Fallout Shelter
19 Achievements
A Better Future, Underground
Upgrade 20 Rooms to Level 3
12.55%
How to unlock the A Better Future, Underground achievement in Fallout Shelter - Definitive Guide
Simply create some living quarters (to ensure this is as cheap as possible, don't build it next to an already existing one), press and select to upgrade for 250. Then upgrade again for another 750. Destroy the room, build another, upgrade twice, then rinse and repeat until the achievement pops.
N.B as with all achievements in Shelter, progress is not cumulative across vaults, so this must be done in a single vault.
All rooms in the vault, with the exception of the elevator, can be upgraded to level 3. Each upgrade costs more caps than the last but improves the efficiency of that room by a pretty good amount. This achievement will unlock naturally as you play, but you can just build, upgrade, and destroy the same room over and over if you have the caps. Destroying a room refunds a small portion of the caps spent on the room, but it’s not much compared to the actual cost of building and upgrading. When 20 rooms have been upgraded to level 3, this achievement will unlock.
You can upgrade every room except Elevators, by highlighting them and pressing . This will cost a certain amount of Caps but they will produce more resources.
Upgrading rooms early on to Level 3, means the incidents that break out in them will greatly increase in difficulty. This especially dangerous with low-level dwellers inside those rooms so make sure to level up your dwellers and equip them with good weapons to deal with these incidents, before upgrading your rooms. Credit to Jester695 for this tip.
You can destroy rooms after upgrading them and they will still count for the trophy. The cheapest rooms to upgrade are the Living quarters, Water Treatment, Power Generator and Diners. They cost 100 Caps to build, 500 to upgrade to level 2 and 1500 to upgrade to level 3.