Aspell: how to change home dir globally?

aspell creates following files in my home: .aspell.en.prepl .aspell.en.pws How can I change the location globally, i.e. to $HOME/.cache/aspell ? I need to reference the $HOME environment variables in /etc/aspell.conf. I tried the following, but it does not seem to work:

home-dir $HOME/.cache/

How can I set home-dir globally, to be each users ~/.cache directory ? **CLARIFICATION** I don't run aspell manually. Applications such as Thunderbird run it themselves. Therefore, using a shell alias is not really a solution.