La Pedrera



As an architect herself, the homeowner was excited by the chance to design build a net-positive energy home for her and her family while relocating to the San Juan Islands. Their new home, situated on a rocky outcropping above the Puget Sound, was dub bed La Pedrera, “the quarry”.

Through careful collaboration with our experienced high-performance team at Bellingham Bay Builders and energy modeler and residential certifier Elizabeth Coe of Ecoe Company, the home successfully met the net-positive energy goal. Key to this success was starting with an integrated design team including the owner, the architect, the energy modeler, and the builder.

This home design met not only its energy goals but many other equally important qualities, creating a space that is durable as well as low maintenance, beautiful and inspiring, comfortable year round, and built within a manageable budget.

To reach these rigorous goals we employed many tactics including a continuous exterior layer of mineral wool insulation, a ductless mini-split heating/cooling system, and a ducted heat-pump water heater. Perhaps most importantly (but somewhat nerdy), is the very careful air sealing of the building envelope which provides big benefits in energy efficiency, durability, indoor air quality, and comfort.

To nerd-out a little further, our carpenters took great care to seal every building penetration during the framing stage and then test the airseal using a blower door. This home’s blower door tested out with an excellent result of 0.78 air changes/hour at 50 pascals. These and many other building strategies employed on the project have culminated in a home that truly met expectations.

Net-zero and net-positive energy homes are becoming more and more common. In the building industry, we are starting to adopt patterns in practices and equipment that lend themselves more easily to these great high-performance homes. We applaud as our industry and society work toward lowering our global climate footprint.



Oriented for passive solar gain, solar panels, and durable building envelope with rain screen + large overhangs


Located in a small island association with excellent access to parks, trails, waterfront, and other natural amenities


Designed to minimize clearing on the site and maintaining the many mature trees with the area immediately around the house getting planted with natives and other drought tolerant plants

Water Efficiency

Rainwater collection, low-flow fixtures, dual-flush toilets

Energy & Atmosphere

Net-positive energy with a HERS score of -8; DOE ZERH certified, DOE HIA national contestant, and Energystar certified. Features include: large solar panel array, Daikin ductless mini-split heat pump, heat-pump water heater, LED lighting, induction cooktop, heat-pump clothes dryer, super-insulated envelope (including full thermal break for foundation), less than 0.8 ACH @ 50pa, charging station for EV’s in garage

Materials & Resources

Construction waste recycling, salvaged fir timbers, use of recyclable materials (i.e. metal roofing), FSC-certified wood decking

Indoor Air Quality

Indoor AirPLUS certified, Lifebreath HRV, tight building envelope with controlled air exchange, no-VOC paints & finishes, durable floors in wet rooms, rain-screen siding detail, water-vapor managed membrane

Certifications & Education

DOE Zero Energy Ready Home, EnergyStar, Indoor AirPLUS

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