I am hoping someone with professional or personal experience in this area might have some insight. We are in contract on a triplex investment property and are planning on using HELOC funds from our former primary residence (now a rental) for the down payment. Will the interest we pay on the HELOC be deductible as a rental expense against the new investment property rental business? To possibly make matters more complicated, one of the units in the triplex will be a long-term rental, and two of the units will be for a short-term rental business (Airbnb). Thanks!