# Energy Star Performance

NOTE: as of March 2002, the commercial spaces for which an Energy Star
label can be obtained include: offices, K-12 schools, Supermarket /
Grocery, Hotel / Motel, and Hospitals.

Energy efficiency performance will be determined using the Energy Star
Target Finder rating tool for new building designs. During design an
estimate of annual energy use by fuel type for each portion of a
building that can be handled by the tool: office, etc., must be
developed in order to obtain a design rating.

Planned building characteristics required for use in the Energy Star
rating tool are required as input to calculate the expected Energy Star
rating. For office buildings these characteristics include gross floor
area that is: office, computer center,
attached/unattached-ventilated/unventilated parking garage. The on-line
forms must be run through to verify the data needed.

A rating of 75 or higher is required to achieve an Energy Star label.
The recommended rating of the design is 85, as actual performance is
often less than design, and achieving a design level of 85 helps assure
a rating of 75 in use. Actual energy performance must be tracked to
submit for an Energy Star label following occupancy. The Energy Star
performance rating of the occupied building can provide some evaluation
of design team, construction team, and commissioning team performance.

Sometimes, a building may have spaces that are not typical for an office
or other covered building type, or only a portion of a building has such
space in it. In such cases, consideration should be given to submetering
of either the atypical spaces or the applicable space to arrive at a net
energy use for the applicable space. The energy use for this space is
referred to as the net energy use below.

Net energy use equals total energy use for the building minus energy use
for atypical spaces, such as large process energy use in major computer
data centers that are very energy intensive. Gross floor area for the
typical space equals gross floor area of the entire building minus the
gross floor area of the atypical spaces. Remaining gross floor area that
consists of more typical computer centers or parking garages (and type),
which the tool can adjust for, must also be known. Total annual net
building energy use for each fuel is entered in the Energy Star Target
Finder rating tool, together with the required characteristics, to
obtain a rating:

<http://yosemite1.epa.gov/estar/business.nsf/content/nbd_targetfinder.htm>

(click on the Enter Target Finder icon on the right after familiarizing)

An estimate of Energy Star performance should be obtained for each stage
of design (e.g., conceptual, schematic, design development stages).

Key mechanical considerations relative to an Energy Star rating include:

-   Enthalpy or heat recovery in the IAQ/exhaust/pressurization system

-   Effective zoning of the IAQ/exhaust/pressurization and heating /
    cooling systems

-   Minimization of fan power requirements and use (small, local,
    single-zone systems for heating/cooling systems and smaller,
    effectively zoned systems for IAQ)

-   Occupancy-based control of heating and cooling, with systems off
    when unoccupied

    Key electrical considerations include:

-   Effective integration and use of daylighting to increase quality and
    offset electrical lighting

-   Occupancy control of lighting and daylighting

-   Efficient lighting sources and lighting power densities below 1 Watt
    per square foot

-   Effective integration of occupancy, daylighting, and central system
    control

-   Efficient and not excessive outdoor lighting

-   Efficiency of LAN/WAN operation so power can be switched lower as
    use lowers

-   Energy Star computers, equipment, and appliances, with energy-saving
    features activated and minimal number of computer workstations that
    have to be left activated 24/7 (meaning that workstations actually
    power off when not in use for 45-60 minutes, and this also means a
    boot procedure that does not take excessive time)

-   Effective selection of any required data transfer procedures to
    minimize number of 24/7 workstations

-   Efficient motors and transformers, well matched to requirements and
    well integrated with mechanical systems efficiency needs as required

-   Separate metering of process energy and exterior security lighting
    energy so it can be subtracted from total energy for an Energy Star
    label

    **If LEED energy credit 1 points are desired, consider:**

    In addition to the Energy Star rating, the design is required to
    obtain 2 credit points under Energy Credit 1 of the LEED rating
    system, which means that the proposed design will use 20% less
    energy than a base compliance (minimally compliant) building,
    generally using the Energy Cost Budget method in ASHRAE Std
    90.1-1999, Section 11. The energy values used to calculate the
    percent reduction are: building energy equal to total simulated
    building energy use minus simulated computer use and other plug load
    use. Any process energy should also be excluded when calculating the
    percentage reductions.

    The features and approaches that lead to an Energy Star rating will
    differ somewhat from those that allow the 2 credit points under LEED
    Energy Credit 1.

Download this document from:
<http://eber.ed.ornl.gov/commercialproducts/Design.htm>

This document is not necessarily definitive, and comments are
appreciated.

Email: <macdonaldjm@ornl.gov>