I see many people have devices that are not assigned to a room, and looking through the documentation I was wondering if anyone is using rooms as functions, or if this is somewhere else in the UI.
I was thinking of naming rooms "Lighting", "Ventilation", "Sensors". Does that make sense, or is it best to just leave devices unassigned? Would it pose any issues later on organizing it that way? I haven't created a dashboard yet, I am still working on the basics.
Everything will be in one room-less building (or single room building if you prefer).
That sounds like a good plan to me. It really comes down to how your homepage will be organized, and the ability to sort by room on the device list page. Sorting by room would group all your Lighting, ventilation, and sensor devices together in the list.
I use normal room names and function names together, especially for virtual devices function. Any virtual devices I use with Alexa are in the room "Alexa", but real devices use the room name they are in.
With that, I never really use the Homepage, nor do I sort by room in the device list. I normally just use the search bar to find my devices in the list and room name ends up being pretty meaningless to me. I usually just assign a room because it asks when the device is added.
My take is that "rooms" help make a list of hundreds of devices more manageable. I use rooms for most devices, but for some other things I created a 'room' that is more their function, as you propose.
Ultimately it's up to you, as you are the one who will use it...
There isn't any reason you can't do that. I think you could (should) do whatever makes sense for your house. Actually grouping by device type is actually a neat idea for some things.
Grouping by room helps apps like Room Lighting where you can select a whole room with one selection, instead of having to pick 20 different devices. So you have to consider how you create rooms, if you want to use functions like that.
Rooms are a work in progress, and a pretty recent addition to the hub. I think some feedback as to how people are using rooms, or want to use rooms that doesn't exist (a feature request post) would help guide the future of rooms.
I would see it as "a way people are trying to use the Room feature to satisfy their need", focusing on the need rather than attributing that to be a feature request of the room feature per se. Just because the question / request is phrased to include the Room feature doesn't mean it needs to be something rooms needs to deliver....
Personally I feel it feels like a request for a different way to categorise devices....
(tags... tags.... tags... ) Oh hang on, forgot we actually got that.... I guess it would be a case of being able to reference that in parts of the UI...
My comment about tags started out as a tongue-in-cheek reference to a topic that was discussed multiple times in the past with varying opinions about how and where it should be implemented and used. Then I had a nagging suspicion I had seen it added somewhat recently.
Looking at the documentation:
Tags: Allows adding or removing tags and assigning them to this device. The primary purpose of tags at this time is to add additional text that can be searched on to find this device, e.g., to filter the Rooms or Devices lists when using the search feature to filter the list
In terms of what @skylandgrowers is asking for it is hard to know whether this would be suit the need for grouping devices by "function", it very much depends on where this is intended to be used. If it is just to make finding devices in the devices page a little easier, then it looks like it would, but if it is in other parts of the UI, it might need some more investigation. It does sound like searching devices in other parts of the UI apart from the devices page may also make use of tags.
It could probably all be done with different dashboards, I'm new to Hubitat and only recently got access to the admin side of it (don't ask). Plans are to automate a 3000 sq ft poly high tunnel, and since technically its only one room (we might have "zones" which could also be rooms, but I figure, if I want to see all the temp sensors, having a room called "sensors" or "temperature" if I wanted to separate that from humidity, lux, etc... and another called "ventilation" to see what fans are on, what sidewall motors are up or down, etc...
Thank you everyone for your opinions though, it sounds like I can just sorta do whatever works for me, I like that flexibility. I was worried that certain functions might not like that, like the smart lighting stuff I've read a bit about.
I didn't know "tags" existed. Looking at it, I wish there were a way to multi-select devices and then batch apply tags. With hundreds of devices, adding them now seems more trouble than it's worth. Adding an editable tag column to the device view, functioning like the rooms column would accomplish much the same thing.
Sounds like you'll be delving into the dashboard arena.
Good luck with that.
I suppose there are choices, just make sure it can't dry up and blow away.
What you said about temps in one place reminded me of my simple (stock) setup.
It's three columns wide so I can see it on my phone without scrolling left to right.
I scroll up and down, which is fine by me.
Only one dashboard, many small tiles.
Not for everyone.
I will have to read more before really getting into it, I am doing my best to take note of all the things I've read that interest me before adding all the devices. I want to take everyone's best experiences that align with my uses and grow from there.
So with dashboards, it doesnt matter what room something is in, you can just rearrange it as you like? I plan for this to mostly be hands off and setup like IFTTT (for the older automation crowd) but likely with Node-RED. So hopefully hands-off for the most part.
) Oh hang on, forgot we actually got that.... 
