A recent analysis published in the journal Science challenges conventional wisdom on whether to repair or replace cars and household appliances from an environmental perspective. Researchers found that switching from a gasoline vehicle to a new electric vehicle (EV) — even if it involves scrapping a brand-new gas car — typically results in a lower carbon footprint over the vehicle’s lifetime.

Elliott Campbell, a professor of environmental studies at the University of California, Santa Cruz, and Roland Geyer conducted a comprehensive analysis of lifetime emissions across thousands of transportation scenarios. Their findings reveal that in 92 percent of cases, replacing a gasoline car with an EV immediately after purchase yields lower overall emissions, even when accounting for the energy-intensive manufacturing of electric batteries.

The core explanation lies in the energy demands during manufacturing versus use. While producing machines consumes energy and generates emissions, the majority of lifetime emissions come from fuel consumption during operation. Internal combustion engines convert only about 16 to 25 percent of gasoline energy into motion, wasting roughly 70 percent as heat. Conversely, EVs convert approximately 90 percent of electricity into driving power, partially thanks to regenerative braking.

Campbell estimates that replacing a gas vehicle with an EV upon purchase can reduce lifetime carbon emissions by around 56 percent, with emissions “payback” occurring within three years of driving. The environmental benefits grow further the earlier the swap occurs. The decision’s impact also depends on factors like the vehicle's efficiency, the electricity generation mix on the grid, and battery manufacturing processes. Even annual mileage as low as 4,000 to 7,000 miles is sufficient to make switching beneficial.

However, some exceptions remain. Switching from a fuel-efficient hybrid like a Toyota Prius to a large EV powered mainly by coal-generated electricity could increase emissions. These edge cases are diminishing as grids become cleaner and EV technology advances.

The research applies beyond vehicles to energy-using appliances such as dishwashers, refrigerators, laptops, and phones. The ratio of energy used in manufacturing versus usage determines whether it is better to repair or replace an item. For small electronics, most emissions stem from manufacturing, so extending their lifespan through repair is often more sustainable. By contrast, for heavily used appliances that consume significant energy during operation, replacing older devices with more efficient models may reduce overall emissions.

Usage intensity is a critical consideration. For example, a seldom-used dishwasher may not warrant replacement despite high operational emissions, while a frequently operated device could benefit from an upgrade. Clothes washers have notably improved efficiency, using up to 70 percent less energy than models from three decades ago, bolstering the case for timely replacement.

Experts emphasize that decisions should consider personal circumstances, usage patterns, and local energy sources. Battery production and grid cleanliness are improving, strengthening the environmental case for EVs and efficient appliances. With gas prices rising and EV costs declining, electric vehicles are becoming more economically competitive, particularly in the used car market, where total ownership costs can be lower than those of gasoline vehicles.

Consumers are encouraged to utilize tools that estimate product lifetime emissions, evaluate repair options, and consider efficiency and repairability ratings when purchasing. Emerging “right to repair” legislation aims to make fixing products easier amid concerns that manufacturers restrict access to parts and diagnostics.

When retiring old machines, scrapping the least efficient units generally benefits the climate most. Reselling newer but aging products can displace older, less efficient models in circulation, further reducing emissions.

As technology evolves rapidly, the traditional approach of keeping products “for life” is being reevaluated in light of environmental priorities. While repair and reuse remain vital, in some cases, replacing older machines with cleaner, more efficient alternatives provides the greater climate benefit.