12.1.4 Compliance under the Building Energy Use Budget method requires a detailed energy analysis, using a conventional simulation tool, of the Proposed Design. A life-cycle cost analysis shall be used to select the fuel source for the HVAC systems, service hot water, and process loads from available alternatives. The Annual Energy Consumption of the Proposed Design with the life-cycle cost-effective fuel selection is calculated to determine the modeled energy consumption, called the Design Energy Use.

12.1.5 The Design Energy Use is defined as the energy that is consumed within the five foot line of a proposed building per ft2 over a 24 hour day, 365-day year period and specified operating hours. The calculated Design Energy Use is then compared to a calculated Energy Use Budget.

12.1.6 Compliance. The Energy Use Budget is determined by calculating the annual energy usage for a Reference or Prototype Building that is configured to comply with the provisions of Section 11.0 for such buildings, except that the fuel source(s) of the Prototype or Reference Building shall be the same life-cycle cost-effective source(s) selected for the Proposed Design. If the Design Energy Use is less than or equal to the Energy Use Budget then the proposed design complies with these standards.

12.1.7 This section provides instructions for determining the Design Energy Use and for calculating the Energy Use Budget. The Energy Use Budget is the highest allowable calculated annual energy consumption for a specified building design. Designers are encouraged to design buildings whose Design Energy Use is lower than the Energy Use Budget. Incorporated in this section is an optional lifecycle cost economic analysis procedure that may be used by the designer to examine the economic feasibility of all

energy design alternatives and to produce a more optimum design.

12.2 Determination of the Annual Energy Budget

12.2.1 The Energy Use Budget shall be calculated for the appropriate Prototype or Reference Building in accordance with the procedures prescribed in section 11.2 with the following exceptions: The Energy Use Budget shall be stated in units of Btu/ ft2 yr and the simulation tool shall segregate the calculated energy consumption by fuel type producing an Energy Use Budget for each fuel (the fuel selections having been made by a life cycle cost analysis in determining the proposed design).

...

Where EUB1, EUB2, EUB, are the calculated annual energy targets for each fuel used in the Reference or Prototype building and f1, f2, . . . f¡ are the energy conversion factors given in Table 12-1. In lieu of case by case calculation of the Energy Use Budget, the designer may construct Energy Use Budget tables for the combinations of energy source(s) that may be considered in a set of project designs, such as electric heating, electric service water, and gas cooling or oil heating, gas service water and electric cooling. The values in such optional Energy Use Budget tables shall be equal to or less than the corresponding Energy Use Budgets calculated on a case by case basis according to this section. Energy Use Budget tables shall be constructed to correspond to the climatic regions and building types in accordance with provisions for Prototype or Reference Building models in Section 11.0 of these standards.

12.3 Determination of the Design
Energy Use

12.3.1 The Design Energy Use shall be calculated by modeling the Proposed Design using the same methods, assumptions, climate data, and simulation tool as were used to establish the Energy Use Budget, but with the design features that will be used in the final building design. The simulation tool used shall segregate the calculated energy consumption by fuel type giving an annual Design Energy Use for each fuel. The sum of the Design Energy Uses multiplied by the fuel conversion factors in Table 12-1 yields the Design Energy Use for the proposed design:

DEU DEU1×f1+DEU2×f2+....+DEU, ×f1 Equation 12-2

Where fi, f2, f, are the fuel conversion factors in Table 12-1.

12.3.2 Required Life Cycle Cost
Analysis for Fuel Selection

12.3.2.1 Fuel sources selected for the Proposed Design and Prototype or Reference buildings shall be determined by considering the energy cost and other costs and benefits that occur during the expected economic life of the alternative.

12.3.2.2 The designer shall use the procedures set forth in Subpart A of 10 CFR Part 436 to make this determination. The fuel selection life cycle cost analysis shall include the following steps:

12.3.2.2.1 Determine the feasible alternatives for energy sources of the Proposed Design's HVAC systems, service hot water, and process loads.

12.3.2.2.2 Model the Proposed Design including the alternative HVAC and service water systems and conduct an annual energy analysis for each fuel source alternative using the simulation tool specified in this section. The annual energy analysis shall be computed on a monthly basis in conformance with section 11.0 of these standards with the exception that all process loads shall be included in the calculation. Separate the output of the analysis by fuel type.

12.3.2.2.3 Determine the unit price of each fuel using information from

local

the utility or other reliable source. During rapid changes in fuel prices it is recommended that an average fuel price for the previous twelve months be used in lieu of the current price. Calculate the annual energy cost of each energy source alternative in accordance with procedures in Section 11.0 for the Design Energy Cost. Estimate the initial cost of the HVAC and service water systems and other initial costs such as energy distribution lines and service connection fees associated with each fuel source alternative. Estimate other costs and benefits for each alternative including, but not necessarily limited to, annual maintenance and repair, periodic and one time major repairs and replacements and salvage of the energy and service water systems. Cost estimates shall be prepared using professionally recognized cost estimating tools, guides and techniques.

12.3.2.2.4 Perform a life cycle cost analysis using the procedure specified in section 12.3.2.

12.3.2.2.5 Compare the total life cycle cost of each energy source alternative. The alternative with the lowest total life-cycle cost shall be chosen as the energy source for the proposed design.

Use Budgets for Prototype and Reference Buildings and the Design Energy Use for the Proposed Design. In order to maintain consistency between the Energy Use Budgets and the Design Energy Use, the input assumptions stated in section 11.5 are to be used.

