As a router, it's quiet in a desktop environment, unless the CPU is fully loaded. For a bedroom, silent is better than quiet, which could justify investment in a fanless case for mini-ITX. These are not cheap, e.g. Streacom or Akasa.
Broadwell NUCs are available on eBay and Newegg has a matching Akasa Plato X case for $100. With an SSD, that has no moving parts. But only dual core, single NIC.
In most cases the beefiest air cooler + the lowest tolerable fan curve (meaning no overheating) will do the job just fine, especially if the CPU TDP is between 35-65W. Alternatively you can also limit the CPU power usage by disabling turbo or doing other tricks that forces it to run slower, but more efficiently.
Woah these are really cool. $$$ for what amounts to bling in my case but I might still be interested in something like this. The NUCs are great but I don't see many of them on the second hand market. At least not as many as these thin clients.
Broadwell NUCs are available on eBay and Newegg has a matching Akasa Plato X case for $100. With an SSD, that has no moving parts. But only dual core, single NIC.