Larson

Larson

This 2,020 square-foot two-story, five-bedroom family house was built in rural King County. It has an additional 280 square-foot integrated single-car garage within the SIPs shell. The garage can be re-purposed into a flex space, such as a kids’ TV room, playroom, workshop, etc. The home was built in 2018 in western Washington.

The major challenge with this undeveloped site was to dig the potable water line 1,000 feet through a boulder field. The client miraculously located the well stub within the forest, and the TC Legend team dodged and weaved the waterline through.

Additionally, we carved the driveway 500’ through the second-growth forest, located the house for optimum solar exposure, and laid the power line in the middle of the driveway, with septic adjacent under what will likely become a forest lawn. A truly stunning site with stag deer, bear, cougars, and more.

The wrap-around porch with concrete walkway mediates between the inside and outside, with a front mudroom to contain kids’ messes and offer an airlock to prevent large temperature drops when the front door is opened in winter.

The house was prevented from becoming overly large and expensive by sizing the kids’ bedrooms at kids’ scale: on the small side of things. However, the vaulted SIPs ceiling at the second floor, which is a standard feature of SIPs construction, presents a very spacious overhead feel. Additionally, multiple windows in many bedrooms ensures that the kids rooms don’t feel boxy.

Specifications

  • U.S. Department of Energy Net-Zero certified
  • Fujistu 18RLXFG heat pump with multiple fan coil heads
  • 12.4 kW of solar panels installed
  • 6.5” R-29 SIPs walls
  • 10.25” R49 SIPs roof
  • 4” R-20 foam under 4” concrete slab-on-grade for thermal mass
  • 5.5” foam (total) R-23.8 insulated concrete forms perimeter stem walls
  • Euroline triple-pane windows (U values from 0.14 to 0.18)
  • 1:1.6 aspect ratio floor plan, with long side facing south
  • Minimal east and west glazing

 

Chappell

Chappell

This 1,950 square-foot, two-story, 3-bedroom family house was completed in Seattle in 2018. It has a two-wall carport adjacent to the back door.

The project presented a challenging permit process for the TC Legend office and a complex dig: The undeveloped lot was located atop a known landslide area, requiring deep pin piles and extensive geotech involvement. A heavily protected 6-foot-diameter seqouia tree stands beside the only site entrance and was successfully cared for during the extensive dig, with drain lines threaded through the roots, dug by hand.

With the main hilltop vista facing west, the challenge was to have the house embrace the view without overheating in the afternoon sun. Retaining the deciduous western tree cover was essential, as was ordering the western windows with low solar-gain coatings.

The storm-water system was not allowed to point-discharge onto the steep slope. The extensive use of permeable pavement ensured the trees and shrubs remain watered, stabilizing the slide-prone slopes.

Specifications

  • U.S. Department of Energy Net-Zero certified
  • Chilltrix CX34 air-to-water heat pump
  • Zehnder 350 HRV
  • 10.8 kW of solar panels installed
  • 6.5” R-29 SIPs walls
  • 10.25” R-49 SIPs roof
  • 4” R-20 foam under 4” concrete slab-on-grade for thermal mass
  • 5.5” foam (total) R-23.8 insulated concrete forms perimeter stem-walls
  • Euroclime triple-pane windows (U values between 0.14 and 0.18)
  • 100% rainwater-permeable driveways and walks
Bellingham Power House

Bellingham Power House

There’s nothing we love more than building overachieving homes. This remarkable home not only produces enough solar electricity to meet its own energy needs, but it produces surplus power to charge two electric cars.

Nicknamed the Power House, it is the first of its kind in Whatcom County. The home sends power to the city’s electrical grid when the sun is out and draws it during the night or on cloudy days. (Contrary to popular belief, the Pacific Northwest is an excellent place for solar). Averaged over the entire year, the panels will produce more power than the house uses, with enough of a surplus to power two electric cars through on-site charging stations.

The house qualifies for a one-time federal tax credit of approximately $10,500 and Washington State solar production credits of approximately $5,000 a year until 2020.

Perhaps more remarkable than the home’s efficiency is its modest price tag. Shared by two couples and three children, the 2,700-square-foot custom home cost under $150 per square foot to build, significantly less than most other residential construction projects in Bellingham. 

With its airtight shell, structural insulated panel (SIP) construction, numerous south-facing windows and passive solar design, highly efficient heat pump, solar hot water, and a solar PV array using Bellingham-built ITEK modules, this one-of-a-kind house has no electrical bills (other than the monthly service charge for this  grid-tied system) and costs nothing to heat. No oil, natural gas, or other fuels are used. 

