The Murray's

The Murray’s are building a new, naturally-landscaped, single-family house in Portland.  This one-story, three bedroom house will have 3,000 square feet of living space.

Orientation and Envelope:
The orientation of the house will take advantage of the sun, both actively and passively.  Rooms that will receive the most occupancy are lined up along the five-degrees-west-of-solar south side.  A five-foot roof overhang will allow solar gain to the interior walls of these south-facing rooms in the winter, while preventing direct sun even on the window sills in the summer. 

The windows will be fiberglass-framed windows, triple glazed to the north, east, and west and double glazed to the south for passive solar gain in the winter, plus low-e and argon where appropriate.

• Walls: Continuous R-25 walls will be achieved through 6” Insulated Concrete Forms (ICF)
• Ceiling/Roof:  Total R-Value 40, achieved through 2” closed cell spray foam (R-14), plus 7” open-cell spray foam (R-26)
• Slab On-Grade Insulation:  R-20 rigid foam board around perimeter and R-10 rigid foam board for remainder of slab

Heating, Cooling, and Hot Water:
Radiant floor heating will be supplied by a three ton geothermal system and a solar thermal system.  No air conditioning will be installed based on extreme detail and attention paid to the envelope.

Ventilation:
Whole house balanced ventilation, entirely in conditioned space, will be provided by a rotary energy recovery ventilation (ERV) system that will correct for an increase in home occupancy, use of bathroom, kitchen hood, or laundry room fans, and severe outside freezing. 

Electrical:
All appliances and lighting fixtures will meet ENERGY STAR requirements.

Renewables:
A solar thermal system will be PEX-tubing in aluminum heat-transfer plates mounted on spacers above the sheathing of the south-facing roof.  Raised above this PEX will be a standing-seam metal roof to which thin-film photovoltaics (PV) will be adhered.  By combining solar thermal with solar electric in this manner, the sun’s heat will be drawn away from the PV, keeping it more efficient.  This low temperature solar heat will, in conjunction with geothermal heat, provide for domestic hot water and in-slab hydronic radiant. 

Resources Sustainability Features:
Where possible, a material will be used for multiple purposes during the construction process:

• Same lumber will be used for footing forms, ICF bracing, window/door bucks, and internal wall framing
• Same I-joists for vertical ICF bracing and then for attic joists
• 30 trees cut at house site sawn into lumber for interior woodwork