ISY + Thermostat ... Fundamental Questions

[mikek]

I have some questions about the interaction between an ISY and a Z-Wave or Insteon thermostat.

• Does the ISY only send down a command only when there is need (a setpoint change, for example) or is communication constant?
• Does the ISY receive any feedback from the thermostat indicating that the programmed setpoint change was accepted?
• What happens when communication fails? Does the thermostat retain its "last" settings indefinitely?
• What happens when communication is restored? Does the thermostat get updated to the current program setpoint or does it wait until the next time- or event-based step in the program?
• Are the Z-Wave and Insteon thermostats typically programmable locally, or is a controller required?

Thanks very much!

[cam]

Hi Mike,

 

I can speak for the Insteon Thermos... the ISY actively listens for all Insteon events so if you change the temp on the wall ISY knows it. Likewise if you alter the temp via the ISY that feedback from the thermostat comes back to the ISY so you know it happened. The thermo will keep its last state regardless if the ISY communication is broken. Once com is restored the ISY will fetch updates (I believe). Insteon can be programmed locally or remotely... looks like any other HVAC control.

 

Hope that helps

 

 

Sent from my iPhone using Tapatalk

[ScottAvery]

If you are using the ISY for automation and are comfortable with it, you may be better served doing all your scheduling inside the ISY and leave the thermostat unprogrammed.  ISY can do everything the thermostat can, and more.

[mikek]

Hi Mike,

 

I can speak for the Insteon Thermos... the ISY actively listens for all Insteon events so if you change the temp on the wall ISY knows it. Likewise if you alter the temp via the ISY that feedback from the thermostat comes back to the ISY so you know it happened. The thermo will keep its last state regardless if the ISY communication is broken. Once com is restored the ISY will fetch updates (I believe). Insteon can be programmed locally or remotely... looks like any other HVAC control.

 

Hope that helps

 

 

Sent from my iPhone using Tapatalk

Thank you.

[mikek]

If you are using the ISY for automation and are comfortable with it, you may be better served doing all your scheduling inside the ISY and leave the thermostat unprogrammed.  ISY can do everything the thermostat can, and more.

Thanks, Scott. I'm just getting started with the ISY, and want to add a thermostat. Trying to understand what happens if I have issues and be sure that I can use it as a stand-alone unit (including local programming).

[stusviews]

Except for generating traffic, the ISY will do nothing whenever any setting on the thermostat is changed unless the ISY programmed to respond. Loss of communication between the ISY and the thermostat will do nothing unless the ISY is programmed or scheduled to do something during the loss period. Neither will automatically "catch-up."

 

If the thermostat loses power, it will remain in the last state until and/or unless there's a new schedule or program command that occurs after power is resumed.

 

All programmable thermostats are programmable locally. Some are programmable remotely, too.

 

As a precaution, all my thermostats have always been programmed locally. Remote control overrides those settings and can be done on-the-go, as required.

[Spenceteon]

Not so much a reply to this thread, but maybe a new question:  How do I establish a humidity set point (maybe a variable) and a initial HVAC fan state variable and call the HVAC fan and Dehumidifier (on an IO Linc) whenever the humidity exceeds the set point?  Then have the fan resume it's initial state?  I also have a button in the master bath to call the fan and drop the HVAC by 1 degree when pressed, then go back to auto when pressed again - how do I make it smarter and set variables for the initial fan state and temperature so that it will go back to the original settings with some intelligence?

I was thinking of having a dimmer switch near the thermostat to raise or lower the humidity set point if needed, but I understand that the variable is only internal (so far as I know).

[stusviews]

Not so much a reply to this thread, but maybe a new question:  How do I establish a humidity set point (maybe a variable) and a initial HVAC fan state variable and call the HVAC fan and Dehumidifier (on an IO Linc) whenever the humidity exceeds the set point?  Then have the fan resume it's initial state?  I also have a button in the master bath to call the fan and drop the HVAC by 1 degree when pressed, then go back to auto when pressed again - how do I make it smarter and set variables for the initial fan state and temperature so that it will go back to the original settings with some intelligence?

I was thinking of having a dimmer switch near the thermostat to raise or lower the humidity set point if needed, but I understand that the variable is only internal (so far as I know).

 

Which thermostat?

 

Also, I'm not sure what you mean by a, "variable is only internal." There are state variables and integer variables. (Do you know the difference?) Virtually anything (i.e., device, program) can be used to set and/or change the value of the variable.

[Spenceteon]

Hi stusviews, thanks for asking!

I have the #2441TH.  Not sure if there's a version, but I bought it in either late 2013 or early 2014.

