Rebound effect
Also known as: Take-back effect
Efficiency gains get partly eaten up because the cheaper behavior invites more of it.
What it means
The rebound effect is the tendency for savings promised by an efficiency improvement to be partly eaten up by increased use of the very thing made more efficient. The mechanism is a change in effective price: when a behavior becomes cheaper in money, effort, time, or guilt, people simply do more of it, and whatever is freed up gets spent elsewhere on something that consumes resources too. A psychological variant runs through licensing, where the virtuous act itself feels like permission to relax. It shows up in energy and transport, where efficient appliances, insulation, and frugal cars deliver less than engineering models predict, and in dieting, exercise, and safety equipment. Estimates usually find partial rather than total offset; complete backfire, the Jevons paradox, is contested and rare. It matters because judging an intervention on the target behavior alone overstates what it actually delivers.
Examples
After insulating the house, a family nudges the thermostat up a couple of degrees because warmth now costs less, banking comfort instead of the full heating saving the retrofit promised.
Someone who starts cycling to work rewards the effort with a bigger lunch, so the calorie deficit the commute was meant to create quietly shrinks back to nothing.
A team adopts a tool that halves the time to produce a report, then commissions three times as many reports, and the hours saved reappear as extra work.
First described in Jevons (1865); Khazzoom (1980); Brookes (1990).