House Description:

Size: 3,800 s.f.
Location: Dallas, Texas
Construction cost: U.S. $171 per s.f.                                               

Background:

The builder decided to construct this Zero Energy Home, along with partners in the Department of Energy's Building America program, to demonstrate what can be done in energy-efficient home construction.  The goal was to build a house that is comfortable to live in, while architecturally pleasing, and without a single utility bill.

The Challenge:

To achieve true zero energy consumption, state-of-the-art energy efficiency and green building practices had to be used.  Icynene^® soft foam insulation and air barrier material was the natural choice for insulation.  It was installed in all exterior framed walls, and a number of interior framed walls for sound dampening.  A key feature of the house is the conditioned attic assembly where Icynene^® was applied up to the underside of the roof system – this keeps living space temperatures low in the hot Texas climate while greatly reducing cooling loads and energy requirements. 
  
Results:

According to the EVHA judges, it's not only a “truly beautiful home,” but it's a “world-class project.”  The judges were impressed by the home's outstanding energy performance and its exemplary use of systems engineering in the HVAC system, building envelope, and renewable energy production.  This house will net true zero energy consumption annually.   

Energy Features:

Framed exterior wall insulation (and interior framed walls where soundproofing was required): Icynene^® spray foam insulation 
Ceiling Insulation: Icynene^® spray foam insulation at roof line
Exterior wall (and roof) construction: Insulating concrete forms
Windows: Double pane, low-e, gas filled, tinted; U-0.38, SHGC 0.29
HVAC: Hydronic heating; 17 SEER chilled water air conditioning system; fresh-air intake to blower with timer control
Ducts: 100% in conditioned space; sealed with mastic
Water heating: 64 s.f. flat plate collector with sealed combustion tankless gas water heater backup.
Lighting: 90% fluorescent
Appliances: ENERGY STAR labeled refrigerator, washer, and dishwasher.  Blow door test: 0.11 ACH50
HERS rating: 94.5

Innovative features: Metal roofing with infrared reflective paint on vented cavity; 8kW photovoltaic system; low-flow faucets and showerheads; re-circulate cooled water back to the water heater; passive solar features; passive solar features; rainwater collection system; chilled water cooling.