UC Davis

Electrification, particularly switching out gas furnaces with electric heat pumps, is increasingly seen as an important decarbonization pathway for residential buildings but could impact low-income residents through higher energy bills. Bill impacts for rent-restricted affordable housing are particularly hard to assess due to barriers discouraging electrification and difficulties with obtaining household level bill data. This study predicts energy consumption and bill impacts using a simple linear regression model and actual bill data from 78 households across three affordable housing properties in California. Two electrification scenarios are considered: electrification of heating and cooling systems (partial electrification) and full electrification. Estimated household energy savings from electrification ranged from 2-62% across the 78 households. Despite this, 26% of the households had estimated bill increases after partial electrification, and 31% after full electrification. For one property with gas water heating, only 8% of households had predicted bill increases after full electrification, compared to 70% and 45% for the properties where cooking was the only remaining gas usage, suggesting that partial electrification may have higher bill savings potential than full electrification unless the existing gas end uses include water heating. For one property where data was available after a partial electrification retrofit, 30% of households saw bill increases despite predicted decreases. Since actual bill impacts can differ greatly from predicted, the results demonstrate the importance of property-specific and household-level analyses both pre- and post-retrofit to support electrification decision-making and policy. This study also highlights the need for electrification policy alternatives to consider difficulties with resident bill data collection, unfavorable rates, and outdated Utility Allowance policy to encourage electrification while mitigating potential bill impacts.