This home shows that cutting-edge energy efficiency technology can actually be made affordable by eliminating entire categories of expenses, like heating and gasoline bills. And if one house can be shared by two families, expenses are decreased for both.

Specs

2,700 square feet, co-housing duplex for 2 families, 2 stories, 3 bedrooms, 3 bathrooms, 3 multi-purpose rooms: loft, rec room and sunroom, semi-covered deck, covered parking, acid-stained concrete slab foundation, radiant-heat floors, exposed beams, Hardie plank & milled cedar siding, metal roof, solar hot water, 9.9 kW solar array, 2 electric car charging stations.  

  • Powers itself and two electric cars, for net-zero emissions, over the course of a year

  • Uses a 9.9kW photovoltaic system (half power goes to the house, other half powers two cars)

  • Envelope includes structural insulated panels, insulated concrete forms, and 4” foam under slab

  • Heat and hot water provided by a solar hot water collector with an air-to-water heat pump backup

  • South-facing high solar gain triple-pane windows and solar absorbing concrete floors

  • Utilizes the most energy-efficient appliances and lighting available on a budget

  • Collects rainwater for all outdoor water usage and utilizes low-flow fixtures indoors

  • Provides housing for four adults and three kids with enough garden space to feed both families

  • Budget under $150/SF includes all development costs except land (built on an infill lot in the city)

  • Northwest Energy Efficiency Alliance is monitoring home for US Department of Energy pilot program

  • Fresh air provided by heat recovery ventilator and earth tube combo system

  • HERS rating is -15

Affordable Net-Zero-Energy Home

Affordable Net-Zero-Energy Home

Net-zero on a budget: A 1,055-square-foot home in Bellingham, WA that, features high-efficiency appliances, a balcony, a greenhouse, a patio, a loft, tongue-and-groove pine ceilings, and solar photovoltaic panels—all for $151,908 or $144 per square foot (not counting the land). A 3.2-kW PV system is all it takes to power the home, thanks to a highly insulated building envelope and high-performance equipment.

This custom net-zero-energy home, built for a Bellingham couple nearing retirement, won the grand prize in the Affordable category at the U.S. Department of Energy’s Housing Innovation Awards.  

The house is small but spacious feeling. It utilizes passive solar heat gain during the cold months, and is net-zero. (The photovoltaic energy annually produced equals all the energy annually consumed, including gas.) Best of all, it is very affordable. This home, a collaborative design effort between TC Legend Homes and the homeowners, was intended to demonstrate an alternative to ultra-expensive, extravagant “green” homes commonly seen. A net-zero home which is truly affordable for the average person perhaps has the greatest potential for conserving our planet’s resources.

The footprint is only 630 square feet, but the added loft brings that up to  about 1,000 square feet of living space. The foundation is constructed from insulated concrete forms (ICFs) with a concrete slab-on-grade floor. A waterproof concrete with premixed dye was used. Four inches of rigid foam under the slab provides insulation from the ground. This floor serves as a thermal mass during sunny winter days, absorbing and storing the sun’s heat as it shines through the south-facing windows and doors.

The walls and roof are assembled from structurally insulated panels (SIPs). These factory-cut custom panels feature continuous foam insulation sandwiched between two OSB boards. This eliminates the thermal bridging which causes cold spots where studs are located when conventional framing practices are employed. The walls were made from 6″ thick SIPs, and the roof was made from 10″ thick SIPs. The house is oriented with the front facing south, both to maximize passive solar gain and to present a south-angled roof on which to mount the solar panels.

All of the windows are triple-paned low-E glass. The porch roof angle allows the sun to enter the house in the winter but blocks the higher-angled sun during the summer months. There is also a green house off of the kitchen portion of the porch.

The primary heat source during non-sunny periods is an electric “mini-split” heat pump. These remarkably efficient units will keep a home of this size comfortably warm during the winter months for a fraction of the typical heating costs of the average house. The monthly total electric bills for this electrically heated house range from $9 to $30.

The head unit of the heat pump is positioned so that warm air is directed toward the concrete floor, storing the heat and warming the floor.

Fresh air exchange can be a challenge in tightly sealed homes such as this. Many modern homes solve this with expensive and power-consumptive heat exchange ventilation systems. As an alternative, this home employs a very simple, but effective, solution. Incoming air passes through “earth tubes,” which pre-warm the air in the winter and pre-cool it in the summer.

The appliances are smaller in size and very efficient. The slightly smaller appliances allow room for more counter space. The counters are stained concrete, molded on site, a considerable cost savings. The hot water system is a tankless, on demand unit.

