Hjerim

Summary
The house is available for 12,000 gold, purchasing all upgrades costs an additional 9,000 gold. (You must complete Rescue from Fort Neugrad or win the war for the Stormclocks, or Imperial Legion before buying this house.) A part of the quest Blood on the Ice takes place here, although it is not required to have completed the quest before buying the house, in order to purchase the upgrades for the house, the quest must be completed. The quest is automatically gained when entering the house for the first time, if not previously completed. When completing the quest, talking to the Steward allows the Dragonborn to buy upgrades for Hjerim.

Upon the Dragonborn becoming Thane of Eastmarch, Calder is pronounced Housecarl to the Dragonborn and lodges at Hjerim. If you complete Blood on the Ice, you can purchase a clean-up for 500 septims. It is recommended you do this clean-up first. Hjerim is the biggest house from all purchasable houses in Skyrim. Hjerim has 2 floors, a secret chamber, and the biggest rooms and most storage space of all the houses. Hjerim also has a very useful armory with mannequins, display cases, shelves, weapon and shield racks. Hjerim has a secret chamber behind the wardrobe where the Butcher kept the parts of his victims so he could reanimate his sister. After the cleanup the mess goes away, but the secret room stays.

Item Displays

 * 7 Weapon Wall Plaques
 * 2 Weapon & Shield Wall Plaques
 * 3 Sword Display Cases
 * 1 Weapon Rack
 * 3 Mannequins
 * 4 Dagger Display Cases
 * 12 Book Shelves
 * See Windhelm Home Decorating Guide for more detailed descriptions.

