diff --git a/apps/essimporter/converter.hpp b/apps/essimporter/converter.hpp
index 550b7c0ae..f364e166c 100644
--- a/apps/essimporter/converter.hpp
+++ b/apps/essimporter/converter.hpp
@@ -398,7 +398,7 @@ public:
     virtual void read(ESM::ESMReader &esm)
     {
         std::string itemid = esm.getHNString("NAME");
-        Misc::StringUtils::toLower(itemid);
+        Misc::StringUtils::lowerCaseInPlace(itemid);
 
         while (esm.isNextSub("FNAM") || esm.isNextSub("ONAM"))
         {
diff --git a/apps/mwiniimporter/importer.cpp b/apps/mwiniimporter/importer.cpp
index 251889e28..5fdc3cbf5 100644
--- a/apps/mwiniimporter/importer.cpp
+++ b/apps/mwiniimporter/importer.cpp
@@ -846,7 +846,7 @@ void MwIniImporter::importGameFiles(multistrmap &cfg, const multistrmap &ini, co
 
         for(std::vector<std::string>::const_iterator entry = it->second.begin(); entry!=it->second.end(); ++entry) {
             std::string filetype(entry->substr(entry->length()-3));
-            Misc::StringUtils::toLower(filetype);
+            Misc::StringUtils::lowerCaseInPlace(filetype);
 
             if(filetype.compare("esm") == 0 || filetype.compare("esp") == 0) {
                 boost::filesystem::path filepath(gameFilesDir);
diff --git a/apps/opencs/model/world/commanddispatcher.cpp b/apps/opencs/model/world/commanddispatcher.cpp
index 0bef1bb4e..a1fc980eb 100644
--- a/apps/opencs/model/world/commanddispatcher.cpp
+++ b/apps/opencs/model/world/commanddispatcher.cpp
@@ -93,7 +93,7 @@ void CSMWorld::CommandDispatcher::setEditLock (bool locked)
 void CSMWorld::CommandDispatcher::setSelection (const std::vector<std::string>& selection)
 {
     mSelection = selection;
-    std::for_each (mSelection.begin(), mSelection.end(), Misc::StringUtils::toLowerStr);
+    std::for_each (mSelection.begin(), mSelection.end(), Misc::StringUtils::lowerCaseInPlace);
     std::sort (mSelection.begin(), mSelection.end());
 }
 
diff --git a/apps/opencs/model/world/regionmap.cpp b/apps/opencs/model/world/regionmap.cpp
index 17831c2ac..6dbbac97f 100644
--- a/apps/opencs/model/world/regionmap.cpp
+++ b/apps/opencs/model/world/regionmap.cpp
@@ -168,7 +168,7 @@ void CSMWorld::RegionMap::updateRegions (const std::vector<std::string>& regions
 {
     std::vector<std::string> regions2 (regions);
 
-    std::for_each (regions2.begin(), regions2.end(), Misc::StringUtils::toLowerStr);
+    std::for_each (regions2.begin(), regions2.end(), Misc::StringUtils::lowerCaseInPlace);
     std::sort (regions2.begin(), regions2.end());
 
     for (std::map<CellCoordinates, CellDescription>::const_iterator iter (mMap.begin());
diff --git a/apps/opencs/model/world/scriptcontext.cpp b/apps/opencs/model/world/scriptcontext.cpp
index 33025bd1c..344ae322e 100644
--- a/apps/opencs/model/world/scriptcontext.cpp
+++ b/apps/opencs/model/world/scriptcontext.cpp
@@ -93,7 +93,7 @@ bool CSMWorld::ScriptContext::isId (const std::string& name) const
     {
         mIds = mData.getIds();
 
-        std::for_each (mIds.begin(), mIds.end(), &Misc::StringUtils::toLowerStr);
+        std::for_each (mIds.begin(), mIds.end(), &Misc::StringUtils::lowerCaseInPlace);
         std::sort (mIds.begin(), mIds.end());
 
         mIdsUpdated = true;
diff --git a/apps/openmw/mwclass/container.cpp b/apps/openmw/mwclass/container.cpp
index 6c44c97e2..bfdcc23c1 100644
--- a/apps/openmw/mwclass/container.cpp
+++ b/apps/openmw/mwclass/container.cpp
@@ -148,11 +148,11 @@ namespace MWClass
 
