Ready to live green? The greenest home in Seattle is on the market

Ready to live green? The greenest home in Seattle is on the market

Photos courtesy Dwell Development

The first speculative Emerald Star certified home in Seattle goes net zero energy with solar panels and innovative building science.

Residential developer Dwell Development LLC combined cutting-edge green technology, renewables, and reclaimed materials to help the 2,218 square-foot home meet the rigorous requirements for Emerald Star certification developed by the Built Green residential building program.

The Built Green certification program was developed to establish environmental standards for construction materials, energy efficiency, water use and indoor air quality. The voluntary program requires builders to follow a specific set of criteria to attain a Built Green rating ranging from 3-Star, 4-Star, 5-Star or Emerald Star.

 Dwell Development is the only residential developer in Washington state that exclusively builds 5-Star Built Green homes and is leading the charge for green building certification in the region with the completion of the Emerald Star project, Dwell Development’s 100th certified home. Emerald Star certified homes are required to achieve net zero energy using a renewable source such as solar or wind. Other requirements include 70% reduction in water use, 90% reclaimed or FSC certified wood materials, and exceptional indoor air quality.

In order to meet Built Green’s renewable energy requirement, Dwell Development brought in local experts, Puget Sound Solar, to configure and install 6.6kW of photovoltaic panels on the roof. “The key to zero energy home building is to properly insulate and seal the home so heat and air are not lost through cracks in the building envelope,” said Anthony Maschmedt, owner of Dwell Development.

The Emerald Star features advanced framing, insulation, and high-performance Euroclime wood-framed windows and doors creating an airtight seal impervious to leaks and city sounds. Inside, the Zehnder Heat Recovery Ventilation (HRV) system works around the clock to expunge stale air and fill the home with fresh, clean air, while also maintaining a comfortable temperature year-round.

Showcasing Dwell Development’s commitment to pushing the envelope of sustainable building, the team installed a 450% efficient hot water heat pump from Australia to provide hot water and in-floor radiant heat, “this system is revolutionary for the industry. The Sanden uses 1kW of energy to generate 4.5kW of heat, that’s 78 percent less energy compared to traditional hot water systems.

"Not only is it better for the environment, its better for the homeowner’s bottom line,” said Anthony Maschmedt.

Reclaimed materials were carefully sought out to adhere to the Emerald Star certification requirements. The home’s framing package is FSC certified wood, which is a rare feat in residential building because finding a local supplier can be challenging and expensive. The home’s exterior siding is reclaimed Douglas Fir and naturally weathered steel roofing panels from a cannery in Oregon’s Willamette Valley, which also act as a protective rain screen. The floors, stairs, and treads were built out of 100-year-old hand sewn mixed hardwoods from Montana creating a stunning combination. Countertops, cabinets and tile made locally from high-recycled content contribute to the home’s impressive inventory of eco-friendly materials.

Building an energy efficient home of this caliber requires a smart and strategic architectural layout. Dwell Development partnered with local firm, Caron Architects, to design the three-story home in Seattle’s vibrant Ballard neighborhood. The Dwell Development team carefully configured the roof and window placement to maximize solar gain without sacrificing modern aesthetics. The urban location fulfills another Built Green requirement; the home must be within a half mile of at least five essential services. This is a requirement meant to minimize the use of cars for everyday errands; but in the case of longer trips, the built-in EV charging conduit is there to support a more sustainable lifestyle.

Dwell Development’s holistic approach to sustainable building helps homeowners conserve resources and cut costs while also setting the bar high for other residential developers. As more and more homeowners are investing in green upgrades, Dwell Development’s homes come standard with energy efficient lighting, technology and appliances. Emerald Star certification is the next step for sustainable building and with Dwell Development leading the way, zero energy homes will become the standard.

Project info

Square Feet: 2,218

Architect: Caron Architecture

Contractor: Dwell Development

Structural Engineer: Carissa Farkas

Landscape Design: Root of Design

Energy Modeling Third Party Verifier: Tadashi Shiga, Evergreen

Certified Third Party Verifications: Built Green Emerald Star (pending)

Renewable Energy Source: 6.6kW of PV on roof

HERS Score: 0 or lower (pending)

Blower Door Test Result: 1.17 ACH 50

Built Green is an environmentally-friendly, non-profit, residential building program of the Master Builders Association of King and Snohomish Counties.


