HVAC System: Communicating vs Non-communicating – Is It Worth the Money?

Perhaps you’ve heard the benefits of communicating vs non-communicating HVAC systems while exploring what system is right for your home. For the extra cost, typically 20 to 50 percent depending on the systems you’re comparing, communicating HVAC equipment delivers:

  • Higher efficiency
  • Optimized indoor climate control
  • The brand’s best warranty

That’s a lot to like! So, in this communicating HVAC guide, we answer common questions comparing the two types of systems, pros and cons of communicating HVAC and whether the extra expense is worth the improved performance you might receive.

HVAC System: Communicating vs Non-communicating Technology

To understand communicating equipment, it might help to first explain in moderately technical language how each type of HVAC system works. If you’re not interested in the technical side but simply want to know the pros and cons and whether communicating HVAC is right for you, feel free to skip this section.

Non-communicating HVAC:

  • Used with single-stage and two-stage heating and cooling with gas furnaces, central air conditioners, heat pumps and air handlers
  • The thermostat is the switch – If there’s a call for heat, for example, the thermostat closes contacts to complete a circuit and deliver voltage to the relay, which closes other contacts to extend the voltage to the furnace or heat pump
  • When the thermostat set point is reached, the thermostat opens the contacts, and the circuit is opened (broken), preventing voltage from reaching the furnace or heat pump (effectively turning it off)
  • Every function is controlled by a separate wire that is energized when the thermostat calls for that function

The benefit of a non-communicating HVAC system is that it is the standard type of system that every technician knows how to install and service. When there are issues with the system, they are easy to detect and repair.

One minor difficulty is that that non-communicating thermostats contain up to 12 wires for the many functions possible—furnace, AC, second-stage furnace, second-stage AC, heat pump, heat pump reversing valve, blower motor, fan only mode, auxiliary heaters in heat pumps plus the c-wire, or common wire. Therefore, it takes more time to wire systems with multiple functions, and there is more opportunity for inexperienced HVAC technicians to make an error.

Now, let’s compare communicating vs non-communicating by listing the features of communicating HVAC systems.

Communicating HVAC:

  • Used with some two-stage and all variable-capacity HVAC systems
  • Require just four wires – two power wires for heating and cooling and two for communication between components
  • When communicating equipment is installed, the thermostat searches for the components in similar fashion to how your smartphone searches for a Bluetooth speaker you want it to pair with
  • Once the thermostat and components are paired, the components communicate to the thermostat what their capabilities are in terms of heating and cooling capacity and, for blower motors, how much air they can move through the system, which allows the thermostat to set up optimal performance
  • Each component has an electronic address, so the thermostat knows where the data is coming from and can send data back to that component to control its operation
  • A computerized serial network allows each component to send ongoing performance data that refines performance
  • Indoor and outdoor sensors allow the thermostat control to determine and communicate exactly how much heating or cooling, dehumidification or humidification and air flow are required to keep the home optimally comfortable

Where is Trane Communicating Circuit Located

Where is Trane Communicating Circuit Located

Communicating HVAC Pros and Cons

Carrier was the first to develop communicating technology and the only brand to offer it for a few years. Now, all major HVAC brands offer communicating systems. There are distinct pros and cons.

Communicating HVAC system pros:

  • The highest efficiency ratings and lowest operating costs of any type system
  • Modulating heating, cooling and blower speed to precisely balance temperatures
  • Lower noise levels due to system components running at less than maximum capacity
  • The best dehumidification when air conditioning
  • Optimized comfort control in standard and zoned systems
  • Data exchanged between components allows the system to diagnose issues and alert technicians for tuning the system for best performance, providing maintenance and making repairs
  • Notifications alert homeowners to the need for minor maintenance such as changing an air filter or cleaning a condenser

Communicating HVAC system cons:

  • Communicating equipment is significantly more expensive than non-communicating equipment
  • Some communicating systems from all brands tend to stop communicating, and getting them to communicate again can be difficult
  • Repairs to communicating equipment are much costlier
  • Many technicians do not have experience installing and setting up communicating HVAC technology

Communicating HVAC FAQs

The answers to these questions will assist you in making your decision in the communicating vs non-communicating HVAC debate:

Can I mix non-communicating and communicating components?

