That money is best used for an emergency fund and to find your next property. 

Emergency life situations.

In the grand scheme of things, yes, you should eventually replace the windows so 1) They operate properly. 2) It doesn't turn away potential tenants or cause maintenance hassles when a new one moves in.3) Tenants have proper egress in case of an emergency (like fire).Now, windows are expensive, so you'll have to decide how much you're willing to spend, based on how much income the property is bringing in.

I am a first time homebuyer looking to house hack in Chicago and I have an almost 800 credit score, but I don't really have much saved up beyond my emergency fund for a down payment.

Does anyone of any suggestions on emerging areas that would be a great place to buy something in the range of 20-40 units?

Hi Dylan, I believe it may be best to get your credit and emergency fund ready before investing in a property.

Buy something in class B neighborhood or emerging class C neighborhood with higher cash upfront low leverage to ensure you have enough cashflow in worst case scenario and see how it performs.

We have a chuck of cash stores to keep us going for a while as emergency if needed.

I don’t have money saved up except an emergency savings fund.

But I'm also producing good cash flow, which I plan to first save and build a good 6-8 month emergency mortgage fund for both my rental property and my primary residence.