Passive Solar Design | TC Legend Homes

Bellingham Gentle Density DADU

by Senna | Jul 18, 2019

TC Legend Homes demolished an existing one-car garage and re-purposed the available space with a cozy, high-performance, 775 square foot, detached accessory dwelling unit (DADU) that includes an attached single-car garage. The RE Store handled the structure demolition to maximize recycling opportunities and minimize waste.

The DADU was designed from the ground up to be net-positive-energy, meaning it will produce more energy on an annual basis than it requires. TC Legend Homes applied the same approach and many of the same building techniques to this DADU as it does to any of its other homes.

Key Features

A simple design to minimize exposed surface area
Orientation and window placement to optimize active and passive solar
Slab on grade with 4” under-slab insulation & Insulated concrete forms
Structural Insulated Panel construction (vice traditional framing) to reduce possibility of thermal bridging
Triple-pane windows
High-efficiency mini-split heat pump for heating & cooling and high-efficiency heat pump for water heating
HEPA High Efficiency Whole House Insulated Filtration System
5.4kw photovoltaic solar system
Energy Star, EPA Indoor airPLUS, and 5-Star Built Green Certified
Home Energy Rating System (HERS) Index is negative 16! (A typical new home has a rating of + 62).

Toomes’ Bellingham Affordable Net-Positive Home

by Senna | Nov 6, 2018

Built by the TC Legend Homes/Powerhouse Designs team. We design and build. With a standard palette of materials & details that have been chosen, tested & refined over many houses, there is no confusion for the crew. The draftsman, engineer, and crew are consistent through all our projects, so everyone has done this system before.

Key Features:

Positive Energy – produces enough electricity to also power an electric car.
Energy Star, EPA Indoor airPLUS, and 5-Star Built Green Certified.
Honorable Mention in the Affordable Category of the 2018 US Department of Energy Housing Innovation Awards.
The home is oriented for both passive & active solar performance by facing south, as a rectangle with the long side (26’) running from east to west. The home is outfitted with an 8.1kw photovoltaic system.
Energy envelope includes structural insulated panels (SIPs). The 6.5″ Neopor R29 SIPs panel walls are locally made in Washington. Designed & engineered to reduce cold bridging by minimizing structural lumber & maximizing use of foam splines to connect panels. Shell is air sealed with triple beads of mastic at all joints and panels additionally taped at all joints. RIM joist insulated with R30 spray-foam at floor systems. Perfect rectangle box adds simplicity to construction & reduces corners & thus cost & air leakage.
4″ Extruded Polystyrene (EPS), a low VOC foam (R20), is used under-slab. The concrete slab-on-grade is exposed and is effectively a free finished-floor and a functioning thermal mass.
The heat recovery ventilator (HRV) is a Zehnder Comfo-air 200 which can scavenge 95% of the heat from the outgoing dirty air. Running through a class 4 filter (merv7/8) at between 29 and 118 cubic feet/ minute (cfm), the unit ventilates the whole house, extracting moist air from bathrooms/utility spaces, bringing fresh air into living spaces.
Energy Star appliances including a Geospring 50-gallon heat pump-powered hot water heater.
Stormwater from the roofs is infiltrated on-site using splash blocks below the gutter downspouts.
Home Energy Rating System (HERS) Index is negative 25! (A typical new home has a rating of + 62.)

Purchase Plans-Set HERE!

Ballard Net-Zero-Energy Home

by Senna | Aug 4, 2015

Owners: Eric Thomas and Alexandra Salmon

Designer: Zero-Energy Plans, LLC (zero-energyplans.com)

Builder: TC Legend Homes (tclegendhomes.com)

Site Address: 612 NW 60th St., Seattle, WA 98107 (Ballard)

SPECS:

1,915 square feet, single-family, 2 stories, 3 bedrooms + work loft, 2 bathrooms, concrete slab foundation, radiant heat floors, Hardie plank siding.

GREEN FEATURES:

Structural Insulated Panel construction, air-to-water heat pump, 6kw solar electric (photovoltaic) system, triple-pane windows, passive solar design, rain garden, stained concrete floors, reclaimed fir floors, recycled fixtures, zero-VOC paint, low-waste engineering, low-energy LED and CFL lighting, capacity for additional solar panels to power an electric car 5,000 miles per year.

Download Case Study

Leavenworth Passive Home

by Senna | Aug 2, 2015

The hallmarks of a Passive House are super-high levels of insulation, a design that takes advantage of passive solar gain, and, as a result, has little need for heating beyond that provided by the sun, warm bodies, and appliances. Passive Houses also come with a list of requirements, like a heat recovery ventilator, a somewhat costly piece of equipment that recoups some of the energy that would normally be lost from circulating fresh air through the house.

Bellingham Power House

by Senna | Jun 23, 2015

Clifton

Nicknamed the PowerHouse, this house 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.

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.

Specs

2,700 square feet,
3 bedrooms, 2 bathrooms
1st floor aging-in-place
Double height living/dining room
Powers itself and two electric cars, for net-zero emissions, over the course of a yearUses 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
Radiant-heat floors
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
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