Purpose
The WER (Water Efficiency Rating) Index is developed by RESNET (the Residential Energy Services Network) is a measure of the water usage of the rated building as compared to a hypothetical reference building which is built to current code requirements. A score of 100 indicates that the rated building operates the same as the reference home of the HERS Index (a standard new home constructed in 2006). A WER score of ≤ 85 means that the rated building must uses water ≥15% more efficiently than current codes requires.
Criteria
Complete the WER Index section of the HERS model for the home. All required inputs must be provided. Confirmation The WER collects information on indoor and outdoor domestic water use, including all indoor plumbing fixtures, pools and irrigation systems. The following information will need to be provided:
- Indoor plumbing fixture flow rate specifications for kitchen, lavatory, showers and toilets
- If project has a hot water recirculation pump, provide specifications on standard system pipe length, loop and branch length and pump watts. Follow RESNET approved procedure for determining pipe lengths
- If project has a domestic water heat recovery, document specifications on showers and DWHR efficiency 2
- If project has an outdoor irrigation system, determine sum of all irrigation flow rates through one of the following:
- Timed measurement in gallons per day
- If house has a digital water meter, time flow rate with all taps open to determine gallons per day
- A Residential Irrigation Capacity Index (RICI) may be applied to homes that document the total flow rate of all irrigation taps in relation the area of irrigated space. A RICI may adjust the portion of water use associated with irrigation (less the water use associated for pools) in the rated homes outdoor gpd by 10% for every point from a baseline RICI of 5:
- INSERT RICI CALCULATION
- Document if project has an inground pool
- Determine if project uses a water softener
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