Jevon's Paradox
Jevons paradox · Jevons effect · rebound effect · backfire effect
The observation that improvements in the efficiency of resource use often lead to increased total consumption of that resource rather than decreased consumption. As efficiency lowers the effective cost per unit, demand rises enough to offset or exceed the original savings.
Origin
English economist William Stanley Jevons introduced this idea in his 1865 book The Coal Question. He observed that James Watt's more efficient steam engine did not reduce Britain's coal consumption — it dramatically increased it by making coal power cheap enough to spread across industries. Jevons warned that efficiency alone could never be relied upon to conserve a finite resource.
Everyday Use
You buy a fuel-efficient car expecting to save money on gas, then find yourself driving more because each mile feels cheaper — and your total fuel spending barely changes. The same thing happens with LED lightbulbs (people leave more lights on), faster internet (we stream more video), and bigger hard drives (we hoard more files). Whenever an efficiency gain makes something cheaper, we tend to use more of it.