Lynden Powerhouse

Lynden Powerhouse

Lynden Powerhouse

Lynden Powerhouse is a highly efficient, net-positive home with an additional ADU and stick-framed garage/shop. This home will receive the DOE Zero Energy Ready Home, ENERGY STAR, and EPA Indoor airPLUS certifications, and anticipated Built Green 5-star certification.

Lynden Powerhouse will provide full-time and temporary housing for up to four separate family groups. This level of complexity required a greater attention to climate and ventilation zoning, which necessitated the installation of three separate Fantech Hero 250 HRV units and one extra-large Chiltrix CX50 heat pump. These devices allowed the home to be compartmentalized into three separately conditioned spaces – the main living space downstairs, living space upstairs, and ADU. Breaking up the air spaces ensures that the fresh air circulation can independently adapt to the measured CO2 levels and temperatures of each air volume. Given that hazardous airborne viruses are a normal part of life for the foreseeable future, having three separated air spaces allows those infected to quarantine without infecting others. Further measures to make the home as energy efficient as possible with the best indoor air quality included hydronic radiant floor heating, HRVs with integrated HEPA filtration, all ENERGY STAR rated appliances, LED lighting, triple pane windows, and Aerobarrier air sealing.

One of the owners, who works in the tech industry, used his knowledge to create innovative automation systems for the ventilation and hot water circulation systems using motion detectors and CO2 sensors to minimize wasted energy, water, and time. Each air space has a motion sensor that will stop the HRV unit if no motion is detected for 24hrs to conserve energy. Additional automation uses custom algorithms to vary the HRV air velocity to balance CO2 extraction with ventilation-induced heat energy loss. Motion sensors placed near each plumbing fixture trigger the hot water circulators only when need is anticipated. By the time the person turns on the fixture, hot water is available, minimizing both water, time, and energy waste.

Lynden Powerhouse features a 17.01 kW solar array with six 48v 100AH LFP batteries for backup storage. The system was designed to be oversized, knowing that the combination of PV with storage allows for disaster resiliency and for the house to operate completely off-grid for weeks if needed. It also supports three EV charging ports, two for occupants and one outside for guests. Moreover, having an oversized solar array on an already super-efficient house, means the owner can eliminate the entire energy bill which makes retirement budgeting more predictable and effectively making the cost of living cheaper in the future. By over-sizing the system, the house can fully power the AC units of four less efficient homes in the cul-de-sac, thereby minimizing peak energy loads for the entire block. The reduction in peak-energy loads helps reduce the stress on the grid caused by extreme weather events. And is the key to eliminating petroleum powered peaker plants, thereby reducing CO2 production for the entire street.




  • Overview:

    • 1549sf SFR &  842sf ADU
    • 1123sf unconditioned garage & shop
    • 4 bedroom, 3.5 bath SFR &  1 bedroom, 1 bath ADU
    • Net Zero Energy
    • 1st floor aging-in-place
    • Passive solar heating/cooling design
    • Insulation: R-29 walls & R-59 ceiling
    • Air Sealing: 0.45ACH
    • HERS Index: -24
    • Annual Energy Cost Savings: $3,717
    • Certifications: DOE Zero Energy Ready Home certified, ENERGY STAR certified, EPA Indoor airPLUS certified, anticipated Built Green 5-star certified



    • Ventilation: (3) Fantech Hero 250 with built in HEPA filter. Built-in humidity, temperature, and CO2
    • Heating/Cooling: Chilltrix CX-50; hydronic radiant floor heating downstairs and (3) fan coil units
    • PV: 17.01kW solar array with whole home battery back-up



    • Timber framed entry
    • Metal roof
    • Locally made walnut and maple cabinets
    • Bamboo Floor Score certified flooring
    • Vanair vented interior doors
    • Locally made solid fir front door
    • Silestone and Corian countertops
    • ENERGYSTAR appliances
    • LED lighting
    • WaterSense plumbing fixtures
    • No/Low-VOC finishes
    • Triple pane, Low-E coated, argon-filled vinyl windows
      Samish Solar

      Samish Solar

      Samish Solar

      Sitting on a stunning 5-acre lot nestled into the woods and surrounded by wildflowers and berries, Samish Solar Home is an oasis for a growing family of mountain bikers and nature enthusiasts.

