Separate water heater for an ADU

[Jeff Cliff]

Hello,

Right after the purchase I had gotten water heater replaced for a property in California.

Now I am planning to convert upper floor into studio ADU. Now my question is, does ADU require separate water heater or can I use the same water heater for the main house?

Do I also need a separate HVAC system for ADU?

Thanks in advance for your response.

[Luke Marsh]

Hi @Jeff Cliff I think there are a couple issues with using a single water heater and HVAC. The first is possible tenant conflict, the hot/cold preferences for each tenant can cause conflict if they aren't able to control it within their unit. Some people prefer it warmer, while others prefer it cool. So I think you would need separate HVAC controls. The other issue is the capacity of your current water heater. Is it able to support the demand for both units simultaneously? Personally, I would also recommend a small on demand water heater for the ADU if the piping allows for it.