Delvin can provide five upgrade services for the Dawnstar Sanctuary. All upgrades are optional and can be delayed indefinitely without penalty.
Upgrade Item
Cost ()
New Banners
1,000
Master Bedroom
3,000
Poisoner's Nook
5,000
Torture Chamber
5,000
Secret Entrance
5,000
Total Cost
19,000
Recovering Costs
To recoup some of the cost of the newly remade sanctuary you can make use of the newly made torture chamber. If you pester each torture victim enough they will each reveal the location of a hidden cache of money somewhere in Skyrim for a total of 4 active locations at a time. Each location yields between 1,000 and 2,000 . There are a few methods to do this, from moderate to extreme.
Cast Soul Trap, as it does no damage but still seems to bother them.
Talk to them 4 times.
Go unarmed and just start wailing on them.
Just hurt them and heal them afterwards. Start again if they don't want to talk.
Trivia
The title for this quest is quoted from Gogron Gro-Bolmog's saying in Oblivion "Home is where you hang your enemy's head."
If you are going for the Achievement/Trophy requiring you to have 100,000 gold then this is a good boost towards that goal. 20,000 for completing the final Dark Brotherhood quest which will cover the cost of all upgrades with 1,000 left over. Though, you do not have to spend any of the 20,000 you receive on the Sanctuary. Purely optional as this quest will stay active until all items are purchased from Delvin.
Exploit
Cast Soul Trap repeatedly on the torture victims to increase your Conjuration to 100 and level up at the same time (can also be done on corpses). This takes an increasing amount of spells to level up, since Soul Trap is only an Apprentice level spell. Also there's no benefit to dual casting as the number of cast spells seems to be the trigger for leveling up, not the amount of Magicka used or "damage" inflicted. This can be done with most non harmful spells (i.e. Courage ) to level a particular skill easily.
Casting a Novice-level Destruction spell in one hand (such as Flames) and Healing Hands in the other on a victim in the torture chamber is a good exploit for leveling Destruction and restoration, as there are no repercussions for hurting them and they cannot fight back, as well as them always being in the same place.
You can also level sneak in the torture chamber. In the back right corner of the room when you walk in, equip something that gives Muffled Movement, such as the Shrouded Boots, or cast the Muffle spell (which also levels Illusion) and sneak towards the back corner. "Sheathing" the spell makes it harder to be detected. Put a rubber band on the controller and do something else to pass the time to make this less tedious.
Bugs
If the quest is not active while purchasing the upgrades it may not count towards the quest mark.
If you have bought all of the upgrades and the quest does not complete itself, just go back and talk to Delvin Mallory again and ask to purchase upgrades for the sanctuary and the quest will complete.
If you use the Wabbajack on a torture victim and hit them, they will be released from the shackles and roam freely around the sanctuary. If you try to talk to them after this they will say the same things as when they were shackled.