TK is closer to UA's A gates than LH, which is less than 10 min walk. Adding one or two minutes to LH lounge. Just keep walking. Both are located on right hand side if walking from A gates.

Z gates
 

What is the closer to the Z gates?

You will have take Air Train to Concourse B station from the Terminal station. LH is closer to the B station than TK. As mentioned earlier, it is 2 min walk between LH and TK lounges.

I personally think it's faster to take the underground tunnel to B and walk to TK/LH than wait for the train after clearing security. With the location of the Z gates think it is definitely faster. TK is closer to the underground tunnel by that whole 2 mins (or less).

Just went to TK (finally!) before an A gate UAX flight. Very close to the tunnel walkway. About 10 min to go up and over to low A gates. Check-in agent was a little confused with my virtual UC membership card but let me in. Said to bring my “Star gold card next time” (I’m silver). Food was as described many times here. As mentioned there was a bit of a wait in the PM for the bathroom (3 singles). There’s a nice kind of hidden upstairs area too.

Can you elaborate on the hidden upstairs area? Never noticed that before.

Right when you walk in, there are stairs there that you really don't notice. Upstairs is a small area with a table for eating and some couches. Definitely more quiet up there!

Here's a picture :

https://cimg5.ibsrv.net/gimg/www.fly...920c269e8c.jpg

What did the TK agent did to let you in with your virtual UC card?

At IAD, with a UC membership and flying in economy, which lounge have showers besides TK?

She scanned it after she scanned my boarding pass.

It was weird handing my phone to someone (twice). I guess I am just used to self scanner at UC/TSA and self entry gates newer UCs.

Do they have separate food service up there, or do you need to carry a plate up? (I've seen the stairs, just never bothered to climb them.)

Me either and can't count how many times I've been in the TK lounge. I can't even recall seeing it when the stairs are not roped off.

No services upstairs. Unfortunately, when the lounge is crowded, the small upstairs area often is, too. If you walk down the little corridor to the bar and look up, you can see if anyone is in there.

TK's neighbor, LH lounge, has showers in the lower level. I used it pre-pandemic.