      Along with this home’s solar array making it net-zero, it has an added level of resiliency with its 28,000-gallon rainwater cistern that supplies the house and its fire suppression system with water. The rainwater is filtered through a sediment filter, activated carbon filter, and UV filter to ensure it is fit for domestic use.

      Built using TC Legend’s tried-and-true methods, Samish Solar Home exemplifies what our construction strategies can produce. Just look at these stats!


      • Overview:
        • 2345 sqft heated living space & 234 sqft unheated sunroom
        • 1600 sqft barn with 895 sqft loft
        • 4 bedroom, 3.5 bathroom
        • Net Zero Energy
        • 1st floor aging-in-place
        • Passive solar heating/cooling design
        • Insulation: R-29 walls & R-59 ceiling
        • Air Sealing: 0.27ACH
        • HERS Index: -20
        • Annual Energy Cost Savings: $2432
        • Certifications: DOE Zero Energy Ready Home certified, ENERGY STAR certified, EPA Indoor airPLUS certified, anticipated Built Green 5-star certified
        • Winner of Housing Innovations Award!
      • Mechanical:
        • Ventiliation: Fantech Hero 250 with built in HEPA filter. Built-in humidity, temperature, and CO2
        • Heating/Cooling: Chilltrix CX-34; hydronic radiant floor heating downstairs and a fan coil unit upstairs
        • PV: 10.8kW solar array with Enphase microinverters and battery ready
      • Selections:
        • Timber framed entry
        • Locally made cherry cabinets
        • Certified metal cool roof
        • Greenguard Gold Maple flooring
        • No/Low-VOC finishes
        • Fir doors and trim
        • Triple pane, Low-E coated, argon-filled vinyl windows
      Tree-View House

      Tree-View House

      Sitting nestled in the trees with beautiful green views out of every window, this house really lives up to its name—Tree-View House. Both clients and designer Jake did a superb job ensuring the color of the forest framed the main living spaces through the thoughtfully placed windows and use of neutral-colored finishes, making you really feel at one with the surrounding ecosystem. 

      As a family of 5 with a need for both play and work, Tree-View was designed separating the children’s space from the parent’s space with 3 bedrooms and a wet bar on the lower floor and a master suite plus office on the main living floor. The lower floor suite and wet bar were also designed with dual purpose, as they can be turned into a mother-in-law suite in the future. The front entrance also features a large wooden deck at street level, allowing the main floor to be aging-in-place accessible. Additionally, the deck is a great way for the family to engage with the community and can double as a play area along with the spacious driveway. In total, the house is 2,116 square feet with 4 bedrooms and 3.5 bathrooms. 

      Tree-View is built using our tried-and-true envelope and mechanical systems: 6.5” structural insulated panels (SIPs) walls, 10.25” SIPs roof, 4” R20 foam under the slab, R24 insulated concrete forms (ICF’s), Chilltrix CX34 heatpump with (1) fancoil unit, Fantech HERO 250H HRV with comfopost heat/ cool delivery, Vinyltek triple pane windows and Thermatru front door.

      Obtaining a 0.56 air changes per hour envelop seal, this house exceeds the Passivehaus standard. Tree-View is also expected to receive a 5 Star Built Green rating, along with Department of Energy’s Zero Energy Ready Home rating, Energy Star certification and EPA’s Indoor AirPLUS certification.

