12.3.2.

(1) All walls, ceilings, floors, windows and doors that separate heated space from unheated space, the exterior air or the exterior soil shall have thermal resistance ratings conforming to this Subsection.

(2) Insulation shall be provided between heated and unheated spaces and between heated spaces and the exterior, and around the perimeter of concrete slabs-on-ground.

(3) Reflective surfaces of insulating materials shall not be considered in calculating the thermal resistance of building assemblies.

(4) Except as permitted in Articles 12.3.2.3., 12.3.2.4., 12.3.2.6., 12.3.2.7. and 12.3.2.9., the minimum thermal resistance of insulation shall conform to Table 12.3.2.1.

(1) Except for a foundation wall, the insulated portion of a wall that incorporates wood stud framing elements that have a thermal resistance of less than RSI 0.90 shall be insulated to restrict heat flow through the studs by a material providing a thermal resistance at least equal to 25 per cent of the thermal resistance required for the insulated portion of the assembly in Sentence 12.3.2.1.(4).

(2) Except as provided in Sentence (3), the thermal resistance of the insulated portion of a building assembly in Sentence 12.3.2.1.(4) that incorporates metal framing elements, such as steel studs and steel joists, that act as thermal bridges to facilitate heat flow through the assembly, shall be 20 per cent greater than the values shown in Table 12.3.2.1., unless it can be shown that the heat flow is not greater than the heat flow through a wood frame assembly of the same thickness.

(3) Sentence (2) does not apply to building assemblies incorporating thermal bridges where the thermal bridges are insulated to restrict heat flow through the thermal bridges by a material providing a thermal resistance at least equal to 25 per cent of the thermal resistance required for the insulated portion of the assembly in Sentence 12.3.2.1.(4).

(1) The thermal resistance values in Table 12.3.2.1. for exposed roofs or ceilings may be reduced near eaves to the extent made necessary by the roof slope and required ventilation clearances, except that the thermal resistance of insulation at the location directly above the inner surface of the exterior wall shall be at least RSI 2.1.

(1) Sentence (2) applies to construction for which a permit has been applied for before January 1, 2009.

(2) Foundation walls enclosing heated space shall be insulated from the underside of the subfloor to not less than 600 mm below the adjacent exterior ground level.

(3) Sentence (4) applies to construction for which a permit has been applied for after December 31, 2008.

(4) Foundation walls enclosing heated space shall be insulated from the underside of the subfloor to not more than 380 mm above the finished floor level of the basement.

(5) The insulation required by Sentences (2) and (4) may be provided by a system installed,

(a) on the interior of the foundation wall,

(b) on the exterior face of the foundation wall, or

(c) partially on the interior and partially on the exterior, provided the thermal performance of the system is equivalent to that permitted in Clauses (a) or (b).

(6) Insulation around concrete slabs-on-ground shall extend not less than 600 mm below exterior ground level.

(7) The minimum RSI value required in Table 12.3.2.1. for the perimeter of a slab-on-ground is permitted to be reduced by 50% if the underside of the entire slab-on-ground is insulated.

(8) If a foundation wall is constructed of hollow masonry units, one or more of the following shall be used to control convection currents in the core spaces,

(a) filling the core spaces,

(b) at least one row of semi-solid blocks at or below grade, or

(c) other similar methods.

(9) Masonry walls of hollow units that penetrate the ceiling shall be sealed at or near the ceiling adjacent to the roof space to prevent air within the voids from entering the attic or roof space by,

(a) capping with masonry units without voids, or

(b) installation of flashing material extending across the full width of the masonry.

(1) Where an enclosed unheated space is separated from a heated space by glazing, the unheated enclosure may be considered to provide a thermal resistance of RSI 0.16.

(1) Except as permitted in Sentence (2), all windows that separate heated space from unheated space shall have,

(a) an overall coefficient of heat transfer of not more than 2.0 W/ m²∙°C, or

(b) an energy rating of not less than,

(i) 17 for operable windows, and

(ii) 27 for fixed windows.

(2) A basement window that incorporates a loadbearing structural frame shall be double glazed with a low-E coating.

(1) Except for doors on enclosed unheated vestibules and cold cellars, and except for glazed portions of doors, all doors that separate heated space from unheated space shall have a thermal resistance of not less than RSI 0.7 where a storm door is not provided.

(2) All sliding glass doors that separate heated space from unheated space shall have

(a) an overall coefficient of heat transfer of not more than 2.0 W/ m²∙°C, or

(b) an energy rating of not less than 17.

(1) When electric space heating is used in a dwelling unit, all sliding glass doors that separate heated space from unheated space or the outdoors shall have,

(a) an overall coefficient of heat transfer of not more than 1.6 W/ m²∙°C, or

(b) an energy rating of not less than 25.

(2) When electric space heating is used in a dwelling unit, all windows that separate heated space from unheated space or the outdoors shall have,

(a) an overall coefficient of heat transfer of not more than 1.6 W/ m²∙°C, or

(b) an energy rating of not less than,

(i) 25 for operable windows, and

(ii) 35 for fixed windows.

(1) Except as provided in Sentences (2) and (3), log wall construction and post, beam and plank construction shall have a minimum thermal resistance of RSI 2.1 for the total assembly.

(2) The thermal resistance value in Sentence (1) for the total wall assembly may be reduced to not less than RSI 1.61 if,

(a) the thermal resistance of insulation for the exposed roof or ceiling required in Table 12.3.2.1. is increased by an amount equivalent to the reduction permitted in this Sentence, and

(b) for log walls, the logs have tongue-and-groove or splined joints.

(3) Where milled log walls are installed, the thermal resistance value in Sentence (1) for the total wall assembly does not apply if,

(a) the mean thickness of each log is not less than 150 mm,

(b) the thermal resistance of insulation for the exposed roof or ceiling required in Table 12.3.2.1. is increased by RSI 0.53, and

(c) the logs have tongue-and-groove or splined joints.