Passive House Design
in Boston & Massachusetts
Most homes in Massachusetts work too hard to stay comfortable. A Passive House is designed so they don’t have to.
No drafts. Even temperatures, room to room. Air that stays clean year-round. A home that performs in January and July, without the systems running all day to make it happen.
ZeroEnergy Design (ZED) is a Boston-based architecture and mechanical design firm with five Certified Passive House Consultants on staff. For over 20 years, we’ve designed and certified Passive House projects across Massachusetts and beyond—from single-family homes to multifamily buildings, from new construction to deep energy retrofits. Each project is shaped by its site, its climate, and the people who live there. For us, it’s not a specialty. It’s how we design.
What is Passive House Design?
Passive House is the most rigorous energy performance standard in residential architecture. A Passive House uses up to 90% less energy for heating and cooling than a conventionally built home. It achieves this not through complex technology, but through careful design.
The building itself does most of the work, and the result is a home that is quieter, more comfortable, healthier, and dramatically more efficient – without compromising on aesthetics.
ZED’s five principles make it work together and nothing functions in isolation—they operate as a system, and that's exactly how we design them.
01: Siting and Orientation
Before anything is drawn, the site tells us where to begin. How the sun moves across the property. Prevailing wind direction. The home's position, its form, the placement of windows - these are the first passive steps toward reducing energy demand. In New England, where winter sun angles are low and summer sun is high, getting this right changes everything about how the house performs and how it feels to inhabit.
02: Super-Insulated Building Envelope
Performance starts with the envelope: walls, roof, and foundation working as one continuous system. We design with a continuous layer of insulation that wraps the entire structure without breaks, eliminating the weak points where heat escapes. The result is a home that holds its temperature with remarkable stability, whether it's 5°F or 95°F outside.
03: Airtightness
A conventional new home might achieve air leakage rates of 3–5 air changes per hour. ZED's certified projects have achieved airtightness as low as 0.2 ACH50 - that’s more than 90% better than code. That level of airtightness means superior energy efficiency, thermal comfort, building durability, and keeping outdoor allergens where they belong.
04: High-Performance Windows
Triple-pane windows eliminate cold spots at the glazing, so sitting near a window in January feels no different than anywhere else in the room. They reduce condensation, limit exterior noise, and allow for larger openings without an energy penalty, bringing in more natural light and strengthening the connection to the landscape.
05: Balanced Ventilation with Energy Recovery
An airtight home needs a mechanical ventilation system to provide excellent indoor air quality - and that's a feature, not a limitation. Energy Recovery Ventilators continuously supply filtered fresh outdoor air to every room while recovering 80–90% of the energy from the air being exhausted. Consistent fresh air in every room with almost no energy penalty.
Why build a passive house in Massachusetts?
Massachusetts isn't catching up to Passive House design. It's leading it.
The state's energy codes now require new homes to be zero energy ready. Over 300 municipalities have adopted it. Boston's net-zero carbon zoning is already in effect for new large buildings. The performance standard that ZeroEnergy Design has been designing to since 2006 is becoming the floor, not the ceiling.
Mass Save offers financial incentives for passive house construction in Massachusetts - support that meaningfully offsets the cost premium of building to this standard. In addition, the Massachusetts Clean Energy Center has invested in building the state’s workforce of certified Passive House professionals—expanding the pool of builders equipped to execute it correctly.
The New England climate makes designing to the Passive House standard especially effective. Long winters, heavy heating loads, increasingly humid summers, and the occasional power disruption from a nor'easter or ice storm. A passive house addresses all of it: dramatically reduced heating and cooling demand, continuously controlled ventilation through every season, and a super-insulated envelope that keeps the home comfortable for days without power if it needs to.
ZED has been designing Passive Houses in this region since before the term was common in the U.S. The climate, the codes, the incentives, the local builders who know how to execute - we understand all of it because we've led it from the beginning.
How ZED Designs Passive Houses
When architecture, mechanical design, and Passive House consulting work as one team from the start, it changes what’s possible.
At ZED, the team that designs your home is the same team modeling its energy performance. The architect specifying your windows and the mechanical designer sizing your heating and cooling system are in the same conversation from the first meeting. Nothing gets handed off. Nothing gets lost between disciplines.
We simulate how your home will perform using specialized passive house modeling software (PHPP and WUFI) from the earliest design stages - testing envelope assemblies, window configurations, and mechanical options before a decision is finalized. We guide contractor selection and stay present through construction, conducting site visits and overseeing airtightness testing to verify the build matches the design.
A Passive House that performs on paper but not in the field isn't a Passive House. We stay involved to make sure it gets built right.