I misspoke when I said that the variable is only internal - what I meant that neither the humidity nor the current temp. value appears as a status option for the "Thermostat - Heat Control," "- Cool Control" or "- Main" in a Program Condition Statement or in a scene.  For instance, how would I turn on all of my ceiling fans when the room temperature increased to 75 according to the thermostat, and I wanted the occupants to feel cooler without turning on the air conditioner?  Where do I read the current temperature or humidity according to the thermostat?

In my two use cases, I'd like to turn on my whole home dehumidifier and set the HVAC "Fan Setting" to "ON" whenever the humidity at the thermostat read above 55%, and turn it back off then the humidity returned to 50% or below and return the HVAC fan to either auto or whatever it's previous state was before the dehumidify call.  The other use case would turn on a humidifier when the humidity dropped below 38% and turn it back off when the humidity increased to 40% or more.  (the humidifier is in a different building than the dehumidifier, so don't worry about them interacting)

[Spenceteon]

Two other things:  1. The thermostat in question is a device #29.

2. My thought for external selection of the humidity set point (besides going to my eK-ISY app or Insteon app) would be through a 2477D Switchlinc Dimmer.  I would run a calculation on the internal integer variable when the set point was selected on the dimmer so that the led indicator would make the full range of motion, but only move the set point in a smaller "Comfort Zone" range from 60% to 40% or off.  I can probably get that part, but reading the current humidity from the thermostat so I can make the comparison is really my problem.

If this all works, then I'll have the light pipes for the 2477D LED indicator set up in a red-white-blue bar graph.

[stusviews]

If

        Status 'your thermostat' [is, is not, <, >, <=, >=] [1º to 122º (Temperature)] [0% t0 100% (Humidity)], many more options available

 

Then

[Spenceteon]

If

        Status 'your thermostat' [is, is not, <, >, <=, >=] [1º to 122º (Temperature)] [0% t0 100% (Humidity)], many more options available

 

Then

 

Great!  I see that now, thanks!

Does this mean that I'll need a program for each possible "Case" in the range of my set-point variable?  I'll have 40, 41, 42...60% as possible set-points.  There's no "CASE" function, so I'd check whether the switch is off and just turn the ioLink relay off, then check whether variable was 40 and the status was > 40% (Humidity) and turn on, else off, and so on until I'd covered all the possibilities?  I'm starting to think that MY comfort level is more like 45% to 55% LOL.

[stusviews]

You don't need a program for each case in your range. You can set a range:

 

Within the range
If
        Status  'Your Thermostat' >= 45% (Humidity)
    And Status  'Your Thermostat' <= 55% (Humidity)
 
Then
   - No Actions - (To add one, press 'Action')
 
Else
   - No Actions - (To add one, press 'Action')
 

Outside the range
If
        Status  'Your Thermostat' <= 45% (Humidity)
    Or Status  'Your Thermostat' >= 55% (Humidity)
 
Then
   - No Actions - (To add one, press 'Action')
 
Else
   - No Actions - (To add one, press 'Action')

 

There are more possibilities driven by your specific needs.
 
 

[Spenceteon]

That totally works for my second use case.

For the first use case, I was actually joking about the 45-55% thing - there will really be a dimmer to set the integer variable that I'll be comparing to the thermostat RH% to determine whether to turn the dehumidifier on.  I'm well on my way in the programming to set the desired RH% variable vs the dimmer status.  The reading will be reversed (off at status=off, 60% on the low end of the scale and 40% at the high end) and in 5% (out of 100%) increments that relate to the 1% steps between 40% and 60% RH.  Then I need to decide if the Humidity status is greater than the set point variable.

[stusviews]

There's an ideal humidity range (you can search for that, ambient temperature as well as health issues are involved). A realistic goal is to adjust the humidity to maintain within a range, not to be at any particular point. Doing otherwise will probably drive your humidifier and dehumidifier bats, with no health or comfort benefits. I doubt that a 1% change in humidity will alter your comfort level, but I really don't know your sensitivity

[ScottAvery]

Per a recommendation on this or a similar site, I use a digital humidity controller that has an outdoor thermometer and calculates the appropriate humidity level completely independent of my automation.  The advice was you shouldn't be guessing at humidity level as there are factors beyond indoor temperature that matter.  The structure of your home is at risk for getting it wrong.  Significant damage to wood for going too low, and damage to everything else for going too high...

[KeviNH]

I'm a "set it an forget it" kind of person, so in the winter I turn on the humidifier and just try to keep the interior above 40% RH (can be tough when using the wood stove). And in the summer I try to keep the humidity below 55%.
 

