ELK Thermostats -- could it really be this easy?

politics123

Active Member
I have a 2 story house with two separate HVAC systems. ("Two zoned"). I'm ready to integrate them with my ELK, looked at the features, and figured that the HAI thermostats are a great option.

However, I feel like I'm missing something:
RC100B ~$150(for heat pump)
RC80B ~$150 (for gas furnace/CAC)

And, of course, an ELk M1XSP. So, here are my questions:

1) Is it really true that the HAI thermostats do NOT require an expensive controller? (eg: Aprilaire/RCS)
2) Do I only need one M1XSP for both thermostats? (I'm pretty sure I need a separate M1XSP for themostats and a second M1XSP for lighting, but I'm not sure whether I only need one M1XSP for both thermostats, or whether I need one-per-thermostat.)
3) What advantages do the expensive controller boxes give you over the HAI's?

Thanks!
 

Steve

Senior Member
The HAI stats require a dedicated 24V common to work properly which usually means 5 wires. Many homes are only wired with standard 4 wire t-stat wire, so keep that in mind. The HAI has everything in one. The RCS is simply broken down into 2 pieces, the 'brains' (controller) and a wall display unit. The advantage is you can locate the controller by the furnace and use standard wire to the wall display unit. You should only need 1 XSP for the stats.
 

Spanky

Senior Member
As Steve said,
With the HAI you will need wires for the HVAC control to the furnace air handler and 3 wires for the modified RS-232 to the HAI Thermostat. Normally you do not have the extra wires if replacing an existing thermostat and you will have to fish them to the thermostat.

RCS's advantage is that the thermostat control relays are separately located at the HVAC furnace and you can use the existing Thermostat wires to go to the display head where the old thermostat used to be located.

Aprilaire is similiar to the HAI with extra wires needed.

One M1XSP can drive 4 HAI thermostats, or 16 RCS or Aprilaire thermostats.
 

johnnynine

Active Member
Spanky said:
Aprilaire is similiar to the HAI with extra wires needed.
But doesn't the Aprilaire require an additional box at the HVAC unit as well? Or Can it be at the elk with just 16/5 going to the HVAC?
 

politics123

Active Member
Spanky said:
As Steve said,
With the HAI you will need wires for the HVAC control to the furnace air handler and 3 wires for the modified RS-232 to the HAI Thermostat. Normally you do not have the extra wires if replacing an existing thermostat and you will have to fish them to the thermostat.

RCS's advantage is that the thermostat control relays are separately located at the HVAC furnace and you can use the existing Thermostat wires to go to the display head where the old thermostat used to be located.

Aprilaire is similiar to the HAI with extra wires needed.

One M1XSP can drive 4 HAI thermostats, or 16 RCS or Aprilaire thermostats.
Thanks for the tip --

It's a new house, and during construction I added a few cat5 cables homerun from the builder-installed thermostats back to the wiring closet. So connecting back to the ELK should be easy.

The existing heat-pump thermostat has a "C" wire, which I assume is the common.

However, the gas/furnace only has 4-wire connected. I could probably ask someone to wire one of the "extra" wires to the 24v power, but can't the RC80B get power from just four-wires? The specs say that it can "power-steal" for retrofits. My question: is it fully functional when you use the power-steal method?

[Kicking-myself]
If I only I had the same foresight with the security system! I ran structured cable everywhere for network, video, and phone, but I didn't plan enough drops for security! I should have homerun occupancy sensors, fire detector cable, and all my 1st floor windows, instead of just the doors and a couple cables for alarm, keypads, etc. The extra wire would have been cheap, much less expensive than the fortune I'm going to spend on wireless products! [/Kicking-myself]
 

johnnynine

Active Member
WOW, what a price difference between HAI and Aprilaire!!! What would we get out of the Aprilaire to justify this?

2 Aprilaire Thermostats setup with ELK-M1:

$200 2 8870 thermostat (on sale now. normally $230)
$100 1 8818 distibution panel
$100 1 8811 protocol adapter
$80 1 ELK M1XSP Serial Port Expander
----
$680 TOTAL

2 HAI Thermostats setup with ELK-M1:

$125 2 HAI RC-80B Thermostat
$80 1 ELK M1XSP Serial Port Expander
----
$330 TOTAL


edit: typos
 

johnnynine

Active Member
AutomatedOutlet said:
I personally think that the HAI tstats look nicer than the Aprilaire too.
And you'll probably be getting a call from me this week or next for a couple of them and more. :)
 

Herdfan

Active Member
politics123 said:
wires? The specs say that it can "power-steal" for retrofits. My question: is it fully functional when you use the power-steal method?
Mine is running off 4 wires. The only difference I see is that the backlight doesn't stay on.
 

eufreka

Active Member
...One M1XSP can drive 4 HAI thermostats...