It depends on the brand and piece of equipment. If it is possible, the communicating components and the thermostat will have to be rewired to be non-communicating. You will lose any communicating capabilities. Check with your HVAC pro to determine if your communicating system can be modified and if you’ll need a different thermostat.

What is a matched HVAC system?

This term refers to building an HVAC system with all communicating or non-communicating components, so they are designed to work together.

Can I mix communicating components from different brands?

Only if the brands are sister brands made by the same manufacturer. Such pairs include Carrier and Bryant, Amana and Goodman, Maytag and Westinghouse, Heil and Comfortmaker, Trane and American Standard.

Will a communicating thermostat from one brand work with communicating equipment made by another brand?

Only if the brands are sister brands (see last answer). For now, each manufacturer is making proprietary communicating technology.

Do I have to use a communicating thermostat with communicating equipment?

To get full communicating performance, you must use a communicating thermostat.

Is a smart thermostat the same as a communicating thermostat?

The term “smart thermostat” usually refers to a Wi-Fi thermostat that can be controlled with a smartphone. Some communicating thermostats are also smart thermostats, but the terms do not refer to the same capability.

Do Nest, Ecobee and Lyric thermostats work with communicating systems?

Yes, but only if the system is wired to function as a non-communicating system. There are no third-party thermostats that work with communicating HVAC systems.

What is ClimateTalk?

ClimateTalk is a partnership between manufacturers such as Emerson and Johnson Controls (York, Luxaire, Coleman brands). One of its goals is to produce an open communicating protocol that will be standardized across all brands. That will mean, should it succeed, that communicating equipment not made by the same manufacturer will work together.

What do the major brands call their communicating systems?

  • Carrier: Infinity (or Greenspeed)
  • Bryant: Evolution
  • Amana, Goodman and Daikin: ComfortNet
  • Trane and American Standard: ComfortLink II
  • Rheem and Ruud: Comfort Control System
  • Lennox: iComfort
  • Maytag, Tappan, Westinghouse and others: iQ Drive
  • Heil, Comfortmaker, Keep Rite and others: Observer
  • Armstrong Air: Comfort Sync
  • York: Affinity
  • Luxaire: Acclimate
  • Coleman: Echelon

Is a Communicating HVAC System Worth the Money?

HVAC contractors are divided on whether communicating systems are worth the money. Tim Austin, of Austin Air in TX, recommends communicating systems. His reason is that, “Communication between parts makes for one smart air conditioner and a really comfortable customer. It also delivers better performance, better comfort, better reliability, and better warranty coverage.”

A tech from Israel AC and Heating in Louisiana shares the other side in a YouTube video, saying, “this is exactly why I do not like communicating equipment. The component control board [sometimes] fails to send a communication to the thermostat, and solving the issue can be very difficult.” His solution is to eliminate the communicating function and replace the communicating thermostat with a two-stage model. In cases like that, the homeowner has wasted money on communicating technology and ends up with a two-stage system after the expense of a new thermostat and the service call.

Our answer is that a communicating HVAC is worth considering if:

  • You plan to live in your home at least 7-12 years, the time it will take (depending on your climate) to recoup the higher cost of communicating equipment through lower energy bills
  • Being environmentally conscientious is a top priority for you, so you’re willing to pay more to get the higher efficiency offered by communicating HVAC systems
  • You’re planning to replace your entire HVAC system, since the system must be matched including the thermostat
  • Optimal indoor comfort including balanced temperatures, superior humidity control and quiet operation is important to you
  • You’re willing to take the risk of higher potential repair costs
  • You find an HVAC installer with a proven track record of proper installation of communicating systems

There’s no doubt that many of the problems with communicating HVAC systems are due to faulty installation. Since the technology is newer and systems are wired and tuned differently than non-communicating HVAC, some installers don’t have the experience to do it correctly. If you want to get free quotes from some of the top communicating HVAC system installers in your area, use our Free Local Quote tab. There’s no obligation. The installers are pre-screened to be licensed, insured and experienced, and they know they’re competing for your HVAC job.

Do you have a communicating system? Let us know what you think by using our HVAC Review tab. If you’re still considering the decision, our readers would benefit from hearing what you decide to buy and how much it cost. Our Share Your HVAC Price tab is the place to share that information for the benefit of other readers. Thanks for your time! If this has been helpful for your research, please pass it along to friends and followers using our social media tabs.

