Elk and Multi-Zone HVACs

Ultimately I would like to put each room on my second floor into its own HVAC Zone. Each room has varing usage, heating and cooling properties and climate control needs. I'll need to install a 5 zone HVAC controller that can be controlled by the M1G.

It seems that the M1XSP can only control thermostats and not Zone Controllers like the RCS ZCV6. I'll need to buy 5 M1XSPs and 5 TR16s (or TR40s) and a non-remote-controllable zone controller. This will limit me to two additional M1XSPs for future expansion. RCS only makes non-remote-controllable zone controllers upto 4 zones, but I found one at RetroZone.com that should work. Its the RobertShaw SlimZone Deluxe. This zone controller starts with 3 zones. Each expanders increase the capacity by 2 zones. From the documentation, it seems to work with any thermostat. Hopefully the 5 TR16s (or TR40s), 5 M1XSPs and SlimZone Deluxe will work for me.

This setup is overly complex and expensive. If Elk were to update the M1XSP to control the RCS ZCVx family of zone controllers, it would save alot of money and wiring. I could then get the RCS ZCV6 with 5 TS16s (or TS40s) and 1 M1XSP. I would then only have 1 wire from the ELK to the Zone Controller. This would be a cleaner and cheaper installation.

As it stands now, it seems that I'll have to use the SlimZone controller. Does anyone have any experience with this controller or RetroZone? Does anyone have any other controller recommendations or comments on my HVAC plans?
Have you looked at the AprilAire 8870 Thermostats? I haven't tried it, but I thought the ELK could talk to multiple 8870's through one M1XSP.
I don't think that you will need to buy more than one serial port expander. I am pretty sure that you can use 16 thermostats (of the same kind) with one serial port expander. Don't take my word for it. Call Martin at automated outlet. He is the MAN.

The good thing about RCS is that these are 4 wire and don't need separate power wires to these (worked in my favor) as the existing thermostat was 4 wire and I would have had to run an new wire If I chose HAI or any other make that requires power.

Let me know how this works out but I have heard folks use relays to control the dampers etc from elk and do away witht he zone controller. I would be very interested in what you find out as this is my next project after I get my garage working with elk.

The M1 can handle upto 16 Thermostats from one M1XSP. There is some variance according to which Thermostat you choose, from 4 on the HAI to 16 on RCS and Aprilaire.

When it gets past the Thermostat, I let the HVAC experts comment. Then "Black Magic" takes over. :)
I'm currently in the planning stages for my HVAC project. Since warmer weather is approaching, I probably won't get to start until fall, so I have plenty of time to do some research.

Doh! you guys are right, I only need one M1XSP for the RCS thermostats. Thanks for the quick replies!

I'm currently putting together a feature comparison of the available HVAC systems. Once it is fairly complete, I'll update this thread and share out the info.
Please do let us know what you figure out? I'm going to be in the same boat with some added twists.

I haven't done any ELK programming (yet) but, as someone mentioned, I'm wondering if you can use relay outputs from the ELK to at least handle some of the control functions? I could then use 2 RCS stats on the M1XSP.

I agree it would be great if ELK could support the RS485 interface on the RCS ZCV zone conrollers. RCS publishes the serial commands but I'm not sure what's involved to get the M1 to send and receive them?

For what it's worth, the RCS Commstar 48 home automation controller DOES talk to the ZCV zone controllers. The Commstar 48 is the same controller as the JDS Stargate so the JDS would work as well. But neither (yet?) supports Insteon which is a deal breaker for me.