         // make key id lowercase
         std::string keyId = ptr.getCellRef().getKey();
-        Misc::StringUtils::toLower(keyId);
+        Misc::StringUtils::lowerCaseInPlace(keyId);
         for (MWWorld::ContainerStoreIterator it = invStore.begin(); it != invStore.end(); ++it)
         {
             std::string refId = it->getCellRef().getRefId();
-            Misc::StringUtils::toLower(refId);
+            Misc::StringUtils::lowerCaseInPlace(refId);
             if (refId == keyId)
             {
                 hasKey = true;
diff --git a/apps/openmw/mwclass/door.cpp b/apps/openmw/mwclass/door.cpp
index 6fee79ddf..56c5e655f 100644
--- a/apps/openmw/mwclass/door.cpp
+++ b/apps/openmw/mwclass/door.cpp
@@ -117,11 +117,11 @@ namespace MWClass
 
         // make key id lowercase
         std::string keyId = ptr.getCellRef().getKey();
-        Misc::StringUtils::toLower(keyId);
+        Misc::StringUtils::lowerCaseInPlace(keyId);
         for (MWWorld::ContainerStoreIterator it = invStore.begin(); it != invStore.end(); ++it)
         {
             std::string refId = it->getCellRef().getRefId();
-            Misc::StringUtils::toLower(refId);
+            Misc::StringUtils::lowerCaseInPlace(refId);
             if (refId == keyId)
             {
                 hasKey = true;
diff --git a/apps/openmw/mwgui/formatting.cpp b/apps/openmw/mwgui/formatting.cpp
index 6adef5eeb..6a8145e97 100644
--- a/apps/openmw/mwgui/formatting.cpp
+++ b/apps/openmw/mwgui/formatting.cpp
@@ -129,7 +129,7 @@ namespace MWGui
             size_t tagNameEndPos = tag.find(' ');
             mAttributes.clear();
             mTag = tag.substr(0, tagNameEndPos);
-            Misc::StringUtils::toLower(mTag);
+            Misc::StringUtils::lowerCaseInPlace(mTag);
             if (mTag.empty())
                 return;
 
@@ -151,7 +151,7 @@ namespace MWGui
                     return;
 
                 std::string key = tag.substr(0, sepPos);
-                Misc::StringUtils::toLower(key);
+                Misc::StringUtils::lowerCaseInPlace(key);
                 tag.erase(0, sepPos+1);
 
                 std::string value;
diff --git a/apps/openmw/mwgui/itemmodel.cpp b/apps/openmw/mwgui/itemmodel.cpp
index a1e36bce6..2c382f3cf 100644
--- a/apps/openmw/mwgui/itemmodel.cpp
+++ b/apps/openmw/mwgui/itemmodel.cpp
@@ -35,7 +35,7 @@ namespace MWGui
             {
                 const ESM::GameSetting &currentSetting = *currentIteration;
                 std::string currentGMSTID = currentSetting.mId;
-                Misc::StringUtils::toLower(currentGMSTID);
+                Misc::StringUtils::lowerCaseInPlace(currentGMSTID);
 
                 // Don't bother checking this GMST if it's not a sMagicBound* one.
                 const std::string& toFind = "smagicbound";
@@ -44,7 +44,7 @@ namespace MWGui
 
                 // All sMagicBound* GMST's should be of type string
                 std::string currentGMSTValue = currentSetting.getString();
-                Misc::StringUtils::toLower(currentGMSTValue);
+                Misc::StringUtils::lowerCaseInPlace(currentGMSTValue);
 
                 boundItemIDCache.insert(currentGMSTValue);
             }
@@ -52,7 +52,7 @@ namespace MWGui
 
         // Perform bound item check and assign the Flag_Bound bit if it passes
         std::string tempItemID = base.getCellRef().getRefId();
-        Misc::StringUtils::toLower(tempItemID);
+        Misc::StringUtils::lowerCaseInPlace(tempItemID);
 
         if (boundItemIDCache.count(tempItemID) != 0)
             mFlags |= Flag_Bound;
diff --git a/apps/openmw/mwmechanics/activespells.cpp b/apps/openmw/mwmechanics/activespells.cpp
index 7068310a0..6a247622c 100644
--- a/apps/openmw/mwmechanics/activespells.cpp
+++ b/apps/openmw/mwmechanics/activespells.cpp
@@ -132,15 +132,11 @@ namespace MWMechanics
         return scaledDuration-usedUp;
     }
 
