EPS New Construction

How to exceed Washington’s new energy code

The new 2018 Washington State Energy Code (WSEC) went into effect on February 1, 2021. Homes built in Washington must now obtain a minimum number of energy credits to meet code requirements. Energy Trust’s EPS New Construction offering will update its baseline to align with the 2018 WSEC in October 2021. To remain eligible for EPS New Construction incentives from Energy Trust of Oregon, builders in Washington will need to make design changes to exceed code requirements.   

The 2018 WSEC has seven categories where builders can obtain credits. For a medium-sized home (most EPS homes fall into this category), a minimum of six energy credits are required to meet code. There are countless ways to achieve code, but implementing these four key upgrades will go a long way toward qualifying for Energy Trust EPS New Construction cash incentives:    

  1. Install efficient gas furnace. To qualify for cash incentives, homes in Washington must use natural gas provided by NW Natural for primary space heating. Builders should install a gas furnace that is at least 95% efficient. 
  2. Install the HVAC system inside. Designing for interior HVAC units requires moving the entire heating and cooling system inside the conditioned space. The most common barrier builders face in this scenario is deciding where to put the ductwork in a single-level home. Typical strategies include dropping the ceiling and soffit in hallways to hide the ductwork or creating a soffit up into the attic.   
  3. Reduce air leakage. To reduce air leakage, consult the air barrier and sealing checklist, ensure your ventilation system matches the airtightness of the home and consider air leakage during the following building phases:
    Design: Ask for recommendations from your verifier about which ventilation system will best accommodate the home’s airtightness.
    Rough inspection: Discuss good air sealing techniques with your verifier and implement whatever is relevant. 
    Final inspection: Ask your verifier to perform a blower door test to measure the home’s air changes per hour (ACH) and determine if there are additional air leaks to seal.  
  4. Choose high-performance wallsBuilders can receive energy credits by employing advanced wall designs that are anywhere from 5% to 40% more efficient than R-21. Advanced wall designs may include exterior insulation, high-efficiency windows, a thermal break shear wall or a double-stud construction.