Written by

Rene has worked 10 years in the HVAC field and now is the Senior Comfort Specialist for PICKHVAC. He holds an HVAC associate degree and EPA & R-410A Certifications.

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26 thoughts on “HVAC System: Communicating vs Non-communicating – Is It Worth the Money?”

  1. I have a York system with an Affinity thermostat. I get frequent communication fault meaasges. The AC techs don’t have any good tools to troubleshoot communication problems and York isn’t any help.

    I like Nest thermostats but the York unit only works with their proprietary Afinity thermostat.

    I am an electronics engineer who works with instrumentation and controls. My advice is to stay away from systems with communicating thermostats until the bugs are worked out of the designs.

    • I also have the York Affinity system, and it worked fine for a few months, and then I got Communications fault codes. I am an Industrial Electrician so I looked into how the control wiring was done by the contractor. It was connected as most systems would be, but according to Yorks install sheet, you can not land but one set of wires on a terminal strip. So I made a dongle that would enable this to happen. I called my installer and told him of the issue, and that I wanted to replace the standard cable he used with a shielded cable and instructed him as to how to ground one end of the cable and only one end to prevent ground loops and allow the shielded cable to work as intended. This new cable also is gel filled meaning if there is a breakdown or nick in the cable jacket it self heals much like some direct burial telephone cable does.

      After the new cable install, with the factory approved wiring method installed I had about 8 months with no faults, then all the sudden they came back randomly, sometimes back to back, if I was not home to “RESET” the thermostat my house would be hot or cold depending on the season because it shut the unit down until the user clears the fault.

      At this point I called York directly, which by the way takes forever to get the right TECH on the phone. They had me reset the Thermostat, I also cleared all fault codes by downloading them onto a thumb drive, disconnected the thermostat, and once it powered back on I did a factory reset on the T-stat. So far I have not had any more faults, but I am wishing I had just got a “Dumb” unit now. If this continues I can tell you it is not worth the money especially when the fault codes are communications issues that do not mean something is wrong with the indoor or outdoor unit other than they did not speak to one another for a cycle and the result is you have to source of heat or cooling until you physically reset it.

      • @Marlin: If your problem continues, you might consider installing a relay rigged to a timer to reset the A/C every day. This would likely violate the thermostat warranty, though, unless they’ve provided terminals which it sounds like they haven’t. And you need to make sure your timer is battery-backed and reliable, too.

        Thanks for the report!

        • This is not what the homeowner wants to hear as an answer! I’m not saying your suggestion won’t work; I’m just saying there has to be a better way. If I spent $10-20k on a system, I would be less than pleased to hear an answer like this. (I worked on an HVAC job once where our contract was over $500,000.00. Could you imaging giving this sort of answer to that customer!?

    • I would wrap communication wire around two ferrite for a high and low frequency’s… at the thermostat

      Or disconnect the wires and look at the with a spectrum analyzer…

      If you are suppose to be a electrical engineer….you should understand what happens in a antenna..

      I’m not a electrical engineer, I just fix their f-ups

    • This is a follow up on my previous review. The firmware in the thermostat was updated and it appeared to solve the intermittent fault messages, but the problem returned after several weeks.

      The thermostat was replaced and the problem has not returned after 6 months.

      Given all the headaches and extra expense I think communicating systems are not a good investment as opposed to a conventional 2-stage system.

  2. I too have an Amana Inverter system with a communicating thermostat. Installed in march have had already 3 service calls for communicating errors. They changed out thermostat and changed wires around. Which I question. Also energy bill seems higher.

  3. Installed 4 ton Goodman heat pump replace the old Maytag. Live in Tampa so units get a workout with ac with some heating in winter. Originally used a lyric smart thermostat which worked good with bells and whistles but was very on/off and struggled with humidity. Changed to comfortnet thermostat and system operates night and day different. More even operation, humidity in check, runs less in stage 2 and quieter.

    • Hi Frank, I’m looking for a similar system and I live in Tampa too. Could you tell me who you used to install and maintain your hvac?

