2009 IECC State Residential building Code (West Virginia)

Last updated: 22 February 2019
Notable requirements in the 2009 IECC:
· Building envelope must be caulked and sealed.
· Slab-on-grade insulation is R-10 to a depth of 2 feet.
· Supply ducts in attics must be insulated to R-8. Return ducts in attics and all ducts in crawlspaces,
unheated basements, garages, or otherwise outside building envelope must be insulated to R-6.
· All ducts must be sealed and either:
o verified by pressure testing – the duct system has to be tested and the air leakage out of ducts must be kept to an acceptable maximum level.
o installed entirely within the building thermal envelope – testing is not required if all ducts are inside the building thermal envelope (for example in heated basements), though the ducts still have to be sealed.
· Piping for hydronic (boiler) heating systems must be insulated to R-3.
· Although vapor retarders are not required by the IECC, the I-codes do set wall vapor retarder requirements in Section R601.3 of the 2009 IRC, and vapor retarders are required in Zone 5.
· Less insulation is allowed for mass walls and more insulation is required for steel framing.
· 50% of the lighting “lamps” (bulbs, tubes, etc.) in a building must be high efficacy. Compact fluorescents qualify, standard incandescent bulbs do not.
· Standard I-code administrative requirements (inspections, documentation) apply.
· A certificate must be posted near the electrical panel listing insulation levels and other energy efficiency measures.

2009 IECC:
Policy Requirement Level
Model Code

Development Authority: International Code Council

Implementation Authority: Local authorities

Prescriptive Compliance path
Occupiable space, excluding crawl spaces and garages

Energy Requirements:
U-Values (Btu/h.ft2) Floor Roof Walls
Climate zone 1 0.064 0.035 0.197
Climate zone 2 0.064 0.035 0.165
Climate zone 3A and 3B 0.047 0.035 0.141
Climate zone 4A and 4B 0.047 0.03 0.141
Climate zone 4C 0.033 0.03 0.082
Climate zone 5 0.033 0.03 0.082
Climate zone 6 0.033 0.026 0.06
Climate zone 7 0.033 0.026 0.057
Climate zone 8 0.028 0.026 0.057
U-Values (Btu/h.ft2) Windows
Climate zone 1 1.2
Climate zone 2 0.65
Climate zone 3A and 3B 0.5
Climate zone 4A and 4B 0.35
Climate zone 4C 0.35
Climate zone 5 0.35
Climate zone 6 0.35
Climate zone 7 0.35
Climate zone 8 0.35

The total glazed area may not exceed 18% of the conditioned floor area using the prescriptive method

SHGC (for all fenestration including skylights) is 0.30 W/m2.k for climate zones 1-3. No SHGC requirement for other zones

Skylights individually are 0.75 W/m2.k zones 1-2, 0.65 W/m2.k zone 3 and 0.60 W/m2.k zones 4-8

Air Leakage
7 ACH at 50Pa. The thermal envelope must be verified even when using the perscriptive method

Space Heating System
At least one thermostat shall be provided for each separate heating and cooling system.

Specific requirements exist for ducts, piping, ventilation, pool systems and snow melt systems

Requirements are relative to equipment size and building type.

Water Heating System
All circulating service hot water piping shall be insulated to at least R-2 and have automatic or accessible manual switches to turn off the pump when the system is not in use

A minimum 50% of lamps in permanently installed lighting fixtures shall be high-efficacy lamps.

Renewable Energy
Pools deriving >60% heating energy from site-recovered or solar energy are exempt from pool specific energy saving measures

End-uses considered:
Space cooling, Space heating, Water heating, Ventilation, Lighting interior, Lighting exterior
Performance Compliance path
Not a requirement / performance based elements are based on a reference model and are relative to energy costs

End-uses considered:
Water heating, Ventilation, Space heating, Space cooling, Lighting interior, Equipment
Climate zones

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