General Requirements

  • Use integrative design process (scope may vary based on project size)
  • Encourage consumer education and marketing
  • 4000 s.f. unit max, excluding garage and multifamily buildings
  • Project must be within 1⁄2 mile of at least 5 essential services


  • Design and build to achieve net zero energy using approved modeling protocols
  • Clean energy production (e.g. wind, solar) must be on-site, or within 1⁄4 mile (may not be achieved through RECs)
  • Blower door test to achieve 2.4 ACH50 or tighter
  • Install energy use monitoring equipment and black/white switch for phantom loads
  • Waiver signed to share utility bill data (Multifamily must use EnergyStar Benchmarking database)
  • If building garage, provide wiring and run a minimum of 30 amps circuit to garage for alternative fuel vehicle charging
  • For multifamily projects, 3% of parking stalls must have alternative fuel vehicle charging stations
  • Commission building systems (scope may vary based on project size)

Water Use

  • Model to achieve 70% reduction in occupant water using baseline of 67 gallons per person per day
  • Achieve a minimum Green Factor score of 0.8

Stormwater Runoff

  • Single family homes must achieve 100% infiltration. With qualified exemption (e.g. jurisdiction will not allow infiltration on site, Civil Engineer statement to show have achieve maximum possible runoff reduction due to site conditions) the home may achieve 50% reduction
  • Multifamily buildings must achieve minimum 50% runoff reduction Materials

Environmental Attributes 

  • Project must contain a minimum of 20 components that include at least one environmental attribute. Environmental Attributes include:
  • Locally sourced/manufactured within the State of Washington. If used for wood products must still be certified, or harvested under State small forest owner program
  • Building salvage or reclaimed material
  • Recycled Content (highest percentage available for material type)
  • Product certified by a recognized 3rd-party certification. Wood products must meet Built Green’s Tier 1 level.
  • Rapidly Renewable with a harvest cycle 10 years or shorter
  • Product is durable with a minimum 50-year life cycle Additional materials requirements:
  • Project must receive an overall construction waste recycling rate of 90% or better
  • 90% of wood products by board feet must be Tier 1 certified, building salvaged/reclaimed, rapidly renewable, or recycled content

Concrete must be one of the following:

  • Reduce Portland Cement by 25% (GO wording: Mix design to reduce portland cement content to 330 lbs. / cu. yd. or less for 2500 p.s.i. concrete, or to 360 lbs. / cu. yd. or less for 3000 p.s.i. concrete.) OR
  • 25 % flyash or blast furnace slag OR
  • 25% recycled aggregate

Health & Indoor Air Quality

The following products may not be used in the project:

  • No PVC
  • No-added urea formaldehyde products may be used in the interior spaces No exposed galvanized metals
  • No biocides (i.e. zinc, copper)
  • No permanently installed wall-to-wall carpet
  • No fireplaces
  • All paints, adhesives, floor finishes, caulks, and sealants, must be low-toxic based on SCAQMD standards.
  • Any foam insulation must have a Global Warming Potential (GWP) of less than 6. (excludes miscellaneous use for sealing)
  • Continuously running HRV must be tied to all bathrooms and kitchens
  • Any duct openings shall be covered during construction. Thorough cleaning of any ducting shall occur prior to occupancy. Ventilate building continuously for a period of one week after final finishes are applied and prior to occupancy.
  • Follow Energy Star Water Management Checklist guidelines for flashing/waterproofing details to ensure water intrusion is minimized. Test wall system to ensure that waterproofing strategies are functioning properly
  • Minimize moisture issues during construction process (Built Green credit 4-7, all items). Do not hang sheet rock until moisture level in wood has achieved 17% or lower.
  • Air intakes shall be located a minimum of 15’ from exhaust locations and away from automobile parking.
  • For Multifamily projects, capillary breaks shall be provided at any building junctions with concrete.
  • A sealed storage area which is partially heated but sealed from dwelling spaces shall be provided for materials such as paint, cleaners, etc.

Read more about green building certifications.

Topics: Building Green, Certification / LEED, Cost of Ownership, Energy Audits, Energy Recovery & Heat Recovery, Going Green, GREAT GREEN HOMES, Healthy Homes, Home Design & Plans, Photovoltaic / Solar Panels, Radiant Heat, Solar Power, Thermal Envelope, Water Saving Devices, WaterSense

Companies: Zehnder America

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