## 1.5 Energy Design Rating (EDR)

EDR is a dimensionless ratio of the energy use of a proposed or standard design divided by the energy use of the reference design.

The EDR is a way to express the energy performance of a building using a scoring system where 100 represents the energy performance of a reference design building meeting the envelope requirements of the 2006 International Energy Conservation Code (IECC). The EDR is similar to the energy rating index in the 2015 IECC and the 2014 Residential Energy Services Network (RESNET) standard. A score of zero represents a building that has zero-net-energy consumption based on the TDV energy consumption. By combining high levels of energy efficiency with generating renewable energy or flexibility measures, a score of zero or less can be achieved.

Buildings complying with the current Building Energy Efficiency Standards are more efficient than the 2006 IECC, so most newly constructed buildings will have EDR scores below 100. Buildings with renewable generation (PV) can achieve a negative score. If an EDR is calculated for an older inefficient home, the score would be more than 100.

The EDR for newly constructed buildings has three components:

1. Efficiency EDR.

2. PV/flexibility EDR.

3. Total EDR.

The efficiency EDR is based on the energy efficiency features of the building. PV/flexibility EDR includes the effects of the PV system, battery storage system, precooling, and other demand-responsive measures. Total EDR combines the efficiency EDR and PV/flexibility EDR into one final score.

The efficiency EDR does not include solar electric generation but can include a self-utilization credit for batteries. The total EDR includes the effects of solar generation and any battery storage beyond the self-utilization credit.