Honkai Impact's Chibi Dorm feature is one that can be deeply personal. It's a place where you can express your own style, or enjoy the cute interactions between the Chibis. It however, also has a level system, required materials and a Tier system based on comfort.
Starting out, the dorm is a tiny 2 room area with cardboard furniture. You can slowly build up your dorm as you play. Each level requires more comfort and more materials. Be consistent in tending to your dorm like a garden and it will steadily grow. Leveling St. Freya's Dormitory and the Resort Dorm at the same time is taxing and unnecessary but there is no harm in having both.
These are the two Major materials you need to unlock things in the dorm. You can earn both by visiting your dorm and talking to your Valks (Not the stigmata chibis). Try making a habit of visiting when you login and just before you logout. You may also purchase them from the [Mithril] shop, but they are quite expensive. DO NOT purchase them unless you are certain you don't need the [Mithril].
Home Materials are required to Renovate your dorm, increasing it's capacity for Valks and Furniture alike. Home materials are more rare from valk dorm interactions.
Honkai Blocks are the basic crafting material for Furniture. You can use it to research new furniture OR craft copies of what you already own. Salvaging furniture returns 25% of its original cost.
Comfort is a score that appoximates your dorm's value. To level up your dorm, you need more and more of it. Comfort thresholds also award you with Dorm Superlatives to show off, and add value to your dorm. [Bare], [Simple], [Normal], [Nice], [Cozy] and [Exquisite]. The final two Tiers of [Luxurious] and [Magnificent] require you to purchase and upgrade the Beach Resort Dorm extension for 600 [Crystals].
Comfort can be attained by unlocking various dorm decorations. Keep in mind, you don't actually need to place the items to earn the comfort for them. Each piece of Furniture is worth some amount of comfort. The Furniture is broken up into categories such as, Small or Large. They cost some amount of Honkai Blocks to be crafted. For Example: the Wall Decoration - Black Cat Clock - is worth 10 Comfort and costs 110 [Honkai Blocks].
Crafting multiple copies of the same furniture still awards the same amount of comfort but there is a cap to how much comfort you can get from any given type of Furniture. The cap is Equal to the maximum number of something you can place in your dorm. In other words, if you can place 4 small furnitures in each of your 3 rooms you will be able to earn comfort from up to 12 small furnitures. For wallpapers, floors, and windows, the number is the same as how many rooms you have, not just the rooms you can use them in. In the St. Freya's Dormitory there are up to 3 rooms, so you can get Comfort from 3 carpets. If you own more furniture of a given type, it will automatically count the comfort of the highest values first.
There is a convenient list that will show you what you are getting comfort from inside the dorm UI. Just tap or click on the comfort score in the top center of the screen while you are in your dorm. This is what it looks like.
Any furniture that doesn't fit into a set is considered Unique. A good example is the [Red Fridge] from the Master's shop.
From the Furniture Collection/Crafting Interface you can view these unique items by tapping the Bookmark in the top center of the UI.
Some of these furnitures cost [Crystals] to make additional copies of, including the Red Fridge. It costs 800 [Crystals] to make an extra copy. The Top-Up rewards Starry Night piece can also be found and crafted once you own them.
This image I created only covers what is nessicary to maximize the basic dorm, but the furniture components are the best value for Comfort and can be applied to the Resort Dorm as well. Feel free to save this image as a quick guide to getting the most comfort as fast as possible.
This list is not so nice when it comes to decorating, but I tried my best to show off what you might be able to do with it. Remember, you only need to own the max comfort things. A collector who wants collection score from each of the furnitures, or a Designer who only wants furnitures they can work with can still max out their dorm comfort this way. C:
Here is all of the Dorm Furniture, sorted, and with additional information.
The embedded table is far too small to be useful, but it's a nice preview.
A Pop-Up Version of the Table
A Download of the Spreadsheet
Thanks so much to the people who run the Honkai Official wiki, even though the Dorm related sections are very out of date, it helped me so much in making this guide as well as the graphics for it. It also helped me get missing information for my spreadsheet.
And thanks to the Honkai Official Discord users who helped me understand how dorm comfort is calculated. It was them that helped inspire me to make this guide. Though, I wanted to know the best way to max comfort for myself. I didn't find anything on here about something like this so I decided to write this up and share it with everyone. Happy decorating.
Most of us have never seen a dorm pet, so I wanted to include a section about them but I couldn't say anything useful about them. If you have them they are free comfort and collection score, plus they liven up the dorm. *HINT HINT* Maybe, we could see a 2021 revival or even a new pet.