Thermostat recommendation


I'm trying to decide between two thermostat systems to interface with a ELK system.

I have 3 three t-stats on 2 heat pump units (1 regular - 1 with a 2 zone damper)

- AprilAire 8870 (with protocol converter, etc) about $850
- HAI RC series about $730

Anyone have experience with either of these?




I have some experience with the HAI RC series and RCS products. I actually like both and it’s hard to go wrong with either. I purchased both and eventually stuck with HAI RC-80B. The clean looks, blue back lighting, and overall feel eventually won me over. This of course is purely a personal preference. I’m currently controlling the RC-80B through HS via serial and it works great. I plan to eventually upgrade to an Elk M1G but that’s still a little ways off.


Senior Member
I have a HAI thermostat as well (the 80B I think it is) which I originally got because I expected to possibly get a HAI system.

Based on reviews here, the Elk was recommended and I saw the following on the elk site (which lets you integrate HAI for example to elk):

ELK-M1XSP Lighting/Thermostat Interface, Serial Port Expander
This is a "3 in 1" product. As a lighting interface, it adapts the M1 Gold Control to many brands of Lighting control products which use “serial" communications. i.e.,OnQ-ALC, PCS-UPB, EDT, CENTRALITE, VANTAGE, etc. As a thermostat interface, it adapts the M1 Control to HVAC Communicating Thermostats from companies such as:RCS, APRILAIRE, and HAI. As a serial port expander, it expands the RS-232 communication ports of the M1 for multiple connections to most any type of equipment that communicates using serial ASCII commands. i.e., Personal Computers and high end whole house subsystems such as: CRESTRON, AMX, etc. Jumpers on the M1XSP select the appropriate application, connection, and protocol. Best of all, the M1XSP operates from the 4-wire (RS-485) M1 Keypad data bus, allowing RS-232 ports to be located long distances from the control. The M1G (Gold) Cross Platform Control supports up to 7 M1XSPs.  The communications baud rate is adjustable from 300 to 38,400 baud. The unit comes complete with cable and a black surface mountable housing.

It is available at automatedoutlet and is about $64 though... good for me since I would like the control and already have one (of course it sounds like you can move the control to the PC and skip some of this from AccessX10's post , but another cost to factor in if that is what you anticipate doing (and I understand it correctly).


Senior Member
From least expensive to most expensive:

HAI - Least expensive but nice

RCS - Sexy brunette

Aprilaire - Really Sexy blonde



Spanky said:
From least expensive to most expensive:

HAI - Least expensive but nice

RCS - Sexy brunette

Aprilaire - Really Sexy blonde

Hmmm, not so sure I would want a "blond" controlling my HA thermostat!! ;)


New Member

I have installed three 8870 Thermostats to my M1. The setup I have, has one 8870 controling the second floor heating and AC, a second 9970 controls heating and AC for the first floor and the third only controls heating for the basement.

All fun, however, there are a couple of things you might want to think about before making the $$$$$ plung.

It is recommended and I did install:

(1) 8818 distribution panel, makes support and trouble shooting easier, or so they say, not to mention the panel has built in protection (fuses) to protect your very $$$$ thermostats.
(1) 8811 Protocol adapter
(1) ELK-M1XSP Lighting/Thermostat Interface , Serial Port Expander. which you need if you already have the db9 serial port used up as I did with the ELK-MK1XE.

Last but not least $$ (3) 8870.

So you really need to be aware of the complete picture, before you make your choice.

Now one thing that not many people look at is, what kind of support do you get when you NEED it? While not many people look at this, at some point you will need to place a call for support; you really don't want to go into a LONG que or send an email and WAIT... or dealing with BAD to non-existant support.

My experiance with APRILAIR, is that their support is OUTSTANDING.... They really know their stuff... that is what I need when I need it... P.S. did I mention that I got right through.

Also, again I have only worked with AprilAir.. Well made construction, quite flexible and they do get the attention of the AC and heating folks (WOW)...

Looks well that to me is personal, I liked the AprilAir, they appear simple yet nice, not a retro looking panel which you and all will see...

Hope this helps..