There’s an old vaudeville joke about a man who walks into a doctor’s office. And it goes something like this:

“Doctor,” the man says, “it hurts when I do this.”

“Then don’t do that,” the doctor replies.

Amazon data-center guru James Hamilton alluded to this gag at a recent event in New York, using it to explain how data centers should treat power-sapping water chillers and air-conditioning units. If you’re running a data center, air conditioning hurts, he said, so you shouldn’t do it. Air conditioning is expensive, he explained, and in many cases it’s unnecessary. He advised data-center operators to run their facilities at higher temperatures and use outside air for cooling.

Traditionally, data centers have been kept very cold to protect servers and other equipment, but Hamilton is part of growing chorus telling operators they’ve gone too far. Google has advocated raising data-center temperatures for years, and just about all the big-name web outfits — including Google, Facebook, and Microsoft — have shown the world how they’ve managed to cool their data centers with outside air.

As the internet expands — and businesses bring more and more data online — it’s more important the ever that data centers keep their power consumption down. This not only saves money, it eases the burden on the environment, and raising temperatures is one rather easy way to save power. The trouble is that many data-center operators still refuse to dial up the savings. They’re afraid of damaging equipment. They’re afraid of voiding warranties. They’re afraid of change.

The Big Chill