HVAC System: Communicating vs Non-communicating

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 System 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?

That’s the ultimate question for many. Some HVAC installers recommend communicating systems to all their customers due to potential energy savings and climate-control benefits. Others refuse to install them because they have had too many repair issues with communicating technology. Most residential HVAC contractors are somewhere in between.

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.

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