HOURS OF SAFETY IN COLD WEATHER: A FRAMEWORK FOR CONSIDERING RESILIENCE IN BUILDING ENVELOPE DESIGN AND CONSTRUCTION

The briefing introduces 'hours of safety' to measure building resilience during extreme cold events. Simulations in Duluth, Minnesota, show that high-performance envelopes, such as Passive House standards, maintain safe temperatures significantly longer than older or code-compliant homes, highlighting the potential for this metric to guide resilience planning and weatherization efforts.

• The 'hours of safety' framework quantifies the duration a home can maintain comfort and safety thresholds before indoor temperatures reach unsafe levels, which is critical for protecting vulnerable populations during increasing extreme weather events.
• Simulations of power outages during cold snaps reveal a stark difference in resilience based on building age and standards: homes built before 1950 fell below 40°F within 8 hours, while 2009 code-compliant buildings lasted 45 hours.
• High-performance building envelopes, specifically those meeting Passive House standards or net-zero energy ready (NZER) criteria, provide the highest level of resilience, maintaining temperatures above 40°F for over six days.
• There is a significant equity concern as low-income residents and seniors are more likely to live in older, poorly insulated housing that can reach life-threatening temperatures within 12 hours of a power outage.
• Passive House models showed a 90 percent reduction in 'severe cold stress hours' (temperatures below 40°F) compared to 1950s home models and performed over 7 percent better than net-zero energy ready buildings.
• The 'hours of safety' metric could be integrated into state and city policies, including residential energy disclosure policies, emergency response plans to identify vulnerable neighborhoods, and future building code developments.

APA

Ayyagari, S., Gartman, M., & Corvidae, J. (2020). HOURS OF SAFETY IN COLD WEATHER: A FRAMEWORK FOR CONSIDERING RESILIENCE IN BUILDING ENVELOPE DESIGN AND CONSTRUCTION. RMI. https://rmi.org/wp-content/uploads/2020/02/Hours-of-Safety-insight-brief.pdf

Chicago

Ayyagari, Sneha, Michael Gartman, and Jacob Corvidae. HOURS OF SAFETY IN COLD WEATHER: A FRAMEWORK FOR CONSIDERING RESILIENCE IN BUILDING ENVELOPE DESIGN AND CONSTRUCTION. RMI, 2020. https://rmi.org/wp-content/uploads/2020/02/Hours-of-Safety-insight-brief.pdf.

Wikipedia

{{cite report |last1=Ayyagari |first1=Sneha |last2=Gartman |first2=Michael |last3=Corvidae |first3=Jacob |title=HOURS OF SAFETY IN COLD WEATHER: A FRAMEWORK FOR CONSIDERING RESILIENCE IN BUILDING ENVELOPE DESIGN AND CONSTRUCTION |publisher=RMI |date=February 2020 |url=https://rmi.org/wp-content/uploads/2020/02/Hours-of-Safety-insight-brief.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{ayyagari2020hours, author = {Ayyagari, Sneha and Gartman, Michael and Corvidae, Jacob}, title = {{HOURS OF SAFETY IN COLD WEATHER: A FRAMEWORK FOR CONSIDERING RESILIENCE IN BUILDING ENVELOPE DESIGN AND CONSTRUCTION}}, institution = {RMI}, year = {2020}, month = feb, url = {https://rmi.org/wp-content/uploads/2020/02/Hours-of-Safety-insight-brief.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }