Cold-Water Pipe Insulation
Insulate cold-water pipes, or keep them out of unconditioned space.
Spec
Applies uniformly from Gold upward.
Scope
Cold-water supply lines running through any unconditioned space (attics, crawlspaces, exterior walls in cold climates, garages, vented soffits).
Requirements
- 01.
Insulate all cold-water supply lines passing through unconditioned space with closed-cell foam pipe sleeves of R-3 minimum (commonly 3/8" or 1/2" wall thickness).
- 02.
OR route all cold-water supply lines through conditioned space only, eliminating exposure to unconditioned conditions.
Documentation
Evidence the inspector / Institute will need.
- 01.
Photos of insulated cold-water runs showing foam sleeve coverage at joints, tees, and elbows.
- 02.
OR marked-up architectural drawings showing all cold-water lines routed through conditioned space (acceptable for new construction).
Guidance
Why insulate cold lines (not just hot)
Two reasons: (1) prevents condensation / "sweating" on cold pipes during humid weather, which can drip into wall cavities and cause hidden moisture damage; (2) reduces freeze risk in cold climates where pipes pass through unconditioned space. The energy savings are minor compared to hot-water insulation, but the moisture-management benefit is significant.
Note
Pair cold-water insulation with R-3+ hot-water insulation on the same runs. Hot-water insulation is a baseline expectation and reduces standby losses by 4-9% per the DOE.