Both describe invisible effort, but they were coined for different arenas. Emotional labor is paid work under an employer's display rules; the mental load is the unpaid domestic work of remembering, planning and organising a household. The words get used interchangeably online, which blurs a useful distinction.
Side by side
Aspect
Emotional labor
The mental load
Where
At work
At home
Paid?
Yes
No
Rules set by
An employer
Nobody, explicitly
Named by
Hochschild, 1983
Later usage
What each one means
Emotional Labor
Emotional labor is the work of managing your own feelings, and the face you show, to produce the emotional display someone else expects — regardless of what you actually feel. Hochschild coined it for paid work and calls the private equivalent 'emotion work'; everyday usage has since stretched it to cover unpaid emotional labour at home, a broadening she has publicly objected to.