I am using a HELOC on my first duplex to help supplement me on the second property.

There are also supplement loan features built into commercial financing that allow cash out once the property has been re-positioned.The most important factor is the profit per property...profit per unit is not as relevant. 

If you've got steam, things can get complicated, however you might be able to clean up your living area by removing the radiators and adding forced air.High velocity is a nice option if you have a finished basement or finished attic / 3rd floor.Finally, the mini-splits can be great to supplement heating and add cooling.

@Austin Janiszewski if your current primary (Property A) is renovated and will generate positive cash flow after renting, consider this scenario:Instead of selling, utilize Property A as a source of supplemental income to offset the higher interest rate environment.

We own a duplex rental property here in Virginia Beach and are mostly of the buy/hold mentality to supplement eventual retirement income in 6 years.

They planned to buy a large apartment house and operate it through a property manager, providing them a nice cash flow to supplement their other retirement income.

Typically they will be able to qualify 75% of the rent as supplemental income.

I'm also supplementing that with a home warranty.  

We will need supplemental income during our retirement since we are not going to earn Social security in the beginning.

In 2016 I was involved in around 5 flips and 2017 10, now I am currently looking into buy and hold to give me a steady passive income and flipping to supplement as I go.