I was reading the posts on electric heaters yesterday. When winterizing, I blow out my lines and pour antifreeze into traps an toilet. We live in upstate S Carolina and don't usually need more then ...
No one on a forum can guarantee, that your chord being slightly warm is OK. Your idea of slightly warm may be different than mine.
I would not worry about my chord being, my version, of slightly warm, right at the plug end. It does not take a lot of watts to make the plug end slightly warm.