12.5.2 The terms Energy Cost Budget and Design Energy Cost or Consumption used in section 11.0 correlate to Energy Use Budget and Design Energy Use, respectively, in section 12.0.

12.6 The Simulation Tool

12.6.1 The criteria established in Section 11.0 for the selection of a simulation tool shall be followed when using the compliance path prescribed in Section 12.0.

12.7 Life Cycle Cost Analysis Criteria

12.7.1 The following life cycle cost criteria applies to the fuel selection requirements of this chapter and to option life cycle cost analyses performed to evaluate energy conservation design alternatives. The fuel source(s) selection shall be made in accordance with the requirements of Subpart A of 10 CFR Part 436. The implementation calculations for the methodology of Subpart A of 10 CFR Part 436 is provided in National Bureau of Standards Handbook 135 entitled "Life Cycle Cost Manual for the Federal Energy Management Program.' When performing life cycle cost analyses of optional energy conservation opportunities the designer may use the life cycle cost procedures of Subpart A of 10 CFR Part 436 or OMB Circular A-94 or an equivalent procedure that meets the assumptions listed below:

12.7.1.1 The economic life of the Prototype Building and and Proposed Design shall be 25 years. Anticipated replacements or renovations of energy related features and systems in the Prototype or Reference Building and Proposed Design during this period shall be included in their respective life cycle cost calculations.

12.7.1.2 The designer shall follow established professional cost estimating practices when determining the costs and benefits associated with the energy related features of the Proto

type or Reference Building and Proposed Design.

12.7.1.3 All costs shall be expressed in current dollars. General inflation shall be disregarded. Differential escalation of prices (prices estimated to rise faster or slower than general inflation) for energy used in the life cycle cost calculations shall be those in effect at the time of the life cycle cost calculations as published by the Department of Energy's Energy Information Administration.

12.7.1.4 The economic effects of taxes, depreciation and other factors not consistent with the practices of Subpart A of 10 CFR Part 436 shall not be included in the life cycle cost calculation.

Subpart B-Voluntary Performance Standards for New Non-Federal Residential Buildings [Reserved]

Subpart C-Mandatory Performance Standards for New Federal Residential Buildings

§ 435.300 Purpose.

(a) This subpart establishes voluntary energy conservation performance standards for new residential buildings. The voluntary energy conservation performance standards are designed to achieve the maximum practicable improvements in energy efficiency and increases in the use of non-depletable sources of energy.

(b) Voluntary energy conservation performance standards prescribed under this subpart shall be developed solely as guidelines for the purpose of providing technical assistance for the design of energy conserving buildings, and shall be mandatory only for the design of Federal buildings.

(c) The energy conservation performance standards will direct Federal policies and practices to ensure that cost-effective energy conservation features will be incorporated into the designs of all new residential buildings designed and constructed by and for Federal agencies.

§ 435.301 Scope.

(a) The energy conservation performance standards for new Federal residential buildings will apply to the design of all new residential buildings except multifamily buildings more than three stories above grade.

(b) The primary types of buildings built by or for the Federal agencies, to which the energy conservation performance standards will apply, are:

(1) Single-story single-family residences;

(2) Split-level single-family residences;

(3) Two-story single-family residences;

(4) End-unit townhouses;

(5) Middle-unit townhouses;

(6) End-units in multifamily buildings (of three stories above grade or less);

(7) Middle-units in multifamily buildings (of three stories above grade or less);

(8) Single-section mobile homes; and (9) Multi-section mobile homes.

(a) "Building” means any new residential structure (1) that includes or will include a heating or cooling system, or both, or a domestic hot water system, and (2) for which a building design is created after the effective date of this rule.

(b) "Building design" means the development of plans and specifications for human living space.

(c) "Conservation

Optimization

Standard for Savings in Federal Residences" means the computerized calculation procedure that is used to establish an energy consumption goal for the design of Federal residential buildings.

(d) "COSTSAFR" means the Conservation Optimization Standard for Savings in Federal Residences.

(e) "Energy conservation voluntary performance standard" means an energy consumption goal or goals to be met without specification of the method, materials, and processes to be employed in achieving that goal or goals, but including statements of the requirements, criteria and evaluation methods to be used, and any necessary commentary.

or

(f) "Federal agency" means any department, agency, corporation, other entity or instrumentality of the executive branch of the Federal Government, including the United States Postal Service, the Federal National Mortgage Association, and the Federal Home Loan Mortgage Corporation.

(g) "Federal residential building" means any residential building to be constructed by or for the use of any Federal agency in the Continental U.S., Alaska, or Hawaii that is not legally subject to state or local building codes or similar requirements.

(h) "Life cycle cost" means the minimum life cycle cost calculated by using the methodology specified in Subpart A of 10 CFR Part 436.

(i) "Point system” means the tables that display the effect of the set of energy conservation options on the design energy consumption and energy costs of a residential building for a particular location, building type and fuel type.

(j) "Practicable optimum life cycle energy cost" means the energy costs of the set of conservation options that has the minimum life cycle cost to the Federal government incurred during a 25 year period and including the costs of construction, maintenance, operation, and replacement.

(k) "Project" means the group of one or more Federal residential buildings to be built at a specific geographic location that are included by a Federal agency in specifications issued or used by a Federal agency for design or construction of the buildings.

(1) "Residential building" means a new building that is designed to be constructed and developed for residential occupancy.

(m) “Set of conservation options” means the combination of envelope design and equipment options that influences the long term energy use in a building designed to maintain a minimum ventilation level of 0.7 air changes per hour, including the heating and cooling equipment, domestic hot water equipment, glazing, insulation, refrigerators and air infiltration control measures.