Recently, USGBC approved a CIR regarding savings from key cards in hotel rooms (5/14/07 - see attached). We are requesting that under LEED-NC savings from submetering of multi-family buildings be accepted as an exceptional calculation method. There are no code requirements for submetering of apartment or condominiums in multi-family buildings. Submetering of utilities for individual tenants or owners in multi-family buildings is an added construction cost, but significant energy savings result. Studies have shown that a minimum of 10% energy savings are achieved once individual metering is implemented. Research done by the New York State Energy Research and Development Authority (NYSERDA: http://www.nyserda.org/publications/SubmeterManual.pdf) estimates that installing sub-meters in a master-metered building can reduce building-wide electricity consumption by 10-26%. In Ontario, Canada, non-electrically heated submetered apartments have shown a 16-22% reduction in electricity consumption while electrically heated apartments with submetering showed a reduction in consumption of 30% (http://www.frpo.org/Document/Topics&Issues/UtilitiesEnergy/Options%20to%...). Based on these studies and the fact that submetering is not required by the energy codes, we request that USGBC allow an exceptional calculation method to account for the savings from submetering. We are proposing that 10% cost savings of all submetered end uses be allowed by the calculation method. So, if a living unit is submetered for electricity and gas, the project can assume 10% cost savings for each of these fuel sources based on the energy use within the unit. Energy use in common areas of the building would be excluded from the calculation. Is this acceptable? Related CIR\'s 4/12/2007 - Credit Interpretation Request Per ASHRAE 90.1-1999 and 2004 mandatory requirements, hotel guestrooms must include a master control device at the main room entry that controls all permanently installed luminaires and switched receptacles. We are considering automating this lighting control with the use of a key card-activated master switch. The control would turn off all permanently installed and switched receptacle lighting after the guestroom is unoccupied for more than 30 minutes. The controls may also be configured to allow the interior window shades to be closed automatically when the guestroom is unoccupied. Monitored data for hotel lighting usage patterns is provided in a 1999 Research study by Erik Page and Michael Siminovitch entitled "Lighting Energy Savings in Hotel Guestrooms." This study indicates an average daily usage of nearly 8 hours for the bathroom light, 2 hours for the desk table lamp, 5 hours for the bedside lamp, and 3 hours for a floor lamp. The study also showed that the high use fixtures (the bathroom fixture and bed lamp) did not experience a significant drop during typically unoccupied periods. Instead, these lights were 20% - 25% on during these periods; and the lighting energy consumed during these periods accounted for about 60% of the total guestroom lighting energy consumption. Another study for ACEEE entitled the "Emerging Energy-Savings Technologies and Practices for the Building Sector as of 2004" projects an energy savings for key card lighting controls of 30%. Based on the information provided in these two studies, it seems reasonable to credit hotel guestroom lighting fixtures with a 30% energy savings for automated control based on room occupancy. We propose to model the energy savings achieved through automated control of lighting and interior window shades as an exceptional calculation measure. The lighting savings would be calculated by adjusting the proposed case lighting schedules for all permanently installed and switched receptacle fixtures to 50% lower than the budget case for the percentage of guestrooms modeled as unoccupied. Lighting during all occupied periods will be modeled identically to the budget case. The guestroom lighting energy savings achieved through this measure for the affected lighting fixtures would be 30%. Automated control of the blinds is intended to limit solar heat gains, since the building is in a hot dry climate. The blinds will be modeled identically during the occupied periods as 50% open during daylit hours, and 25% open during evening hours. During unoccupied periods, the shades will be modeled as 25% open. As with all exceptional calculation measures, the savings for this automated control measure will include a narrative documenting the lighting and interior shading schedules and assumptions, and the calculation methodology, and will include a separate line item on the ECB report documenting the savings achieved from this measure. We would like confirmation whether the proposed modeling methodology is acceptable, or direction regarding any modifications that would need to be made to the proposed modeling methodology in order to comply with LEED ECB modeling requirements. 5/14/2007 - Ruling The applicant is requesting confirmation on the proposed strategy for two exceptional calculations. Based on the description of the lighting assumptions, the proposed approach is acceptable. In the LEED submittal please include a narrative documenting the lighting schedules and assumptions and the calculation methodology. Also include a separate line item on the ECB report documenting the savings achieved from this measure. Please provide enough detail in the documentation to allow the review team to ascertain the amount of credit claimed. Based on the description of the automated blinds, the assumptions concerning blind control are insufficient to model the proposed building.
The project team is inquiring as to whether or not sub-metering of multi-family residential buildings would be acceptable as an exceptional calculation method. The energy savings associated with sub-metering are due to a change in occupant behavior and not due to building efficiency. As a result, the schedules in the baseline case must be modeled identically to those in the design case. Therefore project teams may not claim credit for sub-metering of a multi-family residential building through the exceptional calculation method.