      As always, indoor air quality (IAQ) is of utmost importance for TC Legend and our clients and Tree-View is no exception. With a top-quality heat recovery ventilator (HRV), humidity & CO2 sensors, HEPA filters, Awair IAQ monitor, and GreenGuard Gold cork flooring this house was built for clean air. Unfortunately, after about 2 months post-move-in, the surrounding cottonwood trees took an unexpected toll on the house. The massive amount of cottonwood fluff clogged the HRV intake and started cutting off the houses supply of fresh air. Thankfully, the Awair IAQ monitor immediately alerted the clients of the decreasing IAQ, allowing them to reach out to our team who swiftly acted and resolved the issue. Now all parties know to clean the intake regularly during peak cottonwood season! 

      The clients also opted for upgraded Kasa Smart light switches which connect to their phones and can be voice commanded by use of the central smart home device. According to their feedback, this has been a huge success and is incredibly helpful. Thus, further proving this smart home is truly the way of the future! 

      Neos House

      Neos House

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

      Designed as a multi-generational home with one full bathroom & one full bedroom on the 1st floor, if the piano-room & the rec-room were enclosed with walls we’d have a 7-bedroom home. Enough for a substantial family to live together.

      Pointing south, the view looks towards the huge garden.

      The garden spills into the dining area through sliding doors. The folks who commissioned this home are gardeners, with kids, who will be drawn towards the natural world as a way to thrive.

      The weather briefly nips at you as you walk from the front door to the garage under the covered walkway, creating a connection with the day’s weather and the world outside the energy-shell.

      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.

      Despite one design mistake (the mechanicals are in the unheated garage), this house is an exercise in textbook design for cost & energy performance.

      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.

      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.

      All the stormwater from the roof is infiltrated back into the onsite soils via a huge infiltration trench. Additionally, the excavation soils all remained onsite to reduce soils trucking. The clients took responsibility for seeding the exposed construction soils, choosing to plant a complex cover crop in place of the usual grass. The cover crop can be tilled back into the soils to impart nitrogen & other nutrients when a new planting regime is decided upon.

      The house in a garden is a traditional family way of life and TC is proud to have built a modern, dense & flexible version of this ideal, updated to make all its own power to address the demands of the climate-change world.



      This 2,540 square-foot clerestory (one-and-a-half story) family house has an integrated, differently heat-zoned 1,040-square-foot garage and woodshop sitting within the SIPs shell. It was built in 2020 in western Washington.

      A rigorous passive-solar window design uses the majority south-facing glazing for wintertime heating, shaded in summer by a shallow south porch and accurate south clerestory overhang. Multi-direction daylight penetrates and reflects deep into the connected main living space and second-floor balcony via the high second-floor clerestory glazing. 

      Multiple cutting-edge HVAC and home-automation systems integrate to deliver low-cost air-to-water heat pump-based central heating, cooling, and fresh-air delivery, triggered via automatic carbon-dioxide and humidity sensors. Alexa-driven automated lighting and blinds are installed, a home-automation system that will expand in its capabilities as more options become available.

      The clients’ requirement for a spacious first-floor master suite led us to design a smaller second floor in relation to the first. The clerestory design accommodates this layout by producing a daylight-rich one-and-a-half-story house.


      • U.S. Department of Energy Net-Zero certified
      • Chilltrix CX34 air-to-water heat pump
      • Zehnder 550Q heat recovery ventilator (HRV), with in-line fan coil from Chilltrix
      • Development dedicated 1 acre of pastureland to a perpetual conservation easement, ensuring growth of native species
      • 12.4 kW of solar panels installed
      • 6.5” R-29 SIPs walls
      • 12.25” R-59 SIPs roof
      • 4” R-20 foam under 4” concrete slab-on-grade for excellent thermal mass
      • 5.5” foam (total) R-23.8 insulated concrete forms (ICF) perimeter stem-walls
      • Vinylek Boreal series triple-pane windows (U values between 0.14 and 0.16)
      • 1:1.6 aspect ratio floor plan, with long side facing south
      • Minimal east and west glazing