Bellevue Net Positive Energy Home

by | Jul 20, 2021

TC Legend Homes – Bellevue Net Positive Energy Home

Located on a portion of a subdivided, family property, this 2,614 SqFt Bellevue, WA home is a beautifully built house that helps to foster multigenerational ties and community. With a 5-Star Built Green rating, EPA IndoorAir Plus certification, and a Net Zero Energy certification, this award-winning TC Legend home is an example of the influence and success of the Build Green program. With a specific focus on indoor air quality, this home employs a new ventilation and air filtration system, helping to make it a safe and comfortable environment for its occupants.

Built with passive and active solar needs in mind, the two-storey house faces south. Numerous triple glazed Vinvltek windows on the south side provide passive heating and light within the home. These windows and others throughout the house are coupled with white interior paint to help provide significant daylighting and reduce energy demand from the 100% LED home lighting. The home also employs a 12.87kW photovoltaic system, producing enough power to make the home net positive and power an electric vehicle. With a shell system constructed from 6.5” SIPs walls, 10.25” SIPs roof, 4” foam under the slab-on-grade, ICF form slab-edge stemwalls & U 0.18 average triple pane windows, this house has a tight envelope, helping to reduce energy consumption.

The three-bedroom, two bath house is meant to allow the occupants to age in place with the kitchen, main living space, a bedroom and bathroom, and ADA compliant doorways on the first floor. The state-of-the-art fresh air system includes a Zehnder 350 HRV, Zehnder Comfopost inline heating/ cooling coil, and HEPA air filtration system. This system allows for fresh, filtered air to enter the home throughout the day and to be increased when needed, such as when the kitchen hood fan is drawing smoke out of the kitchen during cooking. This fresh air system keeps the indoor air clean, reducing particulates in the air, even when the outdoor air quality is particularly poor such as during a summer forest fire.

Overall, this home is a comfortable, clean, and net positive building, allowing the homeowners to be happy, healthy, and confident in the knowledge that their home is serving their needs and protecting the environment in the process. The BuiltGreen Certificate of Merit and 5-Star rating this home received help to reinforce this knowledge due to the standard of excellence required of BuiltGreen certified homes.

Built Green highlights:

 SITE & WATER 

  • Long term erosion reduction strategies in place
  • Over 70% of building site left undisturbed with preservation of trees and native vegetation
  • Stormwater infiltration system catches all stormwater from the site and the uphill grandparents house, mitigating flow
  • Approx. 50% of the lot is turf grass 
  • Watersense certified fixtures and low flow fixtures and toilets
  • Rainwater collection ready

ENERGY 

  • Net-Positive Home with a HERS score of -22 and extra power to serve an electric vehicle
  • 12.87 kW roof PV array
  • Substantial envelope insulation lowers heating requirement: R-30 walls, R-49 roof, R-20 under slab, R-24 slab-edge, average U-0.18 windows 
  • Triple-paned Vinyltek Windows with u-values from 0.15-0.22
  • Passive Heating Design strategies utilized 
  • Chiltrix Air-to-Water Heat Pump for heating and domestic hot water with COP of 3.92
  • AeroBarrier air sealing and blower door results of 0.47 ACH50 
  • 100% LED lighting
  • All Energy Star certified appliances 
  • Energy Star certified 
  • DOE Zero-Energy Ready certified 

HEALTH & INDOOR AIR QUALITY 

  • Indoor AirPLUS certified 
  • Solid wood cabinets with Low-VOC finish 
  • All Low-VOC paints, adhesives, and sealants
  • No gas-burning appliances in house
  • HEPA Air Filtration System
  • Zehnder HRV with ComfoPost

MATERIALS EFFICIENCY 

  • Graphite SIPS for exterior walls and ceilings 
  • ICF foundation walls 
  • 85%+ of waste recycled 
  • Locally produced lumber, SIPs, concrete, cabinets, doors, and siding
  • Exterior cedar posts constructed form telephone pole MFG waste
  • Leftover materials moved to next job 
  • Solid wood, domestically grown interior doors and trim 
  • Locally produced Vinlytek windows

Location: Bellevue, WA
Star Level: 5-Star, Net Zero Energy Label
Checklist: Single Family/Townhome New Construction
Verifier: Ecoe Company

Site and Water: 109
Energy Efficiency: 239
Health and Indoor Air Quality: 126
Materials Efficiency: 109
Total Score: 629

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