REVIEWED BLD2022-0882+Energy_Calculations+7.1.2022_12.45.02_PM+2967128R503.1.1 Building envelope. Building envelope assemblies that are part of the alteration shall comply with Section
R402.1.1 or R402.1.4, Sections R402.2.1 through R402.2.11, R402.3.1, R402.3.2, R402.4.3 and R402.4.4.
Exception: The following alterations need not comply with the requirements for new construction provided the
energy use of the building is not increased:
Storm windows installed over existing fenestration.
2. Existing ceiling, wall or floor cavities exposed during construction provided that these cavities are filled
with insulation. 2x4 framed walls shall be insulated to a minimum of R-15 and 2x6 framed walls shall be
insulated to a minimum of R-21.
3. Construction where the existing roof, wall or floor cavity is not exposed.
4. Roof recover.
5. Roofs without insulation in the cavity and where the sheathing or insulation is exposed during reroofing
shall be insulated either above or below the sheathing.
6. Surface -applied window film installed on existing single pane fenestration assemblies to reduce solar heat
gain provided the code does not require the glazing fenestration to be replaced.
R503.1.1.1 Replacement fenestration. Where some or all of an existing fenestration unit is replaced with a new
fenestration product, including sash and glazing, the replacement fenestration unit shall meet the applicable requirements
for U-factor and SHGC in Table R402.1.1. Where more than one replacement fenestration unit is being installed, an area -
weighted average of the U-factor and SHGC of all replacement fenestration shall be permitted to be used to demonstrate
compliance.
R503.1.2 Heating and cooling systems. New heating, cooling and duct systems that are part of the
alteration shall comply with Section R403.
Exceptions:
1. Where ducts from an existing heating and cooling system are extended, duct systems with less than 40 linear feet in
unconditioned spaces shall not be required to be tested in accordance with Section R403.2.2.
2. Existing duct systems constructed, insulated or sealed with asbestos.
R502.1.1.2 Heating and cooling systems. New heating, cooling and duct systems that are part of the addition shall comply
with Section R403.
Exception: The following need not comply with the testing requirements of Section R403.3.3:
1. Additions of less than 750 square feet.
2. Duct systems that are documented to have been previously sealed as confirmed through field verification
and diagnostic testing in accordance with procedures in WSU RS-33.
3. Ducts with less than 40 linear feet in unconditioned spaces.
4. Existing duct systems constructed, insulated or sealed with asbestos.
R503.1.3 Service hot water systems. New service hot water systems that are part of the alteration shall comply with
Section R403.5.
R503.1.4 Lighting. New lighting systems that are part of the alteration shall comply with Section R404.1.
Exception: Alterations that replace less than 50 percent of the luminaires in a space, provided that such
alterations do not increase the installed interior lighting power.
R503.2 Change in space conditioning. Any nonconditioned or low -energy space that is altered to become conditioned
space shall be required to be brought into full compliance with this code.