diff --git a/controllers/units_controller.php b/controllers/units_controller.php
index e6569b3..6e0e931 100644
--- a/controllers/units_controller.php
+++ b/controllers/units_controller.php
@@ -10,15 +10,21 @@ class UnitsController extends AppController {
     $this->all();
   }
 
+  function unavailable() {
+    $this->Unit->recursive = 0;
+    $this->set('units', $this->paginate(array($this->Unit->conditionUnavailable())));
+    $this->render('index');
+  }
+
   function vacant() {
     $this->Unit->recursive = 0;
-    $this->set('units', $this->paginate(array('Unit.status < ' . $this->Unit->occupiedEnumValue())));
+    $this->set('units', $this->paginate(array($this->Unit->conditionVacant())));
     $this->render('index');
   }
 
   function occupied() {
     $this->Unit->recursive = 0;
-    $this->set('units', $this->paginate(array('Unit.status >= ' . $this->Unit->occupiedEnumValue())));
+    $this->set('units', $this->paginate(array($this->Unit->conditionOccupied())));
     $this->render('index');
   }
 
diff --git a/models/unit.php b/models/unit.php
index 72c1af9..fb0b173 100644
--- a/models/unit.php
+++ b/models/unit.php
@@ -45,8 +45,35 @@ class Unit extends AppModel {
 		)
 	);
 
-	function occupiedEnumValue() {
-	  $enums = $this->getEnumValues('status');
-	  return $enums['OCCUPIED'];
+	function statusEnums() {
+	  static $status_enums;
+	  if (!isset($status_enums))
+	    $status_enums = $this->getEnumValues('status');
+	  return $status_enums;
 	}
+
+	function statusValue($enum) {
+	  $enums = $this->statusEnums();
+	  return $enums[$enum];
+	}
+
+	function occupiedEnumValue() {
+	  return statusValue('OCCUPIED');
+	}
+
+	function conditionOccupied() {
+	  return ('Unit.status >= ' . $this->statusValue('OCCUPIED'));
+	}
+
+	function conditionVacant() {
+	  return ('Unit.status BETWEEN ' .
+		  ($this->statusValue('UNAVAILABLE')+1) .
+		  ' AND ' .
+		  ($this->statusValue('OCCUPIED')-1));
+	}
+
+	function conditionUnavailable() {
+	  return ('Unit.status <= ' . $this->statusValue('UNAVAILABLE'));
+	}
+
 }