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Project Description:
The Zero Energy Modular Affordable Housing Initiative (ZE-MAHI) installed two zero energy homes in Florence, MA. Zero Energy Modular (ZEM) construction creates healthy, durable, factory-built homes. These homes can be both single family and mobile and manufactured home replacements. ZE-MAHI is a program of the Massachusetts Department of Energy Resources; through ZE-MAHI, ten ZEM homes will be installed across Massachusetts. The two Florence homes are the program's first installations. Construction was completed in September of 2019. ZE-MAHI provided program incentives to help offset the purchase price of the homes. Local utilities provided additional incentives. Pioneer Valley Habitat for Humanity acted at the developer for both homes, which are now owned and occupied by income-eligible families.
The homes feature ultra-efficient design and appliances (cold climate heat pumps, ventless dryers, advanced heating and ventilation systems) and rooftop PV sized to meet the modeled consumption of the homes.
Additional phots are available here: https://www.energy.gov/eere/buildings/doe-tour-zero-glendale-road-modula...
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Occupancy Type and Details:
Owner occupied
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Materials:
The home was built with low-emission wood products, finishes and fiberglass, and EPS foam insulation.
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Gross annual production as reported on monthly utility bills.
Subslab assembly:
n/a - Insulated R-40 floor over unvented crawl
Above grade wall assembly:
Above grade walls are 2x4 double stud, 24 o.c., blown fiberglass.
Frame floors over an unvented crawl space are 9.25" TJI, 16" o.c., blown fiberglass with an R-value of 40.
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Process:
Outside dimensions of the home are constrained by the maximum vehicle size on roads. Pioneer Valley Habitat has been working to cost optimize a single family home by designing a "big enough" home. The design team at the modular factory suggested a conventional layout with three bedrooms on the second floor. To increase 'visitability' the developer's architect reworked the layout to put a bedroom, powder room and laundry on the first floor. The final layout has two "living rooms" to better distribute activities throughout the house.
Design for Adaptability:
This home has elements of "visitability". On the first floor is a powder room, bedroom and laundry.
Energy Modeling Software:
Ekotrope
Finances Description:
The solar PV was donated by solar installer PV Squared. Volunteer labor was used for on-site finishing work.
Total Cost of Project:
State incentives:
$50,000 per home through the Zero Energy Modular Affordable Housing Initiative
Utility incentives:
$1,133 per home
Energy Strategies:
The home has a tight envelope and high-efficiency mechanical systems and appliances to minimize energy use. It is equipped with rooftop solar to offset energy use on an annual basis.
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Summary of enclosure strategy/description:
Exterior air barrier and superinsulation. Insulated floor, R-40, over sealed crawlspace.
Roof Assembly:
Roof assembly is constructed with 11.25" Neopor SIP's with an R-value of 59.
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Door Description:
One 1/4 lite 24 sf door with a U-factor of 0.19 and one 1/2 lite 26 sf door with a U-factor of 0.23.
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Team Members:
Megan McDonough, Pioneer Valley Habitat for Humanity
Brien Tal-Baker, SimpleCity Studio
Li Ling Young, VEIC
Alison Donovan, VEIC
Mechanical Equipment Installation Details and Comments:
Point source heating and cooling with fully distributed balanced ventilation. Ductwork is installed in a sealed chase within the pressure boundary of the building.