In this report, the authors consider how the County of Los Angeles might develop its maximum indoor temperature threshold ordinance for single-family rental houses. The analysis includes various types of active and passive cooling across multiple weather conditions to calculate differences in energy use, greenhouse gas emissions, the burden on the electric grid, and affordability for landlords and tenants.

Identifying Resilient, Sustainable Cooling Strategies for Los Angeles

How Might Landlords of Single-Family Homes Meet Indoor Temperature Thresholds?

Hye Min Park, Kelly Klima, Sophia Charan, Javier Rojas Aguilera

ResearchPublished Mar 31, 2025

In 2024, the Los Angeles County Board of Supervisors began developing an ordinance that would establish a maximum indoor temperature threshold for rental units. Officially, this ordinance would affect only renters living in the unincorporated parts of the county; however, the authors of this report explored the implications of what might happen if every city within the county adopted the ordinance. A simple way to comply might be for a landlord to provide some form of air conditioning, but RAND researchers conducted an analysis of how different ways to meet the indoor temperature threshold for single-family rental houses might lead to differences in energy use, greenhouse gas emissions, the burden on the electric grid, and affordability for landlords and tenants.

The authors' research demonstrates that the ordinance and implementation plans should focus on safe temperatures for at least one room; promote passive and active cooling strategies to ensure safe indoor temperatures; and reduce barriers to adopting strategies that minimize installation cost, electric grid impact, energy bill impact, and greenhouse gas emissions.

This report might be of interest to County of Los Angeles technical and academic stakeholders who are interested in learning details about the authors' analysis of the proposed indoor temperature threshold ordinance. The findings in this report are also applicable to a broader variety of stakeholders in any region that is considering maximum indoor temperature threshold regulations. For a related video that presents these topics from a higher level, see "Keeping Los Angeles Renters Cool."

Key Findings

  • Adding more than 124,000 window air conditioners in the near term would stress the electric grid.
  • When window units are used to cool the entire home, the temperature threshold might still be exceeded, and renters might encounter higher electricity bills.
  • Efficiency ratings and compressor systems both affect peak energy use.
  • Higher-efficiency systems lower peak and annual energy demand but raise installation costs.
  • Passive cooling increases the amount of time the maximum indoor temperature stays below the threshold and lowers annual energy demand but does not reduce peak load unless fully implemented.
  • During a power interruption, there is a trade-off between the intensity and duration of unsafe indoor temperatures when looking at passive cooling measures.
  • Cooling only one room reduces peak energy use across all passive cooling levels and weather conditions compared with cooling an entire home.
  • A higher thermostat setpoint, such as 82°F, reduces annual energy use but increases unsafe conditions and does not always reduce peak load when compared with a 75°F thermostat setpoint.
  • All whole-home active cooling methods fail to meet safe indoor temperature thresholds during the worst heat waves when combined with some passive cooling methods.

Recommendations

  • The Los Angeles County Board of Supervisors' ordinance to establish a maximum indoor temperature threshold should focus on safe temperatures for at least one room rather than the entire home.
  • The ordinance, implementation plans, and incentives should promote passive cooling to reduce overall greenhouse gas emissions and energy bills and combine passive and active strategies to ensure safe indoor temperatures.
  • If higher levels of passive cooling are costly and difficult to implement, it is crucial for the ordinance, implementation plans, and incentives to prioritize higher efficiency ratings and zone control for air conditioning.
  • Implementation plans should include outreach that addresses different compliance options and their usage in a way that can promote safe indoor temperature and address electricity bill concerns. People who are especially vulnerable to heat should consider prioritizing their health over public requests to reduce energy demand and should not increase the thermostat temperature to conserve electricity or enroll in programs that give the utilities the ability to modify air conditioning thermostat settings during heat waves. Instead, efforts for those especially vulnerable to heat should focus on reducing the cooling space to maintain safe temperatures and lower energy consumption.
  • Related implementation plans and incentive structures should reduce barriers to adopting strategies that minimize installation cost, grid impact, energy bill impact, and greenhouse gas emissions while ensuring safe indoor conditions.

Topics

Document Details

Citation

RAND Style Manual

Park, Hye Min, Kelly Klima, Sophia Charan, and Javier Rojas Aguilera, Identifying Resilient, Sustainable Cooling Strategies for Los Angeles: How Might Landlords of Single-Family Homes Meet Indoor Temperature Thresholds? RAND Corporation, RR-A3563-1, 2025. As of April 30, 2025: https://www.rand.org/pubs/research_reports/RRA3563-1.html

Chicago Manual of Style

Park, Hye Min, Kelly Klima, Sophia Charan, and Javier Rojas Aguilera, Identifying Resilient, Sustainable Cooling Strategies for Los Angeles: How Might Landlords of Single-Family Homes Meet Indoor Temperature Thresholds? Santa Monica, CA: RAND Corporation, 2025. https://www.rand.org/pubs/research_reports/RRA3563-1.html.
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