Hi There,
Apologies for the late reply, I hope the issue would be fixed by now.
The minimum hard disk space that Acrobat Reader requires is 380 MB. Please refer to the help article in the link: Adobe Acrobat Reader DC system requirements to check the minimum system requirements.
Adding on to the suggestion by "try67"
Windows Installer database might be the reason for 962MB of space being utilized as it keeps a complete copy of the installer so that you can repair later. Each update will add a lot more to it. If you get a lot of updates, that will increase the disk size being utilized.
You may try to uninstall and reinstall with one latest update that might fix the issue for you.
I hope this will help, Do let us know with the results.
Regards,
Amal