How Much Value Will Building An ADU Provide?

[Matt H.]

I'm looking to build an ADU ("accessory dwelling unit") on my property in Denver and am wondering if anyone has any experience with the type of value it might add to the total property. I know they are notoriously difficult to appraise due to lack of comps. I'm not necessarily expecting a dollar for dollar return but am hesitant to spend $200k on a project to only have it add 50k in value. Any thoughts are greatly appreciated!