I'm considering adding a bedroom to each in the short term to pump up rent.

Additional problem - they have been renting the bedrooms out to dormers.  

Also we are building semi custom with very good subs so its not like the cheapo starter build to rent homes that are slapped together our houses are in great shape day one.. but there is always some cosmetics or something does not work right and OEM fix's it or the sub fix's it.. no big deal.

For the first question, since I am planning on renting out all units, would the ADUs require submetering?

@Cody Sears I can add $50/month on the rent if a unit has a washer/dryer.

The company offers what they call "attainably priced" apartments, arguing that their rents are lower than market rate.

The rent growth in that market is challenged to keep up with inflation.

We’re developing onto an existing residential property through the addition of an ADU we plan to rent medium term.

The returns I've seen as far as cash flow are decent, but what attracted me are the typical long term leases with rent escalations every year.

STR regulations are a big consideration before you make any big capital improvements specifically for short term stays, also running your numbers and making sure that your area offers consistent returns above what you'd get renting it long-term.