I use those Admirals’ Clubs regularly. They are OK. The food and drinks options are poor, but the showers are pretty nice. There are also some comfortable chairs which recline, which might be good for sleeping, although they can go quickly. The quiet rooms generally are quiet, but they don’t contain the reclining chairs (from memory).
It costs $50 for a day pass, so you can decide if that’s worth it to you.
Assuming you are in Terminal 3, it’s also worth checking out the Virgin America gates along concourse L, which have powerports, and the new Mexican place near Gate K8 or so (best food in the terminal).
It’s hard to find good info on spots in the airport, but Foursquare does mention:
New privacy station with nice seats and power (free) near Johnny
Rockets between T1 & T2
if you’re looking for a place to nap and recharge (pun intended), this may be it.
Apparently, several of the departure gates also include arm-less benches (airport sleepers’ dream!)
But possibly the most useful in terms of lounges, as you were asking:
Did you know you can buy a one day pass at any United Club? The C
concourse location is pretty roomy, has a “quiet” room, decent wines,
clean bathrooms. And, means not waiting out a delay at the gate.
I’ve not slept in this airport, so I can’t give you personal information. Nevertheless there is a site called “Sleep in Airports” that gives general information about sleeping in almost any airport. About Chicago O’Hare, this page says that you can sleep in a lounge for US$40-50, there are 3 hotels and if you are looking for a free nap you have some reviews about where and how to do it.
Credit:stackoverflow.com‘