-    bool ActiveSpells::isSpellActive(std::string id) const
+    bool ActiveSpells::isSpellActive(const std::string& id) const
     {
-        Misc::StringUtils::toLower(id);
         for (TContainer::iterator iter = mSpells.begin(); iter != mSpells.end(); ++iter)
         {
-            std::string left = iter->first;
-            Misc::StringUtils::toLower(left);
-
-            if (iter->first == id)
+            if (Misc::StringUtils::ciEqual(iter->first, id))
                 return true;
         }
         return false;
diff --git a/apps/openmw/mwmechanics/activespells.hpp b/apps/openmw/mwmechanics/activespells.hpp
index 2a4d75d40..3842ee61c 100644
--- a/apps/openmw/mwmechanics/activespells.hpp
+++ b/apps/openmw/mwmechanics/activespells.hpp
@@ -97,7 +97,7 @@ namespace MWMechanics
             /// Remove all spells
             void clear();
 
-            bool isSpellActive (std::string id) const;
+            bool isSpellActive (const std::string& id) const;
             ///< case insensitive
 
             const MagicEffects& getMagicEffects() const;
diff --git a/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp b/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp
index 68bea02b0..ba958df10 100644
--- a/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp
+++ b/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp
@@ -604,7 +604,7 @@ namespace MWMechanics
         int rank = 0;
         std::string npcFaction = ptr.getClass().getPrimaryFaction(ptr);
 
-        Misc::StringUtils::toLower(npcFaction);
+        Misc::StringUtils::lowerCaseInPlace(npcFaction);
 
         if (playerStats.getFactionRanks().find(npcFaction) != playerStats.getFactionRanks().end())
         {
@@ -1042,7 +1042,7 @@ namespace MWMechanics
             owner.first = ownerCellRef->getFaction();
             owner.second = true;
         }
-        Misc::StringUtils::toLower(owner.first);
+        Misc::StringUtils::lowerCaseInPlace(owner.first);
 
         if (!Misc::StringUtils::ciEqual(item.getCellRef().getRefId(), MWWorld::ContainerStore::sGoldId))
             mStolenItems[Misc::StringUtils::lowerCase(item.getClass().getId(item))][owner] += count;
diff --git a/apps/openmw/mwrender/animation.cpp b/apps/openmw/mwrender/animation.cpp
index ecfb2df14..214e7f221 100644
--- a/apps/openmw/mwrender/animation.cpp
+++ b/apps/openmw/mwrender/animation.cpp
@@ -390,7 +390,7 @@ namespace MWRender
     void Animation::addAnimSource(const std::string &model)
     {
         std::string kfname = model;
-        Misc::StringUtils::toLower(kfname);
+        Misc::StringUtils::lowerCaseInPlace(kfname);
 
         if(kfname.size() > 4 && kfname.compare(kfname.size()-4, 4, ".nif") == 0)
             kfname.replace(kfname.size()-4, 4, ".kf");
diff --git a/apps/openmw/mwscript/cellextensions.cpp b/apps/openmw/mwscript/cellextensions.cpp
index b6f7229e0..513c1cc42 100644
--- a/apps/openmw/mwscript/cellextensions.cpp
+++ b/apps/openmw/mwscript/cellextensions.cpp
@@ -123,7 +123,7 @@ namespace MWScript
                     const MWWorld::CellStore *cell = MWMechanics::getPlayer().getCell();
 
                     std::string current = MWBase::Environment::get().getWorld()->getCellName(cell);
-                    Misc::StringUtils::toLower(current);
+                    Misc::StringUtils::lowerCaseInPlace(current);
 
                     bool match = current.length()>=name.length() &&
                         current.substr (0, name.length())==name;
diff --git a/apps/openmw/mwscript/guiextensions.cpp b/apps/openmw/mwscript/guiextensions.cpp
index 397e0cac5..254da56d6 100644
--- a/apps/openmw/mwscript/guiextensions.cpp
+++ b/apps/openmw/mwscript/guiextensions.cpp
@@ -116,7 +116,7 @@ namespace MWScript
             virtual void execute (Interpreter::Runtime& runtime)
             {
                 std::string cell = (runtime.getStringLiteral (runtime[0].mInteger));
-                ::Misc::StringUtils::toLower(cell);
+                ::Misc::StringUtils::lowerCaseInPlace(cell);
                 runtime.pop();
 
