The Biden administration is tightening efficiency rules for water heaters, stoves and other appliances, and conservative politicians are dialing up their criticisms.
As discussed in section II.B.3, DOE is finalizing standards for all consumer water heaters, with the exception of gas-fired instantaneous water heaters, in this Final Rule.
So there has been no change to the rules for tankless heaters.
Per the actual rule:
So there has been no change to the rules for tankless heaters.
Is that because they were already efficient or because they can’t reasonably be made more sense efficient?
I would assume both. They transfer basically all the heat generated into the water and only heat when water is being used.