Changing out Electric Heater, does AC needs to be replaced too?

[Crystal Dundas]

Hi folks,

A few weeks back, I decided, at the advice of all of you beautiful people to convert my rental from electric to gas heating.  I just received the quote and the hvac guy is saying I have to change out my AC unit as well.  There is nothing wrong with the unit that I have.  Do I really need to do both?  If so, I may very well just leave the unit without central air.  I'm in Philadelphia so we get very few days that are so hot that AC is a must have.  and the house has ceiling fans throughout.

Let me know your thoughts.