Just to clarify: One M1XSP will allow you to connect 2 SEPARATE HAI thermostats? That is, I have separate units for upstairs/downstairs (that's not technically "zones", is it?)

Each one drives a separate system.
 

DeLicious

Active Member
yes, just link them together on the 485 bus that they use to communicate... only one of them should be connected directly to the M1XSP

EDIT: I suppose you could hook them both the XSP, but I haven't tried it... i just connected my 2nd thermostat to the first.
 

wired-up

Member
Yes, I have 1 M1xsp controlling my upstairs and downstairs seperate units with seperate HAI thermostats. I am very pleased with the looks and function.
David
 

hult

Active Member
WOW, what a price difference between HAI and Aprilaire!!! What would we get out of the Aprilaire to justify this?

2 Aprilaire Thermostats setup with ELK-M1:

$200 2 8870 thermostat (on sale now. normally $230)
$100 1 8818 distibution panel
$100 1 8811 protocol adapter
$80 1 ELK M1XSP Serial Port Expander
----
$680 TOTAL

2 HAI Thermostats setup with ELK-M1:

$125 2 HAI RC-80B Thermostat
$80 1 ELK M1XSP Serial Port Expander
----
$330 TOTAL


edit: typos


Some points, with the caveat that that I have no experience whatever with the HAI or their t-stats but I have been using Enerzone Statnet devices (now Aprilaire) for almost 10 years. They have been supported by PC-based HA systems since before then.

1) The list price of the "$125" RC-80B is $184.50; Everyday price for the Aprilaire 8870 Communicating Thermostat is $199.95 at http://www.iautomate.com/8870.html

2) The RC-80B is a *single* stage thermostat whereas the Aprilaire 8870 (like its equivalent Enerzone predecessor) can handle *multi-stage* heating and cooling. So if you decide to upgrade from AC + gas to heat pump (+ gas or resistance electric) + AC, your RC-80 will become obsolete.

Ditto for adding active hot water heating. HAI devices that begin to be comparable in function to the 8870 are the RC-112B and RC-122B which are $217 at SH.

IOW, the 8870 provides the functionality of at least 4 different HAI models (including the RC-100B).

3) Also, you added into the cost of Aprilaire system a $100 8818 distibution panel which is completely unnecessary for a two or three or four thermostat 8870 system. IIRC, the 8818 is a passive 'device' that allows one to (dis)connect individual T-stats from the system for trouble-shooting. This is handy in an apartment complex with many (dozens?) thermostats but more of a nuisance (and expense) than it's worth for only 2-3 T-stats.

4) Also the Aprilaire uses RS-485 (the 8811 protocol adapter is a RS-232--> RS-485 adapter) exclusively. If you run into signal reliability issues with the RC-xxx's RS-232 comms, the factory fix is to buy a RC-202 RS-232 Serial Booster (list $100) or as I understand it, add an Omni panel ($) so as to be able to use RS-485 ? Whereas the Aprilaire obviates those problem by design, in advance, robustly by using RS-485.

5) The 8811 RS-232--> RS-485 adapter has the virtue that it electronically segments the RS-485 network. So shorts or other damage in one segment will not affect others. I dunno if that's the case with the HAI t-stats but it is another example of the robustness of the Enerzone/Aprilaire solution (IMO/E).

6) The Aprilaire/Enerzone/Statnet system allows addition of external and additional temperature sensors for averaging and humidity control without recourse to an Elk or Omni Pro or PC. I dunno what HAI t-stats _standalone_ capabilites are in this regard. If you have a heat pump, it becomes a significant issue. I want my HVAC systems to operate completely standalone is needed. It is not acceptable (to me) that it depend on an easily misprogrammed panel or PC.

7) The Aprilaire 8870, owing to its intrinsic flexibility and capabilities, is somewhat future-proofed. In any case in the context of the total cost to install and operate (!) two HVAC systems, the price difference (once corrected from what was posted) melts away.

Lastly, I like the Statnet/Aprilaire ASCII communication protocol enough to be contemplating adding other foreign gizmos to the network. Since the protocol can handle many devices, and existing devices will inherently ignore commands not addressed to them, one can build DIY devices (ADC, DAC, DIO, etc) that use that RS-485 network instead of reinventing the wheel and adding yet more hardware.

...Marc
 
Top