                 // "Will match complete or partial cells, so ShowMap, "Vivec" will show cells Vivec and Vivec, Fred's House as well."
@@ -129,7 +129,7 @@ namespace MWScript
                 for (; it != cells.extEnd(); ++it)
                 {
                     std::string name = it->mName;
-                    ::Misc::StringUtils::toLower(name);
+                    ::Misc::StringUtils::lowerCaseInPlace(name);
                     if (name.find(cell) != std::string::npos)
                         MWBase::Environment::get().getWindowManager()->addVisitedLocation (
                             it->mName,
diff --git a/apps/openmw/mwscript/statsextensions.cpp b/apps/openmw/mwscript/statsextensions.cpp
index e4ad71875..3996dd80b 100644
--- a/apps/openmw/mwscript/statsextensions.cpp
+++ b/apps/openmw/mwscript/statsextensions.cpp
@@ -543,7 +543,7 @@ namespace MWScript
                         factionID = runtime.getStringLiteral (runtime[0].mInteger);
                         runtime.pop();
                     }
-                    ::Misc::StringUtils::toLower(factionID);
+                    ::Misc::StringUtils::lowerCaseInPlace(factionID);
                     // Make sure this faction exists
                     MWBase::Environment::get().getWorld()->getStore().get<ESM::Faction>().find(factionID);
 
@@ -575,7 +575,7 @@ namespace MWScript
                         factionID = runtime.getStringLiteral (runtime[0].mInteger);
                         runtime.pop();
                     }
-                    ::Misc::StringUtils::toLower(factionID);
+                    ::Misc::StringUtils::lowerCaseInPlace(factionID);
                     // Make sure this faction exists
                     MWBase::Environment::get().getWorld()->getStore().get<ESM::Faction>().find(factionID);
 
@@ -614,7 +614,7 @@ namespace MWScript
                         factionID = runtime.getStringLiteral (runtime[0].mInteger);
                         runtime.pop();
                     }
-                    ::Misc::StringUtils::toLower(factionID);
+                    ::Misc::StringUtils::lowerCaseInPlace(factionID);
                     // Make sure this faction exists
                     MWBase::Environment::get().getWorld()->getStore().get<ESM::Faction>().find(factionID);
 
@@ -645,7 +645,7 @@ namespace MWScript
                     {
                         factionID = ptr.getClass().getPrimaryFaction(ptr);
                     }
-                    ::Misc::StringUtils::toLower(factionID);
+                    ::Misc::StringUtils::lowerCaseInPlace(factionID);
                     // Make sure this faction exists
                     MWBase::Environment::get().getWorld()->getStore().get<ESM::Faction>().find(factionID);
 
@@ -756,7 +756,7 @@ namespace MWScript
                     if (factionId.empty())
                         throw std::runtime_error ("failed to determine faction");
 
-                    ::Misc::StringUtils::toLower (factionId);
+                    ::Misc::StringUtils::lowerCaseInPlace (factionId);
 
                     MWWorld::Ptr player = MWMechanics::getPlayer();
                     runtime.push (
@@ -791,7 +791,7 @@ namespace MWScript
                     if (factionId.empty())
                         throw std::runtime_error ("failed to determine faction");
 
-                    ::Misc::StringUtils::toLower (factionId);
+                    ::Misc::StringUtils::lowerCaseInPlace (factionId);
 
                     MWWorld::Ptr player = MWMechanics::getPlayer();
                     player.getClass().getNpcStats (player).setFactionReputation (factionId, value);
@@ -825,7 +825,7 @@ namespace MWScript
                     if (factionId.empty())
                         throw std::runtime_error ("failed to determine faction");
 
-                    ::Misc::StringUtils::toLower (factionId);
+                    ::Misc::StringUtils::lowerCaseInPlace (factionId);
 
