Is there a way to hide hotbars when not in combat?

[Ghastly]

Sort of. If you're looking for it to be completely automatic, I don't think there is. But you can make macros to hide (well, toggle really) pretty much any hud element, including hotbars.

For example

/hotbar display 1

putting this in a macro will toggle displaying hotbar 1 on or off. Add the rest of the hotbars you want, and any other hud elements you might not want on all the time.

Thank you so much this worked perfectly, such an amazing solution