Perhaps the most unique feature of this home is the feeling the internal space instills. There are only two internal doors. They are on the bathroom and a small downstairs bedroom. The rest is one open living space, but wherever one stands it feels like a separate room, and it always feels spacious. The layout was tailored to meet the needs of two people without children, but with only minor changes it could comfortably be converted to two bedrooms and two bathrooms.

An Award-Winning Home

The U.S. Department of Energy, which awarded TC Legend a Housing Innovation Award for this home, also created an excellent case study. Here are some highlights:

Energy-Efficient Plan Designed by TC Legend Homes

The Bellingham home achieves this performance with a simple plan designed by Clifton to maximize efficiency and minimize cost, with an open two-story layout including a small 630-ft2 footprint and a 400-ft2 loft. The home was placed on the lot to maximize passive solar heat gain and avoid shading the PV system, while retaining existing trees.

Attention to Detail Gets Results

Attention to detail helps Clifton achieve a very airtight envelope that shows air leakage of only 0.67 air changes per hour at 50 Pascals pressure difference (ACH 50) when tested with a blower door. . . . “Normally the insulation contractors spend about 2 hours air sealing. We spend 20 hours or more on a house, depending on the size of the house. It’s a line item in the budget. We may spend $2,000 on air sealing because we caulk everything,” said Clifton.

A Home That Practically Heats Itself

One high-efficiency ductless mini-split heat pump provides [heat]. . . . Despite the high efficiency of the unit, it rarely runs according to the homeowners, because the building shell is so well insulated.

Designed to Power a House and Car with Solar

The home’s standing seam metal roof simplified installation of the 3.2-kW grid-tied PV system. The homeowners Kristina and Mike Heintz were so interested in the installation of the solar panels that Kristina took on the task of locating the best solar value possible and ordering the panels. She has since joined TC Legend’s staff to handle solar panel purchases for other clients. . . .Clifton noted that while the 3.2-kW system meets all the home’s power needs, there is room on the roof to add enough PV to power an electric car as well.

Key Features

  • Walls: 6 in. SIPs R-26; pre-finished fiber cement siding; house wrap

  • Roof: 10 in. SIPs R-42; metal standing seam roof

  • Foundation: ICF foundation R-28; R-20 rigid high-density EPS foam board under slab

  • Windows: Triple-paned vinyl-frame, U=0.20, SHGC=0.45

  • Air Sealing: 0.67 ACH 50

  • Ventilation: 30 cfm, 2.7-Watt continuous exhaust fan in bathroom balanced by earth tube that brings in filtered, tempered outside air passively via 100-ft, 6-inch-diameter pipe buried 2 feet below ground inside foundation footing. Spot ventilation fans in kitchen and utility closet

  • HVAC: One ductless heat pump 12 HSPF, 21.5 SEER

  • Hot Water: Instant tankless condensing gas-fired water heater; 0.96 EF

  • Lighting: 100% LED for all fixed lights, 100% CFL for lamps

  • Appliances: High-efficiency electric washer-dryer combo

  • Solar: 3.2-kW PV

  • Water Conservation: Low-flow faucets, shower head

  • Other Low- to no-VOC glues, adhesives, and paints; water-based sealer on concrete floors

Montlake Modern

Montlake Modern

After more than two years of looking at dozens of houses, putting down multiple offers on several properties, and just not being able to find exactly what they wanted, Relja and Yoojin decided to build their own house. With two architects in the family, it probably wasn’t very surprising.

The modern, positive-energy home they designed meets all its own energy needs while also powering an electric car. 

Both Relja and Yoojin work in the technology sector, and building their home with the most advanced materials was important to them. However, after receiving bids from other builders, they weren’t sure their dream home would be within their price range. After teaming up with TC Legend Homes, they found that building with advanced materials, such as structural insulated panels (SIPs) and insulated concrete forms (ICFs), could actually fit their budget.

In keeping with the high-tech concept, the house includes the latest in home automation to further reduce energy requirements. Heating, cooling, and the LED lights are all controllable through wifi. Even the master shower has a feature that prevents the water from turning on until the desired temperature is reached. The owners are looking forward to writing their own apps to help automate the house.

Features

  • Fresh air system utilizing HEPA filtration

  • Storm water managed with pervious concrete

  • Triple-pane windows

  • Zoned radiant heat powered by an electric heat pump

  • All-electric heat and appliances, including an induction cooktop

  • Car charging station in the garage

Press

Energy.gov
DOE Tour of Zero: Montlake Modern by TC Legend Homes

Green Building Advisor
Modern Dream Home is Energy-Positive

Curbed.com
Modern Marvels: Net-Zero Montlake Modern House Keeps It in the Family

Family photos courtesy of the homeowners and Katie Blanch Photography.