If you are using the ISY for automation and are comfortable with it, you may be better served doing all your scheduling inside the ISY and leave the thermostat unprogrammed.  ISY can do everything the thermostat can, and more.

 
I went with the opposite approach  -- I let the (Honeywell Z-Wave) programmable thermostat do it's thing, and just have the ISY controlling it when I need to override the programmed schedule.   For example put the Honeywell into "Energy Save" (setback) mode when ISY knows there is nobody home, and set it back to following the schedule when either Geofencing or an explicit command tells ISY that I'm headed back home.

 

Per a recommendation on this or a similar site, I use a digital humidity controller that has an outdoor thermometer and calculates the appropriate humidity level completely independent of my automation.  The advice was you shouldn't be guessing at humidity level as there are factors beyond indoor temperature that matter.  The structure of your home is at risk for getting it wrong.  Significant damage to wood for going too low, and damage to everything else for going too high...

Unless you have an expensive art or stamp collection, it's not quite that dire -- for damage to wood furniture you'd have to let humidity reach the extremes of high or low levels to have problems.   Floating around 50% +/- 10% is fine.

 

If you have pets and live in an area with fleas and ticks, indoor humidity below 50% makes more difficult for insects to thrive in the living area.

[apostolakisl]

There is a lot more to perfect humidity than just indoor and outdoor temp.

 

It has a ton to do with your insulation.  Extremely good insulation and you can go with a much higher indoor humidity.

 

The problem is condensation and mold.  If you have poor insulatoin and poorly designed vapor barriers, warm humid air from inside can find cold surfaces in your walls and condense.  The same in reverse can happen when it is warm and humid outside and you are air conditioning your house.  Northern homes typically have to keep a vapor barrier on the interior sideo of the insulation and in Southern homes you look to vapor barrier on the other side of the insulation.  Also a big deal when putting in a refrigerated room/wine cellar.  If you live somewhere that spends a lot of time at each extreme. .. well I don't know?  Closed cell foam?  That is a vapor barrier in its entire thickness.  (note: never vapor barrier both sides of your insulation)

 

The best humidity for humans and the stuff in your house is typically right around 50% and has nothing to do with outside temp.  The Monet hanging on your wall doesn't give a rat's a** what the outside temp is . . . right?

[ScottAvery]

For the 10% of homes with proper insulation your approach may work, but because few have it, I believe you have given the exact reasons you need to have humidity adjusted relative to both indoor and outdoor conditions.  In my previous installation fogging of windows was a source of annoyance that the controller dealt with.

[paulbates]

Latitude and window type need to be factored in, in higher latitudes, windows can get condensation and frost up if the humidity is too high. There are equations that figure that out. Nodelink does it for Venstar thermostats.

 

This article has a good explanation and a practical table for outdoor temp vs indoor humidity

http://chicagowindowexpert.com/2010/12/09/top-10-causes-of-window-condensation/

[apostolakisl]

I wouldn't worry about frosty windows.  The windows could eventually get rot on the muttons/frames, but that would be a slow and obvious thing.  It is the mold in your walls that you'll never see and could explode out of control before you know it.   That is the problem.

 

Good windows might go along with well implemented wall insulation.  Or maybe not.  Especially if you replaced the originals with better ones.

[Spenceteon]

Lots of good thought going into this! 

My dehumidifier installation in on the Texas Gulf Coast, and I think we're at 30º latitude...  I seldom see humidities below 40% inside or outside unless something really strange happens with the weather.  The humidifier is actually for an indoor walk-in cigar humidor at a business in Houston.

The occasional foggy mornings that are right about room temperature outside bring in lots of humidity, and there are no A/C calls to bring it down.  This is especially true at those times when people also are taking showers.  In general, I don't care all that much about the precise humidity, and since I'm going by the LED's on a dimmer switch, I don't really have that precise of an insight on the actual humidity unless I look at the thermostat, but since I was writing the programming, I just copied and changed as I went and incorporated the entire comfort range in 1% increments since it's available from the dimmer.  My dehumidifier isn't tremendously oversized, and it will take a long time to bring the humidity back into range when it is called, so I'm not worried about driving it batty.  I'm sure that before it gets the humidity down, the A/C will be called to keep the temperature in check, and the humidity will drop anyway.

I still think we deserve to tune it so that we don't get chapped lips/hands, but don't grow mold in the showers either, nor should we feel sticky or overly warm at a certain temperature just because of the heat index.  We will also be able to 'kick it down' if we do have showers going or are boiling something in the kitchen or mopping or whatever adds humidity to the house - just so we can stay 'ahead' of the gain in humidity.

