diff --git a/includes/controller/rooms_controller.php b/includes/controller/rooms_controller.php
index da5bdba1..4573409a 100644
--- a/includes/controller/rooms_controller.php
+++ b/includes/controller/rooms_controller.php
@@ -1,6 +1,7 @@
 <?php
 use Engelsystem\ShiftsFilterRenderer;
 use Engelsystem\ShiftsFilter;
+use Engelsystem\ShiftCalendarRenderer;
 
 /**
  * Room controllers for managing everything room related.
@@ -26,18 +27,27 @@ function room_controller() {
     }
   }
   
-  $shiftsFilter = new ShiftsFilter(false, [
+  $shiftsFilter = new ShiftsFilter(true, [
       $room['RID'] 
-  ], []);
-  $shiftsFilter->setStartTime(time());
-  $shiftsFilter->setEndTime(time() + 24 * 60 * 60);
+  ], AngelType_ids());
+  $selected_day = date("Y-m-d");
+  if (! empty($days)) {
+    $selected_day = $days[0];
+  }
+  if (isset($_REQUEST['shifts_filter_day'])) {
+    $selected_day = $_REQUEST['shifts_filter_day'];
+  }
+  $shiftsFilter->setStartTime(parse_date("Y-m-d H:i", $selected_day . ' 00:00'));
+  $shiftsFilter->setEndTime(parse_date("Y-m-d H:i", $selected_day . ' 23:59'));
   
   $shiftsFilterRenderer = new ShiftsFilterRenderer($shiftsFilter);
-  $shiftsFilterRenderer->enableDaySelection($days, EventConfig());
+  $shiftsFilterRenderer->enableDaySelection($days);
+  
+  $shifts = Shifts_by_ShiftsFilter($shiftsFilter, $user);
   
   return [
       $room['Name'],
-      Room_view($room, $shiftsFilterRenderer) 
+      Room_view($room, $shiftsFilterRenderer, new ShiftCalendarRenderer($shifts, $shiftsFilter)) 
   ];
 }
 
diff --git a/includes/model/AngelType_model.php b/includes/model/AngelType_model.php
index d01cf905..be15dc59 100644
--- a/includes/model/AngelType_model.php
+++ b/includes/model/AngelType_model.php
@@ -124,14 +124,11 @@ function AngelTypes() {
  * Returns AngelType id array
  */
 function AngelType_ids() {
-  $angelType_source = sql_select("SELECT `id` FROM `AngelTypes`");
-  if ($angelType_source === false) {
-    return false;
+  $result = sql_select("SELECT `id` FROM `AngelTypes`");
+  if ($result === false) {
+    engelsystem_error("Unable to load angeltypes.");
   }
-  if (count($angelType_source) > 0) {
-    return $angelType_source;
-  }
-  return null;
+  return select_array($result, 'id', 'id');
 }
 
 /**
diff --git a/includes/model/Shifts_model.php b/includes/model/Shifts_model.php
index 6721c30e..5a38abdd 100644
--- a/includes/model/Shifts_model.php
+++ b/includes/model/Shifts_model.php
@@ -49,7 +49,7 @@ function Shifts_by_ShiftsFilter(ShiftsFilter $shiftsFilter, $user) {
               AND `ShiftEntry`.`SID` = `Shifts`.`SID`
           )
       )";
-    } elseif ($_SESSION['user_shifts']['filled'][0] == 1) {
+    } elseif ($_SESSION['user_shifts']['filled'][0] == ShiftsFilter::FILLED_FILLED) {
       $SQL .= "
       AND (
           nat.`count` <= entries.`count` 
diff --git a/includes/view/Rooms_view.php b/includes/view/Rooms_view.php
index 4dbf2956..40ab9480 100644
--- a/includes/view/Rooms_view.php
+++ b/includes/view/Rooms_view.php
@@ -1,9 +1,11 @@
 <?php
 use Engelsystem\ShiftsFilterRenderer;
+use Engelsystem\ShiftCalendarRenderer;
 
