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Emerald Star Home is Net-Positive Energy in Seattle, WA

Case Study by Chris van Daalen, Principal Investigator
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Emerald Star Home is Net-Positive Energy in Seattle, WA
Photo by Tucker English
Energy
Plumbing Systems
Net-Zero Energy
Rainwater Harvesting for Indoor Use
City of Seattle, WA
2767603125
John Siu, Building Official, Dept. of Construction and Inspections
Residential
2218
Caron Associates
Dwell Development
Evergreen Certified
Built Green Emerald Star US Department of Energy – Zero Energy Ready Home
Aug 5, 2015

Abstract

In the heart of Seattle’s Ballard neighborhood, this home offers an iconic example of an advanced high-performance home.  It was the first project in Seattle, and the first speculative home, to achieve Built Green’s new Emerald Star rating, and has won a raft of awards and other recognition. The Emerald Star home uses design, innovative materials and technology to achieve net-positive energy, 70% reduction in water use and 90% reclaimed and/or FSC-Certified wood.

Permitting Process

The home was permitted prescriptively using Washington’s progressive building, plumbing and energy codes, while taking advantage of the City of Seattle’s Priority Green expedited permitting incentive to save four weeks in permitting time. The home’s advanced yet simple rectangular design uses 12” thick double-stud wall, insulated slab and foundation, and advanced air sealing to achieve a blower door test result of at 1.17 ACH 50, which is 77% better than state energy code requirements for air leakage.  They used Chapter 17 of Washington’s Uniform Plumbing Code to design a rainwater collection system, plumbed for the home’s toilets, hose bibs, and cold water to the laundry. They used Sanden’s innovative heat pump water heater technology (see related case studies) for both radiant space-heating and domestic hot water; and a heat-recovery ventilator to provide fresh healthy indoor air; and manage energy use with intelligent control systems.

Code RequirementCompliance Path
2012 Washington State Energy Code required 5.0 air changes per hour or better, plus 1.5 additional energy credits for energy efficient features Using an airtight, super-insulated building envelope, and other ultra-energy efficient features, the home exceeds Washington State Energy code requirements by 77% and was approved under prescriptive building code requirements.
Washington’s Uniform Plumbing Code sets requirements for Rainwater Harvesting for indoor use. Project followed prescriptive requirements in UPC Section 17.

Project Description

The ultra-efficient design of the Ballard Emerald Star home was inspired by the Passive House design standard, with an airtight, super-insulated building envelope.  Other ultra-energy efficient features include:

  • European triple-paned, argon-gas filled, solid wood-framed windows, with low emissivity coatings, whole-window insulating average value of U=0.14, and an SHGC=0.50.
  • The home has in-floor radiant heating, powered by a 450% efficient CO2 heat pump water heater, feeding an 83-gallon storage tank for both space and to water heating.
  • The heat pump uses a CO2 refrigerant with a very low global warming potential compared to other refrigerants.
  • A heat recovery ventilator (HRV) provides whole-house ventilation, bringing in fresh air and recovering heat from the exhaust air; while continuously mixing air for comfort throughout the house.
  • Rainwater Cistern supplies all non-potable uses
    Efficient ENERGY STAR qualified appliances (refrigerator, dishwasher, and clothes washer) and 100% LED lighting keep electrical loads to a minimum
  • An 8.1-kW solar photovoltaic array on the roof provides enough electricity to meet the home’s annual electric needs, and supports an electric car charging station.
  • The home is equipped with an internet-connected home energy management system, Kirio, which adapts to occupant behavior by tracking and managing electric usage and PV production.

Ultra-efficient water conservation strategies save both water and energy, and help meet the Emerald Star requirement of 70% reduction in water use over an average Washington home:

  • WaterSense low-flow plumbing fixtures throughout the home
  • Insulated structured plumbing loop circulates and delivers hot water to fixtures instantly, providing convenience with efficiency
  • A 420-gallon storage cistern harvests rainwater from the roof which is filtered twice and used in the clothes washer (cold water side only), toilets, and outdoor hose bibs.

