Crawlspace Insulation in Zone 2 (Hot)
The DOE recommends None required for crawlspace insulation in Climate Zone 2 (Hot). This zone has 2,000 heating degree days and 3,500 cooling degree days annually. The typical crawlspace cavity depth is 4 inches. States in Zone 2 include Alabama, Arizona, Florida, Georgia, Louisiana and 2 more.
Quick Facts
Insulation Not Required
The DOE does not require crawlspace insulation in Climate Zone 2 (Hot). The moderate climate in this zone does not create sufficient temperature differentials across this building component to justify the cost of insulation. However, local building codes may have different requirements, and adding insulation may still provide comfort benefits, noise reduction, and improved indoor air quality. Some utility programs and green building certifications may incentivize or require insulation for this component even in Zone 2.
If you choose to add insulation despite it not being required, even a modest R-5 to R-10 can improve comfort by reducing temperature differences between rooms and eliminating cold or hot spots on surfaces adjacent to unconditioned spaces. The cost of adding insulation during new construction is minimal compared to the total project cost, so many builders include it regardless of the code requirement.
Installation Guidance
Crawlspace insulation is not specifically required by the DOE in Climate Zone 2. In warm climates, crawlspaces are traditionally vented to allow moisture to escape. However, building science research has shown that conditioned, sealed crawlspaces perform better in most climates, including warm and humid zones. If your crawlspace has humidity or moisture problems, consider sealing and insulating the crawlspace walls even though it is not required. A vapor barrier on the ground floor combined with even minimal wall insulation can dramatically improve crawlspace conditions and indoor air quality.
States in Zone 2
The following states include areas within Climate Zone 2. Click any state to see its complete insulation requirements across all applicable zones.