Extreme weather kills thousands yearly - better fenestration would change that

Heat is a silent killer. It causes nearly as many deaths as all other weather-related events combined. It is often underreported, as the official cause of death is frequently listed as another condition exacerbated by heat. 

The Centers for Disease Control and Prevention estimates that 2,000 people die annually due to excessive heat, though that is likely an underestimate. Excessive cold also poses deadly risks. The oldest, youngest and health-compromised people are most vulnerable.
Studies show that housing conditions, especially in multifamily buildings (MFB), correlate with heat-related mortality. Adequate building envelope thermal performance plays a critical role in maintaining a human-surviv-able indoor environment.

A 2021 United States Department of Energy (DOE) study, PNNL report 32737, evaluates the potential for saving lives by constructing assisted living facilities, MFB and single-family homes to meet newer energy codes (IECC-R 2021 and ASHRAE Standard 90.1-2019) and the above-code 2021 Phius Core Standard.

Compared to most jurisdictions, the Phius standard requires better fenestration U-factors and often better solar heat gain management. It also demands superior air-leakage control and thermal bridge mitigation.

Study Highlights
The DOE study assessed buildings’ ability to maintain an indoor environment that humans can survive during extreme outside temperatures, coinciding with power outages. Findings include:

• Los Angeles (hot climate): Upgrading the median existing MFB’s envelope to an above-code standard was predicted to save 136 lives per extended heat event and 24 lives per cold event across the metro area when considering the MFB’s top and middle floors.
• Minneapolis (cold climate): The same upgrades were projected to save 27 and 26 lives per extended hot and cold event, respectively, across this metro area for the same MFB floors. The lives saved in Minneapolis are fewer because power outages are less likely than in Los Angeles.
• Nationwide impact: Across all climate zones, envelope improvements consistently save lives.

The study also evaluated the financial payback on the reduced mortality of the envelope performance investment. Estimating $10 mil-lion per life saved, the analysis found investing in above-code performance delivered a positive cost-benefit across all climate zones when factoring in:

•    Energy cost savings;
•    Reduced greenhouse gas emissions;
•    Avoided mortality; and
•    Avoided property damage.

These benefits are likely understated. The impact on occupants of buildings without HVAC or unaffordable usage during extreme weather and full power wasn’t assessed.

Policy Implications
U.S. building energy codes do not assess envelope changes through a life-safety lens. Based on PNNL report 32737, current fenestration and envelope standards would be much stricter if they did.