-function Room_view($room, ShiftsFilterRenderer $shiftsFilterRenderer) {
+function Room_view($room, ShiftsFilterRenderer $shiftsFilterRenderer, ShiftCalendarRenderer $shiftCalendarRenderer) {
   return page_with_title(glyph('map-marker') . $room['Name'], [
-      $shiftsFilterRenderer->render() 
+      $shiftsFilterRenderer->render(room_link($room)) ,
+      $shiftCalendarRenderer->render()
   ]);
 }
 
diff --git a/includes/view/ShiftCalendarRenderer.php b/includes/view/ShiftCalendarRenderer.php
index 8356d033..41cf6f94 100644
--- a/includes/view/ShiftCalendarRenderer.php
+++ b/includes/view/ShiftCalendarRenderer.php
@@ -4,7 +4,61 @@ namespace Engelsystem;
 
 class ShiftCalendarRenderer {
 
-  public function __construct() {
+  /**
+   * 15m * 60s/m = 900s
+   */
+  const MINUTES_PER_ROW = 900;
+
+  private $shifts;
+
+  private $shiftsFilter;
+
+  public function __construct($shifts, ShiftsFilter $shiftsFilter) {
+    $this->shifts = $shifts;
+    $this->shiftsFilter = $shiftsFilter;
+  }
+
+  public function render() {
+    $rooms = $this->rooms();
+    $slotSizes = $this->calcSlotSizes($rooms);
+    
+    return '';
+  }
+
+  /**
+   * Calculates the slots for each room that appears in the shifts
+   */
+  private function rooms() {
+    $rooms = [];
+    foreach ($this->shifts as $shift) {
+      if (! isset($rooms[$shift['RID']])) {
+        $rooms[$shift['RID']] = $shift['room_name'];
+      }
+    }
+    return $rooms;
+  }
+
+  private function calcSlotSizes($rooms) {
+    $first_block_start_time = ShiftCalendarRenderer::MINUTES_PER_ROW * floor($this->shiftsFilter->getStartTime() / ShiftCalendarRenderer::MINUTES_PER_ROW);
+    $blocks_per_slot = ceil(($this->shiftsFilter->getEndTime() - $first_block_start_time) / ShiftCalendarRenderer::MINUTES_PER_ROW);
+    $parallel_blocks = [];
+    
+    // initialize $block array
+    foreach (array_keys($rooms) as $room_id) {
+      $parallel_blocks[$room_id] = array_fill(0, $blocks_per_slot, 0);
+    }
+    
+    // calculate number of parallel shifts in each timeslot for each room
+    foreach ($this->shifts as $shift) {
+      $room_id = $shift["RID"];
+      $shift_blocks = ($shift["end"] - $shift["start"]) / ShiftCalendarRenderer::MINUTES_PER_ROW;
+      $firstblock = floor(($shift["start"] - $first_block_start_time) / ShiftCalendarRenderer::MINUTES_PER_ROW);
+      for ($block = $firstblock; $block < $shift_blocks + $firstblock && $block < $blocks_per_slot; $block ++) {
+        $parallel_blocks[$room_id][$block] ++;
+      }
+    }
+    
+    return array_map('max', $parallel_blocks);
   }
 }
 
diff --git a/includes/view/ShiftsFilterRenderer.php b/includes/view/ShiftsFilterRenderer.php
index 94d53bb3..ff9302f7 100644
--- a/includes/view/ShiftsFilterRenderer.php
+++ b/includes/view/ShiftsFilterRenderer.php
@@ -18,10 +18,14 @@ class ShiftsFilterRenderer {
    */
   private $daySelectionEnabled = false;
 
+  /**
+   * Days that can be selected.
+   * Format Y-m-d
+   *
+   * @var string[]
+   */
   private $days = [];
 
-  private $event_config = null;
-
   public function __construct(ShiftsFilter $shiftsFilter) {
     $this->shiftsFilter = $shiftsFilter;
   }
@@ -31,14 +35,14 @@ class ShiftsFilterRenderer {
    *
    * @return Generated HTML
    */
-  public function render() {
+  public function render($link_base) {
     $toolbar = [];
     if ($this->daySelectionEnabled && ! empty($this->days)) {
       $today = date("Y-m-d");
       $selected_day = date("Y-m-d", $this->shiftsFilter->getStartTime());
       $day_dropdown_items = [];
       foreach ($this->days as $day) {
-        $day_dropdown_items[] = toolbar_item_link('', '', $day);
+        $day_dropdown_items[] = toolbar_item_link($link_base . '&shifts_filter_day=' . $day, '', $day);
       }
       $toolbar[] = toolbar_dropdown('', $selected_day, $day_dropdown_items, 'active');
     }
@@ -48,10 +52,9 @@ class ShiftsFilterRenderer {
   /**
    * Should the filter display a day selection.
    */
-  public function enableDaySelection($days, $event_config) {
+  public function enableDaySelection($days) {
     $this->daySelectionEnabled = true;
     $this->days = $days;
-    $this->event_config = $event_config;
   }
 
   /**