4 Green Strategies from The New American Home

The 2021 New American Home (TNAH) and the New American Remodel (TNAR) showcase the beauty, comfort and efficiency of high-performance building. Both represent the high end of what can be realized through high-performance design and construction but can also provide a practical playbook for all building professionals in building efficient, comfortable and durable homes.

Regardless of the market you build in — custom vs. production, climate, square footage, price point, etc. — you can apply several takeaways from the building science used in these show homes to add value and market a high-performance product.

"Building green does not need to be more difficult or extremely costly," said Drew Smith, NGBS Green Master Verifier of Two Trails, Inc. who oversaw the NGBS Green Emerald Level certification for both homes.

"Finding what makes sense for you and your clients is the best way to deliver a high-performance certified project." Here are four high-performance strategies from the 2021 TNAH and TNAR projects that can be applied to your homes.

1. Tight Thermal Envelope: A tight thermal envelope minimizes the transfer of heat or cold across the exterior walls, which translates to lower utility bills and greater comfort.
   • Unvented and air sealed attic
   • Insulation: mix of types, depending on the application and location
     • Attic: TNAH used open-cell spray foam
     • Exterior concrete masonry unit (CMU) walls: TNAH used injected core-fill foam/reflective insulation
   • Windows: low-e coating to limit solar heat gain, argon gas filled to optimize air tightness

2. Indoor Air Quality (IAQ) and Comfort
   • Balanced Ventilation: "Build tight, ventilate right" is a mantra of high-performance building. Fresh air exchange is critical to optimal indoor air quality; proper ventilation improves comfort.
     • Whole-building mechanical ventilation with the ability to maintain relative humidity
     • "Boost" ability to increase fresh air intake when needed (e.g., dinner party)
     • Bath fans and kitchen range hood
   • Filtration: MERV 13 space conditioning air filters
   • Materials Selection
     • Low/no volatile organic compounds (VOCs) in paints, adhesives and sealants
     • Healthy, eco-friendly finishes (flooring, kitchen cabinets, etc.)

3. Above-Code Energy Efficiency: "Energy consumption of new houses can be reduced by as much as 40% with little or no impact on the cost of construction." (TNAH Final Performance Report)
   • Tight envelope (see above)
   • Right-sized HVAC-R systems
   • 100% LED lighting (interior and exterior)
   • ENERGY STAR appliances
   • Smart home tech for climate and lighting control

4. Above-Code Water Efficiency: Improvement of about 50% over baseline can be achieved through fixture choice, plumbing layout design, landscape design and smart (or no) irrigation.
   • EPA WaterSense®-labeled plumbing fixtures
   • Tankless water heaters with insulated hot water lines
   • On-demand hot water recirculating pumps
   • Indigenous landscaping with a minimum of turf grass
   • Irrigation: micro-spray, driplines and programmable controllers

Learn more about the high-performance practices and products used at tnah.com and tnarh.com.

To stay current on the high-performance residential building sector, with tips on water efficiency, energy efficiency, indoor air quality, and other building science strategies, follow NAHB’s Sustainability and Green Building team on Twitter.