Our New England Certified Passive House Projects
Stow, MA
A 4,715 SF home designed for every stage of life—single-story, aging-in-place ready, oriented to golf course and conservation land views, with a regionally inspired gable form and blue shou sugi ban ceilings that nod to classic New England craftsmanship. All-electric, net positive energy.
pEUI: -4.3 kBtu/sf/yr · Air Leakage: 0.038 CFM50/ft² · PHIUS Zero Certified
Awards: AIA Central MA 2025 Excellence in Design Award · PHIUS Passive House Projects Design Award
Acton, MA
A 1,473 SF home in the woods, designed for high performance without excess - simple shed roof, modern aesthetic, polished concrete floors, and a wall of glass that wraps the southeast corner to bring the forest inside. All-electric, net positive energy.
pEUI: -3.81 kBtu/sf/yr · Air Leakage: 0.049 CFM50/ft2 · PHIUS Zero Certified
Awards: Phius Passive Projects Competition — Source Zero Category · AIA Central Massachusetts Merit Award · PRISM Awards Silver Medal
Norwich, VT
A 2,700 SF home with a carefully balanced blend of features. The result is a final design that has an efficient footprint, meets the Passive House Standard (PHIUS+ Certified), and takes the form of a traditional farmhouse with some modern twists both inside and out.
Gabled roof lines with modern exterior detailing, lofted second floor and root cellar for energy-free food storage.
pEUI: 4.51kBtu/sf/yr · Air Leakage: 0.49ACH50 · Passive House Certified (PHIUS+) · Energy Star Certified
Frequently Asked Passive House Questions
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Yes. Deep energy retrofits - bringing existing homes to passive house performance levels - are a significant part of ZeroEnergy Design's practice and an increasingly important part of Massachusetts' climate strategy.
The approach involves improving the building envelope (adding exterior insulation, replacing windows, sealing the air barrier), upgrading to high-efficiency all-electric mechanical systems, and adding balanced ventilation with energy recovery.
Working with existing structural conditions adds complexity compared to new construction, but the performance outcomes can be remarkable.
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A passive house is a building performance standard focused on reducing energy demand - it's about how little energy the home needs.
Net zero is an energy balance - producing as much renewable energy as the home consumes annually, typically through solar.
And they're complementary.
A passive house makes net zero dramatically easier and more affordable to achieve, because when you reduce demand by 50% or more, a smaller solar array covers the rest.
ZeroEnergy Design frequently designs homes that achieve both - passive house performance with enough on-site solar to reach net zero or net positive.
Our firm takes its name from that goal.
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Building to passive house standards carries a modest premium over conventional construction. But it’s one that shrinks considerably when you're working with a builder who knows how to execute it.
For a custom home in Greater Boston - where construction costs currently range from $500 to $1,000+ per square foot - that premium represents a modest increment on the overall investment.
It's offset by significantly lower operating costs, reduced mechanical system complexity, Mass Save incentives for passive house construction, and the long-term durability of a super-insulated, airtight structure.
What you're investing in is a home that protects and holds its value. The cost question, for most of our clients, answers itself.
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ZeroEnergy Design has five Certified Passive House Consultants (CPHC) on staff, credentialed through PHIUS - the largest passive building certification body in North America.
This is among the highest concentrations of passive house expertise at any residential architecture firm in New England. Our team holds additional credentials in LEED and Energy Star.
ZeroEnergy Design has been named a Top 50 firm nationally for sustainability by Architect Magazine and Best Sustainable Architect by Boston Magazine.
Our projects have been certified under PHIUS+ 2018, PHIUS+ Source Zero, and Energy Star programs.
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Yes - and that relationship is critical. Passive house performance depends on precise execution in the field.
ZeroEnergy Design helps clients identify and select builders experienced in high-performance construction, provides detailed construction documents specific to passive house assemblies, and conducts active construction administration: site visits, airtightness testing oversight, and reviewing builder details throughout the build.
We don't hand off drawings and step back. We stay involved through completion to make sure what was designed is what gets built.
That oversight is part of what a passive house certification requires - and part of what we always deliver.
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ZeroEnergy Design is headquartered in Boston's Financial District and works with clients across Greater Boston, Massachusetts, and New England.
Our passive house projects include homes in Acton, Stow, Concord, Brookline, Somerville, Wellesley, Dartmouth, and beyond - as well as projects in Vermont, Connecticut, Rhode Island, and New York.
Whether you're building on a suburban lot west of Boston, a coastal site on the South Shore, or a rural property in northern New England, we design for the specific conditions of your site and region.
The New England climate is where we've built our expertise.
Ready to design your Passive House?
Whether you're building new or considering a deep energy retrofit, we welcome the conversation.
Tell us about your project - where you're building, what you're trying to create, and what matters most - and we'll share how ZeroEnergy Design's integrated approach can help you create a home that's as beautiful as it is healthy.