The home meets all of the criteria of the U.S. Environmental Protection Agency’s Indoor airPLUS program including the use of all no-VOC finishes and site water management practices.

Seattle’s Priority Green permitting incentive provides a guarantee of 4 weeks initial plan review on complex projects designed to meet Built Green 4-star+, Passive House certification, etc. (See related Policy Profile:  Priority Green Permitting at City of Seattle – forthcoming).  This successful incentive has seen a strong response as shown by both a surge of single family homes certified Built Green up from 33% in 2014 to 58% of the market in 2016.  There has also been a shift in Built Green star-levels.  Though 3-Star is the easiest Built Green certification level, a year after Priority Green enrollments picked up, Built Green saw a shift to 4-Star as its most popular level.

Additional Resources:

The Greenest Home on the Block:  1-Year Energy Usage Report The Greenest Home on the Block:  Video about the project
Housing Innovation Award Zero Energy Home Case Study:  Dwell Emerald Star, by US Department of Energy Built Green Emerald Star Level Requirements Fact Sheet
Seattle Priority Green expedited permitting program for certified homes and buildings

Motivations

The Ballard Emerald Star home exemplifies Dwell Development’s mission to “always lead, always challenge, and always strive to do more.” They exclusively build 5-Star or Emerald Star Built Green homes and this home was Dwell Development’s 100th certified home. They are leading the charge both as an industry exemplar, and also through their collaboration with The Master Builders Association of King and Snohomish Counties and its Built Green program. With this project, Dwell helped test the Emerald Star Certification, in the process becoming the first Seattle project ever to achieve this extremely challenging standard. 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.

Leah Missik of the Built Green Program said “Innovative projects like this one demonstrate that deep green building has the potential to become more mainstream. Built Green aims to provide builders with the tools to get into green building and then further their efforts to increasingly greener projects. Dwell Development’s work is an example of a builder who already does fantastic work challenging themselves to be ever more sustainable, setting a model for the industry.”

Design / Build Process

Company owner Anthony Maschmedt is quoted in the DOE Case Study as saying “Our team’s involvement from pre-design through approved building permits is where we attribute our success. The details are the difference. Pre-construction meetings with the City (Seattle) and all our subs set the tone and expectations.”  The team includes not only in-house project managers and specifiers, but key subcontractors that must work together in an integrated way to achieve a precision outcome. High-performance building requires and smart and strategic design, so they partnered with local firm, Caron Architects to deliver a top-quality product.  For renewable energy, they brought in an expert solar installer Puget Sound Solar, to deploy 8.1kW of photovoltaic panels on the roof enough to power the house. Their utility bill consists of $50/year in fees, but no usage charges.

Cost / Benefit

Even with the highest degree of sustainable design, materials and technology, Dwell stays competitive and profitable, on equal or better footing than more traditional builders in the area that build to code minimums. They are a speculative builder, but their projects are almost always sold before they’re finished being built. Their Built Green homes bring a price premium because of the quality sustainable features.  Maschmedt commented in the DOE case study about their return-on-investment for going the extra mile:  “Zero days on the market and selling at the highest price per foot at the time for this neighborhood proved that what we are doing is working…”  This 2,218 sf home sold for $850,000 in August 2015 ($383/sf). “Our goal and mission now is to have every home we build be Net Zero Energy.”  For him, this project was about “knowing and showing to everyone that you can design and build a Net Zero Home and be profitable!”

Awards

2016 U.S. Department of Energy Housing Innovation Awards, Grand Winner
2015 Built Green Awards, Project of the Year
2015 Green Home Builder Awards, Custom Home of the Year
2015 NAHB Best in American Living Awards, Single-Family Specialty Green-Built Home

Project Contacts
Developer: Anthony Maschmedt, Principal Dwell Development (206) 683-7595 Certification Verifier: Tadashi Shiga, Principal Evergreen Certified (206) 491-7111 Approving Official: John Sui, Building Official City of Seattle Dept. of Construction and Inspections (206) 684-8600
Approving Official: Patrick Beaulieu, Inspection Supervisor City of Seattle Dept. of Construction and Inspections
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