How does Qatar’s outdoor air conditioning work? Thanks to air conditioning, temperatures at World Cup matches are expected to be about 68°F, no matter the conditions outside.

Extreme temperatures present a significant challenge to AC systems, which engineers and installers say are really only designed to keep indoor temperatures about 20 degrees cooler than outside.

Air conditioning accounts for 7% of global electricity and 3% of carbon emissions. Here's how to beat the heat—efficiently.