diff --git a/pkg/wix/build.ps1 b/pkg/wix/build.ps1
index 565b86b..3bc3a7e 100644
--- a/pkg/wix/build.ps1
+++ b/pkg/wix/build.ps1
@@ -1,5 +1,4 @@
 # TODO: This script should be replaced with wixproj and/or CPack.
-# TODO: Add Debug mode to override CompressionLevel with "none".
 
 # Sample command:
 # .\build.ps1 -Arch x64 -Version 0.4.0 -PackagePath "c:\tmp\zeal-0.4.0-windows-x64" -SignMsi
@@ -16,6 +15,7 @@ param(
     [Parameter(Mandatory=$True)]
     [string]$PackagePath,
 
+    [Switch]$DevBuild,
     [Switch]$SignMsi
 )
 
@@ -32,8 +32,12 @@ function CleanUp {
 
 Write-Output "Building $MsiFilename..."
 
+if ($DevBuild) {
+    $compressionLevelArg = '-dCompressionLevel="none"'
+}
+
 Write-Output "Running candle..."
-& candle.exe -nologo -pedantic -wx -arch "$Arch" -dAppVersion="$Version" -dAppPackageDir="$PackagePath" -o "$WixobjFilename" zeal.wxs
+& candle.exe -nologo -pedantic -wx -arch "$Arch" -dAppVersion="$Version" -dAppPackageDir="$PackagePath" $compressionLevelArg -o "$WixobjFilename" zeal.wxs
 if ($LastExitCode -ne 0) {
     CleanUp
     throw "candle failed with exit code $LastExitCode."
diff --git a/pkg/wix/zeal.wxs b/pkg/wix/zeal.wxs
index f7f916c..1f47651 100644
--- a/pkg/wix/zeal.wxs
+++ b/pkg/wix/zeal.wxs
@@ -8,6 +8,10 @@
     <?error AppPackageDir must be set ?>
 <?endif?>
 
+<?ifndef CompressionLevel ?>
+    <?define CompressionLevel="high" ?>
+<?endif?>
+
 <?define AppName="Zeal" ?>
 <?define AppManufacturer="Oleg Shparber" ?>
 <?define AppExeName="zeal.exe" ?>
@@ -39,7 +43,7 @@
               OnlyDetect="yes" Property="CURRENTVERSIONDETECTED" />
         </Upgrade>
 
-        <MediaTemplate CompressionLevel="high" EmbedCab="yes" />
+        <MediaTemplate CompressionLevel="$(var.CompressionLevel)" EmbedCab="yes" />
 
         <Icon Id="$(var.AppExeName)" SourceFile="$(var.AppPackageDir)\$(var.AppExeName)" />
         <Property Id="ARPPRODUCTICON" Value="$(var.AppExeName)" />