Refi of Primary home no longer deductible? What about house hack?

[Fausto Carosella]

Hey all,

So if I'm understanding this aspect of the new tax law, the mortgage interest is only deductible on ACQUISITION debt for your primary residence... correct? Meaning if I get into a house with a higher interest rate for whatever reason and a year or so down the road my credit situation is much better and I want to refi for a better rate that new mortgage interest will no longer be deductible? 

Now here's a slight caveat: What if I am house hacking and renting out two of three bedrooms?