I used WiX 3.7 to write a bootstrapper which installs .net 4.5 first and then my application's MSI:
<Chain>
  <PackageGroupRef Id="NetFx45Redist"/>
  <MsiPackage Id="MainAppPackage"
              After="NetFx45Redist"
              SourceFile="..\bin\Debug\MyApp.msi"/>
</Chain>
The WiX documentation says that NetFx45Redist is a standalone setup while the NetFx45Web is a web setup. After I built the bootstrapper with Id set to NetFx45Redist it had the same size compared to when I build it with NetFx45Web Id specified. I was curious so I downloaded the WiX sources (v3.7). I was surprised to see that there was little difference between the two PackageGroup elements.
The DownloadUrl for NetFx45Web is http://go.microsoft.com/fwlink/?LinkId=225704, while the one for NetFx45Redist is http://go.microsoft.com/fwlink/?LinkId=225702. According to the RemotePayload\@Size attribute NetFx45Web is 1005568 bytes and NetFx45Redist is 50352408 bytes.
I expected that NetFx45Redist will include the .net 4.5 setup in my bootstrapper and no download will be required. I see that's wrong. Which PackageGroup should I use then and what is the difference between the 2 downloaded .net 4.5 installations?