It's what I use for my rental portfolio, and they've got a great platform / app that allows you to see everything.

@Benjamin Schlais you can general market and advertise on any and all platforms, it would would simply be up to you to direct your applicants or leads to the system they will use once approved. 

I am considering these types of homes as well......with window units. 

You don't want towels nailed to the window frame.

@Elton John - I'd go to Star Hardware in Hartford and ask them who buys a lot of windows from them and see if they can give you a phone number.  

Several times a year I am am sending out a text message to all tenants (freeze warnings, inspection reminder, etc) I am looking for an online platform that has a good app as well as a website that I can use to do those tasks.

I am asking because we spend an awful lot of money on REI platforms and not one of them has everything I need. 

In other words, where is the work happening most often (e.g., property-management systems, lead platforms, CRMs)?

Insulation/Windows: What is the average payback period you see on high-efficiency windows and insulation vs. the cost, especially for rental properties?

Any other platforms that are recommended.