diff --git a/win32/installer/hexchat-x64.skel.iss b/win32/installer/hexchat-x64.skel.iss
index 799f224f..45598ec3 100644
--- a/win32/installer/hexchat-x64.skel.iss
+++ b/win32/installer/hexchat-x64.skel.iss
@@ -11,6 +11,7 @@ DefaultDirName={pf}\HexChat
 DefaultGroupName=HexChat
 DisableProgramGroupPage=yes
 SolidCompression=yes
+Compression=lzma2/ultra64
 SourceDir=..\rel
 OutputDir=..
 FlatComponentsList=no
diff --git a/win32/installer/hexchat-x86.skel.iss b/win32/installer/hexchat-x86.skel.iss
index 21b5efda..6bd31c33 100644
--- a/win32/installer/hexchat-x86.skel.iss
+++ b/win32/installer/hexchat-x86.skel.iss
@@ -11,6 +11,7 @@ DefaultDirName={pf}\HexChat
 DefaultGroupName=HexChat
 DisableProgramGroupPage=yes
 SolidCompression=yes
+Compression=lzma2/ultra64
 SourceDir=..\rel
 OutputDir=..
 FlatComponentsList=no