Positive Energy SIP House Bellevue WA

Location: Bellevue, WA

Project Information

Project Type: Residential, > 3,000 sq. ft.
Manufacturer: Premier Building Systems
Builder: TC Legend Homes
Design Professional: TC Legend Homes
Year Built: 2021


High Performance: Yes
HERS/EUI Index Score: -22
ACH50 - Blower Test Results: 0.47
CO2 lbs./sq.ft./year:

Awards/Certifications: Building Excellence Awards, DOE Zero Energy Ready Home, EPA Indoor AirPLUS, Nat'l Green Building Standard

BEA: 2022 Homes Over 3K Sq. Ft. High Performance Runner Up

Building use:
The Neos house is a 4 bedroom family house. 2614 square feet. Completed in spring 2021.

How did SIP construction help you get this job?
We were able to train a subcontractor to install SIPS to optimize our local staff & resources. The SIPs installation was subcontracted because this is a Bellevue job & the TC crew have northern families & want to be home at night if possible. Issac taught a Peruvian framing crew how to sling the SIPs and the job ran fast & smoothly using advanced SIPs details required by the Bellevue jurisdiction.

SIP wall thickness: R-30: 6.5" graphite SIP panel (R-29), house wrap, fiber cement.
SIP roof thickness: SIP gable roof: 10.25" R-49 graphite-EPS SIPs, asphalt composite

Benefits of using SIPs on this project. Did SIPs help save time, labor, construction costs, or energy?
It helped us to save on labor, time and construction costs. The client did a stellar job of following design advice & the crew lovingly built the house, sealing the envelope to 0.6 air changes per hour, Passivehaus standard. The result is an economical house that has won a Department of Energy Grand Prize, attained 5-star Build Green certification and is certified Net Zero.

Innovative design elements or structural engineering involved:
The envelope & mechanical systems are all drawn from the 2020 TC system: 6.5” walls, 10.25” SIP roof, 4” R20 foam under the slab, R24 ICF’s, Chilltrix CX34 heatpump with (1) fancoil upstairs, Zehnder 350 HRV with comfopost heat/ cool delivery. Vinyltek triple pane windows & Thermatru front door.

Certifications the project received:
This house won a Department of Energy Grand Prize, attained 5-star Build Green certification and is certified Net Zero.
HERS Index: without PV: 35; with PV: -22
Blower door test results:  0.47 ACH50, all SIP joints taped and sealed with double-bead mastic tape. Whole-house aerosol sealant

Air-to-water heat pump with 50% central air handler, 50% radiant, 3.92 COP, AC variable speed compressor, 23.02 EER.

Addditional energy-saving materials used in the building envelope:
The triple-pane windows on the south side have a U value of 0.15 and a SHGC (solar heat gain coefficient) of 0.46.

Additional energy-efficient products or design features:
The home is designed to take advantage of passive solar heating and shading with a floorplan that is longer in the east-west direction and puts a majority of the windows on the south sides of the house. In the winter, sunshine can pour in the well-glazed south side of the house and heat up the floors like a thermal battery. In the summer, the 2.5-foot roof overhang upstairs and full-length 3.5 foot covered porch downstairs shield windows from direct summer sun. East-, west-, and north-facing sides of the home have fewer windows.

Solar Panels installed:
12.87 kW, rooftop panels.

Additional sustainable materials or design features:
EV charging, accessible floorplan, doorways. No-VOC paint, cabinets.

Additional comments:
Overall, the homeowners are amazed. “We are loving our new home. It’s still almost unbelievable to us how air-tight it is in here. It’s so quiet inside, we barely hear any exterior sounds…. We definitely underestimated the amount of light and heat that would come in, both on the west side alone and in the home overall. It is so bright in here. I love it!” said one of the owners.

DOE link to this project: Positive Energy SIP House Bellevue WA

To explore other Zero Energy Ready Homes, visit the Department of Energy’s Tour of Zero page.


Affiliated Members

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