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Extreme heat days + cooling equity — climate risk by ZIP
The fastest-growing climate risk in 2026 is extreme heat. Heat killed more Americans in 2023-2025 than hurricanes + tornadoes + floods combined. ZIPs in the Sun Belt + arid West face the most exposure, but the Pacific Northwest's 2021 heat dome showed even cool-summer regions are vulnerable. Cooling equity — who has reliable AC vs. who doesn't — increasingly drives property decisions.
Published 2026-04-25 · Last reviewed 2026-04-27 · methodology
How extreme heat is measured
**Heat Index** = perceived temperature combining air temp + humidity. NOAA color codes: Caution (80-90°F), Extreme Caution (90-103°F), Danger (103-124°F), Extreme Danger (125°F+).
**WBGT (Wet Bulb Globe Temperature)** = used by military + sports for outdoor-activity safety. Includes solar radiation.
**Days >95°F per year** = simple metric used by climate models. Phoenix: 105+ days. Dallas: 60. Atlanta: 30. Boston: 12. Seattle: 5 (was 1 a decade ago).
**Heat dome events** = stagnant high-pressure systems trapping hot air. Pacific NW June 2021: peaked at 116°F in Portland (vs historical max 107°F).
EPA Climate Change Indicators + heat data
EPA publishes Heat Wave + Drought + Heat Index Days indicators at epa.gov/climate-indicators.
NOAA NWS publishes county-level heat-warning history + projected exposure.
**State heat-action plans** required in CA (SB 1383 expansion 2024), AZ, NV, OR, WA. Most other states lack formal plans.
Cooling-system inequity
Pacific NW: only ~35% of homes have AC (Portland metro 2024). Phoenix: 99%+. National average 91%.
Older urban housing stock + low-income neighborhoods = highest heat-mortality rates.
Heat pump installations 2024 outsold gas furnaces in the US for first time. Federal IRA Section 25C tax credit covers 30% up to $2,000 for heat-pump installs.
Cooling-as-utility programs: some cities (Phoenix, Las Vegas) treat AC failure as emergency similar to heating outage.
Property + insurance implications
**Insurance**: heat damage to roofs, AC compressors, refrigeration is rising claim category. 5-15% premium increases in Sun Belt 2024-2025.
**Resale**: homes WITHOUT AC in newly heat-exposed regions (PNW, New England) face 8-15% pricing pressure starting 2024.
**New construction**: California Title 24 requires high-efficiency cooling on new builds. Other states catching up via codes.
**Solar + battery**: battery backup during heat-wave + grid-stress events increasingly drives PV adoption.
What zipradar shows
Heat exposure is NOT in our 12-dimension federation. EPA Climate Change Indicators + NOAA NWS county-level data are canonical sources.
Pair /topic/wildfire-risk/[zip]/ (often correlated with heat) + /topic/air-quality/[zip]/ (heat → ozone formation) for climate-resilience profile.
Related zipradar topics
Glossary terms used here
WBGT (Wet Bulb Globe Temperature)
Heat-stress measurement combining air temp + humidity + solar radiation. Used by military + sports for outdoor-activity safety thresholds.
Heat pump
Reverse-cycle HVAC system that both heats AND cools — moves heat from outside to inside (or vice versa) instead of generating it.
IRA Section 25C (Energy Efficient Home Improvement Credit)
Federal tax credit for energy-efficiency upgrades — 30% up to $1,200 annual cap on insulation/windows + $2,000 on heat pumps + $150 on home audit.
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