                     MWWorld::Ptr player = MWMechanics::getPlayer();
                     player.getClass().getNpcStats (player).setFactionReputation (factionId,
@@ -870,11 +870,11 @@ namespace MWScript
                     MWWorld::Ptr ptr = R()(runtime);
 
                     std::string race = runtime.getStringLiteral(runtime[0].mInteger);
-                    ::Misc::StringUtils::toLower(race);
+                    ::Misc::StringUtils::lowerCaseInPlace(race);
                     runtime.pop();
 
                     std::string npcRace = ptr.get<ESM::NPC>()->mBase->mRace;
-                    ::Misc::StringUtils::toLower(npcRace);
+                    ::Misc::StringUtils::lowerCaseInPlace(npcRace);
 
                     runtime.push (npcRace == race);
             }
@@ -911,7 +911,7 @@ namespace MWScript
                     {
                         factionID = ptr.getClass().getPrimaryFaction(ptr);
                     }
-                    ::Misc::StringUtils::toLower(factionID);
+                    ::Misc::StringUtils::lowerCaseInPlace(factionID);
                     MWWorld::Ptr player = MWMechanics::getPlayer();
                     if(factionID!="")
                     {
diff --git a/apps/openmw/mwworld/cellstore.cpp b/apps/openmw/mwworld/cellstore.cpp
index 5832a6727..029dac22d 100644
--- a/apps/openmw/mwworld/cellstore.cpp
+++ b/apps/openmw/mwworld/cellstore.cpp
@@ -472,7 +472,7 @@ namespace MWWorld
 
     void CellStore::loadRef (ESM::CellRef& ref, bool deleted, const ESMStore& store)
     {
-        Misc::StringUtils::toLower (ref.mRefID);
+        Misc::StringUtils::lowerCaseInPlace (ref.mRefID);
 
         switch (store.find (ref.mRefID))
         {
diff --git a/apps/openmw/mwworld/globals.cpp b/apps/openmw/mwworld/globals.cpp
index 4a406613d..acc06b28a 100644
--- a/apps/openmw/mwworld/globals.cpp
+++ b/apps/openmw/mwworld/globals.cpp
@@ -96,7 +96,7 @@ namespace MWWorld
             // This readRecord() method is used when reading a saved game.
             // Deleted globals can't appear there, so isDeleted will be ignored here.
             global.load(reader, isDeleted);
-            Misc::StringUtils::toLower(global.mId);
+            Misc::StringUtils::lowerCaseInPlace(global.mId);
 
             Collection::iterator iter = mVariables.find (global.mId);
             if (iter!=mVariables.end())
diff --git a/apps/openmw/mwworld/store.cpp b/apps/openmw/mwworld/store.cpp
index 3d23f3da4..d1ba0ef0b 100644
--- a/apps/openmw/mwworld/store.cpp
+++ b/apps/openmw/mwworld/store.cpp
@@ -190,7 +190,7 @@ namespace MWWorld
         bool isDeleted = false;
 
         record.load(esm, isDeleted);
-        Misc::StringUtils::toLower(record.mId);
+        Misc::StringUtils::lowerCaseInPlace(record.mId);
 
         std::pair<typename Static::iterator, bool> inserted = mStatic.insert(std::make_pair(record.mId, record));
         if (inserted.second)
diff --git a/components/misc/resourcehelpers.cpp b/components/misc/resourcehelpers.cpp
index 0c2635752..6fe13abf3 100644
--- a/components/misc/resourcehelpers.cpp
+++ b/components/misc/resourcehelpers.cpp
@@ -51,7 +51,7 @@ std::string Misc::ResourceHelpers::correctResourcePath(const std::string &topLev
     std::string prefix2 = topLevelDirectory + '/';
 
     std::string correctedPath = resPath;
-    Misc::StringUtils::toLower(correctedPath);
+    Misc::StringUtils::lowerCaseInPlace(correctedPath);
 
     // Apparently, leading separators are allowed
     while (correctedPath.size() && (correctedPath[0] == '/' || correctedPath[0] == '\\'))
diff --git a/components/misc/stringops.hpp b/components/misc/stringops.hpp
index 2fd997285..2723527f1 100644
--- a/components/misc/stringops.hpp
+++ b/components/misc/stringops.hpp
@@ -94,21 +94,16 @@ public:
     }
 
     /// Transforms input string to lower case w/o copy
-    static void toLower(std::string &inout) {
+    static void lowerCaseInPlace(std::string &inout) {
         for (unsigned int i=0; i<inout.size(); ++i)
             inout[i] = toLower(inout[i]);
     }
 
-    static void toLowerStr(std::string &inout)
-    {
-        toLower(inout);
-    }
-
     /// Returns lower case copy of input string
     static std::string lowerCase(const std::string &in)
     {
         std::string out = in;
-        toLower(out);
+        lowerCaseInPlace(out);
         return out;
     }
 };