It's purely for comfort.  I've never seen excessive humidity or dryness in this house since we've lived here except during Harvey, but we've previously manipulated it with the cooling system as much as possible before installing the dehumidifier last week.  In fact, I have a scene that turns on the A/C, drops the set temperature, and turns the fan to "always on" when you press one of the 8-way buttons in the master bath.  If I'm going to take a shower (and my wife is putting on makeup), you just press the button and the house cools and removes excess humidity.  I still have to figure out how to reverse that progress with the programming.

[apostolakisl]

Lots of good thought going into this! 

My dehumidifier installation in on the Texas Gulf Coast, and I think we're at 30º latitude...  I seldom see humidities below 40% inside or outside unless something really strange happens with the weather.  The humidifier is actually for an indoor walk-in cigar humidor at a business in Houston.

The occasional foggy mornings that are right about room temperature outside bring in lots of humidity, and there are no A/C calls to bring it down.  This is especially true at those times when people also are taking showers.  In general, I don't care all that much about the precise humidity, and since I'm going by the LED's on a dimmer switch, I don't really have that precise of an insight on the actual humidity unless I look at the thermostat, but since I was writing the programming, I just copied and changed as I went and incorporated the entire comfort range in 1% increments since it's available from the dimmer.  My dehumidifier isn't tremendously oversized, and it will take a long time to bring the humidity back into range when it is called, so I'm not worried about driving it batty.  I'm sure that before it gets the humidity down, the A/C will be called to keep the temperature in check, and the humidity will drop anyway.

I still think we deserve to tune it so that we don't get chapped lips/hands, but don't grow mold in the showers either, nor should we feel sticky or overly warm at a certain temperature just because of the heat index.  We will also be able to 'kick it down' if we do have showers going or are boiling something in the kitchen or mopping or whatever adds humidity to the house - just so we can stay 'ahead' of the gain in humidity.

It's purely for comfort.  I've never seen excessive humidity or dryness in this house since we've lived here except during Harvey, but we've previously manipulated it with the cooling system as much as possible before installing the dehumidifier last week.  In fact, I have a scene that turns on the A/C, drops the set temperature, and turns the fan to "always on" when you press one of the 8-way buttons in the master bath.  If I'm going to take a shower (and my wife is putting on makeup), you just press the button and the house cools and removes excess humidity.  I still have to figure out how to reverse that progress with the programming.

Your situation is not a building issue.  From the standpoint of damaging a structure, it would be virtually impossible to over dehumidify.  And on those problem days you refer to, the temp inside and outside is basically the same . .  so condensation won't happen.  You may have issues with your cigars, I don't know much about what humidity they like.

 

Problems in the south often times revolve around over-sized AC units that cool, but dom't dehumidify.  Combine that with a poorly implemented insulation/vapor barrier and you have condensation under the outside sheathing of your home.  This is much more of a problem in the south because mold is just all around more prevalent.  Plus, once you do get the condensation, it tends to create wet stuff that is also at a good temp to grow mold. 

[KeviNH]

Your situation is not a building issue.  From the standpoint of damaging a structure, it would be virtually impossible to over dehumidify.  And on those problem days you refer to, the temp inside and outside is basically the same . .  so condensation won't happen.  You may have issues with your cigars, I don't know much about what humidity they like.

I agree -- low humidity results in mostly cosmetic issues, gaps in floors and drafty doors and windows.   

 

Friends moved from the Midwest to the West;  Three years after moving to the high desert (outdoor humidity generally in the range of 15-25% RH) their old wood furniture started to fail, mostly coming apart at glued joints.   It is difficult to keep cigars in good condition, gotta use a tupperdor.

 

So even at the crazy low < 25% levels, actual damage took years.

[apostolakisl]

I agree -- low humidity results in mostly cosmetic issues, gaps in floors and drafty doors and windows.   

 

Friends moved from the Midwest to the West;  Three years after moving to the high desert (outdoor humidity generally in the range of 15-25% RH) their old wood furniture started to fail, mostly coming apart at glued joints.   It is difficult to keep cigars in good condition, gotta use a tupperdor.

Mother nature can do that for sure (in the desert).   But, man, it would be one hell of a dehumidifier that could pull humidity down that far (in an environment where it would natuarlly be higher).

 

As an example.  Sadly, a few years ago, I had a major pipe break and it flooded my office.  They sucked out the water and put maybe 8 gigantic dehumidifiers in a space of about 4000sf.  The humidity got below 40, but barely.  My electric bill that month was quite special too.