While the OP meant it the way he answered you, the way I see it used most often colloquially is that when someone or something does the heavy lifting especially in gaming, they are providing the bulk of the work. Like doing the heavy lifting in a team game equates to carrying the team, or saying a character does the heavy lifting instead of the player, means the character is overpowered and carrying the player (or vice versa).

Warm water is the waste product because it’s easier dump the water than to cool the water. Returning the warm water to a usable state is much more expensive at scale.

https://onepace.net/en

Can’t personally recommend but I know people that have used it. For me I just read manga if it’s the source material. Mainly because it’s faster usually.