To me this is a huge increase, I know we should count on taxes to increase, but I was thinking in the neighborhood of maybe a $500 increase occasionally?

You are counting on two properties to keep you going, since you didn't mention any other investments.

Someone mentioned maybe if some crazy appreciation was involved, but I'll tell you with the market we are in right now, I would definitely not count on ANY appreciation. 

Generally you don't have much to lose when you are just starting, so it's not as important to provide that kind of coverage early on - especially when every penny counts.

@Raymond Garcia count the number of rooms. 

Thanks,Nate I'm not a lawyer and this is not legal advice, but there's a broad consensus that they aren't counting the number of total awake hours in the home, they are counting the number of nights your head is asleep on a pillow in that home, and >50% makes it a primary residence. 4 out of 7 nights a week would seem to tick that box.

Is it at least a house that can be counted on to appreciate and offer a long term return, instead?

Keep it mind only time on your owned properties counts (no research on future properties).

I recently did a count on the leads; about 80% of the leads came from Zillow. 

@Sweeney Mae Montinola - If you have a lease signed then they will likely count it.