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Housing Perspectives

Research, trends, and perspective from the Harvard Joint Center for Housing Studies

Decarbonizing Housing: The State of US Residential Electrification

The fuels we use in our homes have wide-reaching effects: nearly one-fifth of the nation’s carbon dioxide emissions come from the residential sector. The debate over mandating changes in these fuels has been hotly contested, however, as evidenced by the 2019 Berkeley, California policy to ban new gas hookups (which was recently overturned in court) and the fracas over a rumored federal ban on gas stoves. Nevertheless, residential electrification—the conversion of on-site fossil fuel use to electricity for households—was a central piece of the Inflation Reduction Act, which dedicated billions of dollars to help households make the switch, and many state and local governments are prioritizing it as well. The current state of residential electrification can provide insight into how households living in existing homes will be affected by these policies and how implementation will be affected by current patterns of use.

How many of the nation’s households are using only electricity for household needs like heating varies widely by region and depends on multiple factors including climate, energy grids, state utility regulations, and local policies. The share of households that were exclusively using electricity in 2020 ranged from 6 percent in Michigan to 77 percent in Florida (Figure 1). Most households use both fossil fuel and electricity, which leads to significant variation in home systems and equipment. Some end uses are nearly universally electric, including lighting, refrigerators, and TVs. Other uses, however, can be fueled by either source. Space heating and water heating are the two largest uses of household energy, accounting for 43 and 18 percent of all household energy use, respectively. Both can be alternately powered, as can equipment like stovetops and ovens.

Figure 1: Residential Electrification Varies Widely by State and Use

Space Heating

Nationally, 36 percent of households used electricity for their main space heating system in 2020, according to the most recent Residential Energy Consumption (RECS) data. The highest shares of households with electric heat were in the Southeast, and the lowest shares were in colder or more rural states, especially in the northernmost parts of the country. Using heat pumps for space heating is one of the cornerstones of residential electrification efforts but due to high upfront costs, this technology was still relatively uncommon in 2020, when 15 percent of households (17 million) used central or ductless (also known as mini-split) heat pumps for their main space heating. Most households (53 percent) used natural gas for heat and just over 10 percent used fuel oil, propane, wood, or another energy source. Natural gas is delivered through a vast network of pipelines but its reach is limited, which makes periodically delivered fuels such as propane more common in rural areas.

There is a stark divide along tenure lines when it comes to electric heat, which is used by half of renter households but less than one-third of homeowner households (Figure 2). This tenure difference is likely why electric heat is more common in mobile homes and multifamily buildings compared to single-family homes. However, renters are still more likely than homeowners to have electric heat even within multifamily buildings (58 percent versus 38 percent, respectively). Households in older houses are much less likely to have electric heat than those in newer houses, and electric heat is also less common among higher-income households.

Figure 2: Residential Electrification by Demographics and Housing Characteristics

Water Heating

Electric water heating is more common than electric space heating, with 46 percent of households using electricity for their main water heating system in 2020, almost equivalent to the 48 percent of households who used natural gas for water heating. Only 6 percent of households used a different fuel source, primarily fuel oil (3 percent) or propane (2 percent). The Southeast had the highest shares of households with electric water heating, in particular Florida (88 percent) and South Carolina (77 percent), and there were notably high shares in the Pacific Northwest and mid-Atlantic as well. Storage tank heaters are the most common type of electric water heating, but there are also electric heat pump water heaters on the market that qualify for federal tax incentives under the Inflation Reduction Act.

As with space heating, electric water heating is more common among renters than homeowners, and it is less common among higher-income households. It is particularly common in mobile homes (where fully three-quarters of households used electric water heating in 2020) and is least likely in single-family homes. Newer homes are generally more likely to have electric water heating as well.

Cooking

Unlike for both space and water heating, most households (57 percent) used only electricity for cooking in 2020, according to RECS data. This far outpaced natural gas cooking, which was used by 28 percent of households, though another 11 percent of households used some mixture of gas and electricity for cooking. Electric induction cooktops are more efficient than both gas and conventional electric cooktops but they remained quite rare in 2020, used by only 3 percent of households. As with space and water heating, electric cooking is most common in the Southeast, but it is also quite common in the Midwest. The states with the lowest shares of electric cooking were not regionally grouped but are among the nation’s most populous: California (27 percent), New Jersey (28 percent), Illinois (30 percent), and New York (30 percent).

Renters are more likely than homeowners to have electric cooking but unlike with space and water heating, there are no large differences by housing type and there is no linear relationship between housing age and electric cooking. There is a clear negative relationship with household income, however, which is likely related to the perception of natural gas as a preferable cooking fuel.

These patterns make it clear that there is a great deal of room for electrification policies to encourage households to switch to electric, especially for space heating. Homeowners, households in single-family homes, and higher-income households are the least likely to have electrified their heating and cooking systems, which makes them an obvious focus for electrification policies. While electrification among these households would achieve further decarbonization, there are perhaps more equity benefits in targeting lower-income households, renter households, and those in older housing units. This is especially true when this switch can provide cost savings, given the high share of households struggling with energy insecurity.

It should be noted, however, that the promise of electrification is highly contextual. The emissions reductions gained by switching from on-site fossil fuel combustion to electricity depend on how electricity is generated in the local power grid, with a fossil-fuel-dependent grid offering much less in the way of emissions reductions than a completely renewable grid. Most grids are somewhere in between, so benefits differ by state. The potential is also dependent on the technology used; for example, the most common type of electric heat is resistance (e.g. baseboard) heating, which is typically the cheapest to install but most inefficient and expensive to operate. The type of fossil fuel being replaced matters as well, and studies have found that fuel oil and propane are ‘low-hanging fruit’ for electrification since they are typically more expensive than electricity and have higher emissions than electricity or natural gas. Lastly, this analysis of electrification relied on data from 2020, before the passage of the Inflation Reduction Act and other electrification-related policies at state and local levels, so it is likely that the country has become more electrified since—though to what extent and where remains to be seen.