  4. Unfortunately I didn’t understand what I purchased for my central air. I had a Trane air before with 2 Condensers & the installer said it was the same like I had before. I still do not one hundred per cent fully understand how to operate my Goodman 2 stage communicator. The salesman sold me the wrong air conditioner for me.I had company for thanksgiving & they were extremely hot; I had 2 lower the air 3 two 4 degrees while I froze on my side for them to b comfortable does that make sense. That’s what the salesman said I had 2 b uncomfortable for them 2 b comfortable.My home is split where bedrooms r on both sides.Very Dissatisfied with Goodman air conditioner two-stage unit communicator

    • The two main keys to buying a communicating heating/cooling system for your home are choosing the right brand and the right contractor. As an HVAC professional, I strongly believe that the additional investment for a communicating system vs non communicating is well worth it, however, equipment and contractor selection is critical. The biggest issue with communicating systems is that a small percentage of the technicians out there actually understand how they work. Understanding them is crucial to proper installation, diagnostics, and repairs. Our company has installed over 500 communicating systems and we rarely have issues with the controls or circuit boards. Most issues are the same issues seen with any heating/cooling system, such as bad motors, leaking heat exchange coils, bad compressors, etc. As I said, choosing the right brand is important. I recommend Trane or Lennox. They provide great education and thorough troubleshooting literature for their dealers. Not to mention, the engineering of these two brands seems to be superior to almost all others. Choosing the right contractor is just as important. Some HVAC contractors believe in heavily investing in their installers and technicians. A good chunk of this investing should be in education. As technology becomes more advanced, education should become more frequent. It’s difficult for a homeowner to know the difference between a contractor like this and a contractor that is okay with deploying unprepared technicians. Homeowners have to do their research to sort through this, but here are some clues to recognize a contractor that invests in it’s workforce:
      Service vehicles are newer and kept clean.
      Technicians wear nice uniforms and neatly present themselves.
      Office staff handles your call promptly and courteously.
      The salesman has extensive knowledge of the product he is trying to sell you.
      In summary, bad contractors give communicating HVAC systems a bad name. Hire a good one and you’ll love your new system.
      By the way Dorothy, the problem you described sounds like an imbalanced duct system. The air conditioner is working fine if it can freeze one side of the house. Your contractor should have noticed duct system issues when they surveyed your new A/C installation.

      • WHAT IS THE NAME OF YOUR COMPANY THAT HAS INSTALLED 500 COMMUNICATING SYSTEMS AND IS IT IN ILLINOIS? How do I find an educated HVAC technician. What questions should I ask? Do you recommend Trane or American Standard A/C’s overall. It’s very important that it doesn’t have break downs and runs quietly. I currently have a 12 year old system that has never needed repairs just annual checks.

    • Goodman just makes the equipment…

      You have to hire a a/c guy that knows how to engineer the ducting system..

      Air flow is half of the performance of a/c system

  5. I had a Carrier Infinity HVAC heat pump and gas furnace installed and not a fan of modulating it does. You will hear the heat pump throttle up and down all day non stop. The gas furnace is nice with the modulation but what I have noticed is that when the system is set to modulate the utility tracker is way higher than setting it to run as single stage. Not very happy with the unit at all. Our next unit will be a non-communicating system preferably single but might look into a 2 stage. When we run the A/C you can never hear the system run and works really nice. Never really checked to see if it was cheaper to run the system in single stage.

  6. Of course salesmen and owners like communicating systems since they are more profitable. Technicians typically are not so fond of them and it’s not always because they don’t know how to service them. Communicating systems as we saw in an earlier comment take years to pay back through reduced power bills and that is IF there are no major problems. It’s a gamble at best. My opinion is to get a “middle of the road” system that is non-communicating and you’ll be better off for it in the long run. Some people just like all the bells and whistles so if you’re one of those people and you have the extra money I say “go for it” and we’ll just make more money on you. If you took a survey on my comment you would find that salesmen wouldn’t like it (but what does that tell you) and most technicians who really know what they’re talking about would agree with me.

