The expression in bold

[motico]

Does the expression in bold mean that the fans need too much energy to operate?

"The problem with the fans is twofold: first, they are heavily energy intensive, and, second, they are prone to breaking down."

[Barb_D]

It means they use a lot of electricity. I wouldn't say "too much" based only on the phrase in bold, but coupled with the idea that it's a problem and you can infer that it's too much

[motico]

Thank you.