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energy efficiency standards established in this section. If a | waiver is granted under subsection 2 for a building to be remodeled | or a building that receives an addition, only the remodeled portion | of the building or the addition must conform to the following | minimum energy efficiency standards. |
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| A. All ceilings that face an outdoor or unheated space must | be insulated to an R-value of 57 or greater. |
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| B. All walls that face an outdoor or unheated space must be | insulated to an R-value of 38 or greater. |
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| C. All floors over unheated spaces must be insulated to an | R-value of 25 or greater. |
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| D. Slab-on-grade floors must have perimeter insulation of | either: |
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| (1) R-15 when the insulation extends downward from the | top of the slab to the design frost line; or |
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| (2) R-15 when the insulation extends around the | perimeter and horizontally or diagonally beneath or | away from the slab for a distance equivalent to the | depth of the frost line. |
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| E. All foundation walls adjacent to a heated space must be | insulated from the top of the foundation to the frost line | to an R-value of 19 or greater. |
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| F. All windows and glass in doors, when the glass in the | door constitutes 1/3 or more of the door area, must have a | total window unit R-value of 2.5 or greater. |
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G. All exterior doors must be insulated or equipped with a | storm door. |
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| H. All new construction and renovation must comply with | infiltration and ventilation standards established by the | commissioner commission. |
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| | 4. Performance-based compliance. Effective January 1, 1992, | the commissioner The commission may waive the requirements of | subsection 3 for any building if the commissioner commission | determines that the building's calculated annual energy | consumption is not greater than the annual energy consumption of | a similar building constructed in accordance with subsection 3. |
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| The commissioner shall commission may adopt rules that establish | a performance-based compliance procedure for residential |
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