My ADU appraisal was very low

[Cesar Perini]

I have a 2b 1b house in bellflower CA. I extended it to a 3b 2b and built a 3b 2b ADU behind it. Now I own a 3b 2b house with an ADU that has 3b 2b. I'm refinancing the house now and my appraiser used comps of a SFH with only 3b 2b and NO ADU. That brought my appraisal value down a lot!! To me a home that doesn't have 6 beds and 4 baths isn't comparable to my house at all! Am I wrong for thinking this? Anyways, I disputed the original appraisal and the 2nd appraisal said they can't find comps with ADUs and can't use a comp that's a duplex so I have to keep the original appraisal. Any advise here or is this the way ADUs are appraised?

[Account Closed]

@Cesar Perini In the appraisal they only need 1 house that has an ADU to "bracket" your ADU feature, the rest can be normal single family. If they can't find any houses with an ADU, you likely over improved meaning the market did not have the need for a house with an ADU or there is no additional market reaction to people who have ADUs versus not. However, he can still do a single line on the grid to give value to the ADU unless he's arguing that it is an over improvement or similar utility as the house with 6 beds or whatever that he used. I would do my own due diligence by searching for a comp with an ADU. Keep in mind you can go back in time (up to 5 yrs) and out in distance into competing neighborhoods. If you can find comps that show the value add on, even just 1, then you have grounds to submit a reconsideration of value.