Rated 4 out of 5 stars
For some reason, pinned tabs seem to reload instantly after "unloading" them.This review is for a previous version of the add-on (1.5). This user has a previous review of this add-on.
"browser.sessionstore.restore_pinned_tabs_on_demand" is your friend in about:config.
Please see detailed instructions on https://support.mozilla.org/en-US/questions/940656#answer-377837
By the way, I'm planning to add a checkbox in options for this pref.