  7. My opinion is it all comes down to the one purchasing the equipment. Communicating systems I find are far more superior (Based on proper install). The benefits outweigh the cons, based on ones lifestyle and long term commitment to the equipment. That being said it comes down to money. Sometimes people can’t afford to have the best equipment. Which is fine there are lots of great options out there. But home owners need to be warned about the “Smart thermostats” that claim they don’t need a c wire. If installing a nest or other thermostat, please install the c wire. It will save you in the long run. As well as they are not communicating, which seems to be lost among some

  8. I had a communicating thermostat installed when I purchased my new Armstrong furnace. When I installed a central air conditioner a few years later, I turned off the furnace to make connections. This is when my troubles began with the Comfortsync thermostat. The thermostat gave an error code because the furnace was off for more than 24 hrs. I was unable to reset the thermostat. I then went into the system analysis screen and tried to scan for problems. The thermostat program scan went on for hours before I got fed up and tried to stop it. There was no feature that would stop the run, so I unplugged it in an attempt to reboot, but this sent it in to a cycle of turning on and off. I guess the system is not meant for the typical house-owner to tamper with, you’re at the mercy of repair technicians. A service call would’ve cost me $79. I have a fairly good understanding of electronics and mechanical systems and up to a point I like to trouble shoot and repair my own equipment. This type of thermostat does not allow for this. For me it was the thermostat from hell. Also, costumer service at Comfortsync was terrible. I took the loss on this thermostat and replaced it with a non communicating one.

    • Lol. Non HVAC people doing HVAC stuff. First problem, you’re not a tech. Second problem, you went with Armstrong Air. The cheapest junk out there. Third, you didn’t replace the entire system at the same time.

  9. We had to replace our HVAC a couple of years ago and decided to go with a communicating model from Trane based on advice of a contractor neighbor. We’ve regretted it ever since, as despite additional efforts since (like having our HVAC contractor zone the house as much as possible), our temperature regulation with our old non-communicating model and Ecobee thermostat (even without the benefit of the zone controls) was superior to what we’ve experienced with the Trane proprietary thermostat. For example, our upstairs bedrooms are currently 3 degrees warmer than our cool setpoints and all other zones are above the heat set points, yet the system is heating. To fix this, it will shortly switch to cooling and freeze out our downstairs bedrooms. The ecobee used to make much better use of the fan (without excess heating/cooling) to equalize the temperature in the house.

  10. I have a Lennox communicating system with I comfort 10F81 thermostat with wifi and USB port. It is expensive $ 400.00. it has a 4 wires. all 4 wires connected behind thermostat with another 2 wires to each all 4 wires makes 8 wires. R power and Y attached to C as common. I checked power to that on R and Y FOUND 27.9 SO POWER IS THERE.Need 24 low volts. Now I can not check any thing more as thermostat went blank. no display at all. It is also out of warranty.
    easy way is to replace with same. but will it work after that or not is not unsure. and expensive. to be installed by a dealer to have warranty on new one cost 550.00 for 10 minute job
    Also it is a rental unit town home. Tenant does not know much of knowledge
    about Thermostat.

  11. I have a Bryant Evolution which I hate. I replaced the main thermostat with an Emerson Sensi and planned to do the same upstairs until I found out it was an ABCD communicating thermostat. So now I’m trying to figure out how to replace the upstairs thermostat and lose the “communicating” nonsense once and for all. No clue how to do this. Our HVAC company doesn’t get involved because I didn’t want to purchase the thermostats from them. Help!

  12. I have a Trane XC95m communicating furnace. Is the Trane Comfortlink ll XL850 thermostat compatible with the furnace? I want to have the ability to control the furnace via wifi/z-wave while I am away for the winter.

  13. So the equipment can communicate but no one can understand what the communication is. A protocol analyzer is needed that can log and decipher the communication. Sort of a translator that logs the conversation. I have looked for this for iComfort and have not found one, nor have I found a description of the iComfort message frame and content. We have this for OBD on cars, with scanner tools that allow observation and troubleshooting. Come on Lennox, not all customers are ignorant. Share how your equipment works, or we will get rid of it.

  14. I have two Heil furnaces (2-stage, communicating), installed in 2017 by previous home owner. I think its called Observer. Currently they are matched with an Observer thermostat. I want to use a Nest like smart thermostat on it. But when i swap out the thermostat, the furnace wont turn on – and I just hear one click at the beginning when I turn the furnace on and then no-go. So i put the Observer thermostat back on – and it works fine again.
    Now after reading this article I understand why the Nest wont work. How do I convert these 2 Heil furnace into a non-communicating, so I can use smart thermostat?
    (seems there is debate about using communicating system anyway)

    Any help pls?


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