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.
@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.
@Adam Mayberry , thanks for the input. If this were the case, then gas water heater would be the only option regardless tanked or tankless. Is it possible if I put a submeter in the gas line to the ADU to calculate the usage of gas for ADU (not a separately gas meter which the cost will be ridiculously high)?
Originally posted by @Jim G. :
@Adam Mayberry, thanks for the input. If this were the case, then gas water heater would be the only option regardless tanked or tankless. Is it possible if I put a submeter in the gas line to the ADU to calculate the usage of gas for ADU (not a separately gas meter which the cost will be ridiculously high)?
Unfortunately when you have a separate address, which the City requires, to submeter the utilities PG&E requires separate meters.
You can always have "Utilities included" with couple hundred dollars extra to combat the use
Tankless gas water heater is the standard nowadays. Gas line extended to ADU is preferred for sure.
PG&E doesn't allow people to install gas submeters on their own (you can install an electricity submeter yourself for a few hundred dollars after filling out an easy online application). Unfortunately, gas as is viewed as dangerous and a more sensitive area for PG&E due to a recent accident I've heard, so they are pretty strict with it.
Bradford White makes a pretty decent electric tanked water heater if you can fit it in the adu. Bonus = no venting required. Pretty cheap to. Not sure about cali's energy code so you'd have to research that.