Rental ADU (in-law) Utilities

[Jim G.]

Plan to build a new detached ADU (or so called in-laws unit) in my San Jose rental home. By city's rule, it is qualified for $700sf 1B/1B detached. I plan to put 1 shower, 1 dishwasher and 1 wash/dryer. Again by rule, both main unit and this ADU can be rented out separately. I want to separate utility bill, mainly electricity and gas, between main SFH and ADU. Heard it is very difficult to separate gas meter, option is to feed electricity only to ADU.

For HVAC, I think split type of A/C unit should be fine for both cooling and heating for 700sf space, run by electricity, given the mild CA bay area's weather.   For hot water, this is my concern... this where my dilemma is.  Is tankless electric water heater efficient enough to heat up the water for shower/dishwasher/laundry.  I believe people out there have done ADU should have some experience on this.  Let me know your thoughts.

[Adam Mayberry]

@Jim G. The Electric tankless is not very efficient. And hard to pass title 24. Even though electricity is actually more “green” code has not caught up with that yet.