Many ways to achieve it. We do heat and AC control regularly and it works well. Although we usually do this at the thermostat level, if you are using an AC unit like cool master which has a driver directly to the air handler then that's how we would control it.

I tell people this when it comes to control of something like cool master. The Rti is simply another way to just turn the temp up and down, and see what the temp is. Take the Rti system and throw it out a window and the cool master will still work. So I don't see any reason controlling it via Rti has a negative impact on how your AC will perform.

If this dealer isn't comfortable with it find out why, maybe he had a bad experience with this product. If he doesn't like AC control in general I'd possibly suggest asking other local dealers. I hate to throw stones at other dealers, but AV control can be done well if done properly and their is no reason to steer customers away from it. With the Rti controlling it the home can run more efficiently. Many people these days have that goal in mind when redoing a home and for the dealers who know how to do it we have a great opportunity to sell systems that will make for more energy efficient homes and also open the door to other work such as security , lighting , theaters etc.