Bugs

 * I have personally had the instance where i was able to purchase Hjerim for 10,050 gold. i asked to buy it, Jorlief so come back when you have enough, i asked him again, and he then he agreed. taking the gold and i actually did get the key.
 * I personally finished the second half of the "Blood on the Ice" quest by killing the killer in broad daylight(?which one, wuuthrad or calaxico?). It did not lead to a bounty or any legal trouble. The quest was finished, but when I was given the house (I took the Stormcloaks quest line) I was unable to buy the clean-up upgrade. There was still blood on the floor in the first room and I still was able to investigate many things in the house. This hasn't led to any glitches though. **EDIT OF ORIGINAL EDIT** I found the enchanting table and alchemy lab, but they were in the secret room that I recently found. The secret room still had the blood and skeletons and overall creepy nastiness, including the altar and the journal of the butcher. I recommend everyone finish the second half of the "Blood on the Ice" quest the normal way, and NOT by killing him in broad daylight like I did. Killing him in broad daylight doesn't allow me to purchase the clean up from the steward, leaves all the "mess," and still lacks the blacksmithing forge though I payed for it. My strong suggestion is to finish that quest the normal way and not try cut corners, as it were. (PC)
 * Buying the Bedroom upgrade removes the bedroom dresser and all of its contents.
 * Do not place ANYTHING in the blood spattered chest if you intend to purchase the Clean-up upgrade. As part of the upgrade, the chest will be removed from the house, along with all the items inside it.
 * Sometimes the weapon racks (confirmed ps3), wall mounts (confirmed ps3) and mannequins will not work. *Occasionally, displays will not work and may destroy items within.
 * All aspects of the Blood on the Ice quest must be completed, as the house appears to be quest sensitive. A common mistake is not investigating all the areas of the house, in the first part of Blood on the Ice. This cannot be done once the house has become available for purchase, as new furnishings take the place of investigation items. If these are left undone, they may result in broken container issues, as noted above.
 * Sometimes the Jarl's aide will say the house is unavailable, continuously.
 * If you place the Staff of Magnus on the weapons rack, the position of the staff will slowly migrate downwards, in short and sporadic intervals, through the floor and into the first floor. Also if you place the staff in the weapons case immediately across from the stairs it will hover in the air (PS3).
 * In some instances, even after purchasing the "Clean up the Murders" decoration from the Jarl's aide, the blood will still be present inside the house and the secret room will be as it was. However, weapon plaques will still be added and the bookshelf in the sacrificial altar area will be glitched.
 * Purchasing the living room upgrade before the "Clean up the Murders" upgrade will remove the option to clean up the mess, resulting in the same issue above.
 * One method of fixing the two above issues is to open the console, click on an item that should have been removed and type markfordelete. Do this for each object that should have been deleted and reload the area. Be sure to save, beforehand. Note that trying to remove the bloodstains on the floor using this method will remove the floor, leaving an opening to nothing.
 * There's also a method to remove the blood stains but it requires care (try at your own risk). Create a New Save file and open the console, click on the blood stains (or any object that has them) and type markfordelete then do a quicksave and quickload, as expected both the floor and objects will have disappeared, just load the save file that was created first and everything will be back but without the blood (not guaranteed to always work).
 * On occasion the speech options for buying upgrades will not go away. If chosen again, the appropriate coin will be lost, without changing anything.
 * For an unexplained reason, two of the master bedroom dagger racks are currently unusable, after storing daggers in them. More daggers may be added, causing clip issues with the old ones, though none may be removed. The other dagger racks are unaffected, as are all other displays.
 * Placing the Ghostblade on any of the plaques in the house will make it disappear, indefinitely.
 * If you complete the second half of Blood on the Ice after buying the bedroom upgrade, you'll get additional bedroom furniture. This includes bed, chairs, table and a small wardrobe, looking like those before the upgrade, through the upgraded furniture.
 * After buying the house upgrades, there may be an empty room just in front the master bedroom's doors. This room will be filled with furniture, the moment Thane of Windhelm is achieved. The Housecarl will live here. Therefore, if anything is left within this room, before the title of Thane has been bestowed, it may be stuck under or behind the new furniture.
 * The mannequin closest to the bedroom is bugged. If a piece of armor is placed upon it, Hjerim is exited and entered, it will have equipped Ebony Armor. The original armor is not lost and this bug may be exploited for coin. This bug is actually slightly more complicated, the piece that is replicated is a piece that is removed than going through the process of exiting and re-entering. So in this instance ebony armor was removed from the mannequin before so it is the piece being duplicated. It only works the one time for the single piece. I have tested this on three seperate characters with a daedric shield, a pair of iron boots and the Krosis mask. I'll leave it to one of the mods to edit this and give an example that more accuratly details the bug with an example.
 * The mannequin directly in front of stairs is bugged. After storing more that 1 piece of armor of 1 type (tested with helmets), it will after leaving the house and re-entering generate one of those helmets, which may be taken away and sold eventually, and this will not break the generating bug.
 * Sometimes, giving a mannequin Wolf Armor will make parts of the mannequin go invisible. This will not destroy the items.
 * It is possible to continuously purchase the Clean-up upgrade (confirmed on PS3, Xbox 360 and PC).
 * One of the dagger displays in the player's room is bugged (the one on top). Any dagger the player puts in it will dissapear, though the image of the dagger will still appear, it is impossible to retrieve it back. You may stack daggers in the display, but none will be retrievable. (PC and Xbox 360).
 * The chest at the base of the bed may not appear. The cause is unconfirmed, but is most likely from buying the house for less than the regular price.
 * Sometimes the helmet placed on a mannequin is invinsible and unable to see. The helmet is not lost and can be retrieved.
 * Sometimes the Master Bedroom may become bugged, in which, the player cannot enter the master bedroom. It is as if there is an invisible forcefield in the bedroom doorway, which will not allow the player to enter. Everything stored inside the master bedroom will from then on be unavailable. Current cause and/or solution for this bug is unknown. One cause seams to be the very large hit zone of some 2 handed weapons placed on the weapons rags on the right side of the door, removing the weapon from the rag solves it. (tested with Daedric Greatsword on PS3)
 * If you do not start the Blood on the Ice quest before retaking windhlem for the Empire you can be stuck in an endless loop with Jorleif that Hjerim needs to be cleaned up before you can purchase the house (XBOX360)
 * Equipping items directly in the mannequin menu will temporarily render the properties (i.e. improving & enchanting) of the items disappear, just unequip and then equip again will fix this. (PS3)