## 3.1 Calculation Procedure

To calculate the EDR, the user enters the proposed home with additional inputs for PV as described in Section 3.3.

The software calculates the proposed design energy use and the standard design energy use in accordance with the normal compliance rules. A third annual simulation is performed to determine the reference design energy use as described in Section 3.2.

EDR calculations are based on the total energy use with units of kTDV/ft2 with an adjustment to maintain similar ratings with different fuel types. The total energy use includes the energy use associated with the space heating, space cooling and water heating used in compliance calculations plus the energy use for inside lighting, appliances, plug loads and exterior lighting.

There are adjustments made to these EDR calculations to address the issue that the 2006 IECC includes efficiency specifications that result in significantly different levels of total energy use in the reference design for gas and electric equipment and appliances. These adjustments are needed to ensure that homes using gas water ‘heating equipment and gas appliances are not penalized in the EDR results, as compared to homes using electric water heating equipment and electric appliances. This adjustment provides EDRs for gas and electric homes that implements a fuel neutral approach in the reference design total energy use.

Four quantities are reported for the EDR ratings. The EDR of the standard design building is provided to illustrate how the 2016 standard design compares with the reference design. The EDR score of the proposed design is provided separately from the EDR value of installed PV so that the effects of efficiency and renewable energy can both be seen. The final EDR for the proposed building includes both the effects of efficiency and PV.

The EDR values are calculated for each end use and fuel type and then summed for the total EDR

as follows:

Where:

EU standard = Standard Design Energy Use (kTDV/ft2)

EU reference = Reference Design Energy Use (kTDV/ft2)

EU proposed = Proposed Design Energy Use (kTDV/ft2)

PV proposed = Proposed PV Energy Generation (kTDV/ft2)

EU adjusted = EU reference / Adjustment (kTDV/ft2)

Adjustment = 1 for all end uses that are electric; or

Adjustment = Ratio from Table 30 for all end uses that are gas.

#### Table 30: EDR Adjustments by End Use for Gas Fuel Type

Climate Zone | Single Family Space Heating | Single Family Water Heating | Single Family Appliances | Multi Family Space Heating | Multi Family Water Heating | Multi Family Appliances
1 | 1.01 | 0.44 | 0.59 | 0.99 | 0.49 | 0.57
2 | 1.02 | 0.46 | 0.59 | 1.01 | 0.51 | 0.57
3 | 1.16 | 0.46 | 0.59 | 1.17 | 0.50 | 0.57
4 | 1.04 | 0.47 | 0.59 | 1.03 | 0.52 | 0.57
5 | 1.05 | 0.45 | 0.60 | 1.04 | 0.51 | 0.58
6 | 1.17 | 0.50 | 0.60 | 1.15 | 0.56 | 0.58
7 | 1.22 | 0.47 | 0.59 | 1.36 | 0.52 | 0.57
8 | 1.20 | 0.50 | 0.60 | 1.21 | 0.56 | 0.58
9 | 1.17 | 0.50 | 0.60 | 1.17 | 0.58 | 0.58
10 | 1.12 | 0.51 | 0.60 | 1.09 | 0.58 | 0.58
11 | 1.00 | 0.48 | 0.59 | 0.98 | 0.54 | 0.57
12 | 1.05 | 0.47 | 0.59 | 1.03 | 0.53 | 0.57
13 | 1.03 | 0.49 | 0.59 | 1.01 | 0.55 | 0.57
14 | 1.01 | 0.51 | 0.60 | 0.99 | 0.57 | 0.58
15 | 1.13 | 0.59 | 0.60 | 1.10 | 0.65 | 0.58
16 | 0.95 | 0.48 | 0.60 | 0.91 | 0.53 | 0.58

The ratios were calculated by using a prototype analysis once with gas fuel type for space heating, water heating and appliances, and once with electric fuel types. The ratio is the end use energy for the EDR reference building run with gas (kTDV/ft2) divided by the run with electric (kTDV/ft2).