY Solution Provider Team

Paul A. Castrucci, Architect together with energy consultant, ZeroEnergy Design, are pleased to announce their Solution Provider Team partnership and prequalification status for NYSERDA RetrofitNY initiative.
 
RetrofitNY is working to create new solutions to renovate multifamily buildings while achieving or approaching net-zero energy use and creating standardized and scalable processes that will improve residents’ comfort and buildings’ energy performance. 

MORE:  PRESS RELEASE