As the smart home rises in popularity among consumers, so do the sales of smart thermostats, which are often considered the gateway into the smart home. In fact, smart thermostats are expected to grow at a compound annual growth rate of 20 percent between 2018 and 2023, reaching a value of $3.4 billion by 2023, per a study from Markets and Research.

However, research from Parks Associates indicates that more than 100 million homes in the U.S. did not have a smart device in 2016. That same study predicts more than 40 million homes will have a smart thermostat by 2020.

The expected surge in smart thermostat sales will have equipment manufacturers, many of whom have their own proprietary controls, competing with the well-known universal thermostat brands, such as Nest, Honeywell, and ecobee.

The question remains, what is better for consumers: HVAC equipment that supports the use of any universal thermostat, or equipment that works only with a manufacturer’s control? The answer, it seems, is that it depends on the consumer and what they want.



Carrier Corp. prides itself on the fact that its systems are compatible with all 24-V thermostats available on the market today, according to Siva Iyer, director of product management for Carrier. However, the manufacturer does have its own line of proprietary controls.

“We have the higher-tier, higher-efficiency, and higher-comfort equipment with our Infinity and Evolution series,” Iyer said. “While those are designed to work with 24-V controls — the universal standard — our own proprietary line of controls for those systems really enhance the functioning of that equipment to a large degree.”

Iyer noted that there are a lot of incremental benefits to using Carrier’s Infinity or Evolution series controls, including low noise, improved comfort levels, improved humidity management, and more. However, any system that works only with the manufacturer’s thermostat, under any circumstances, really limits customer choice.

“That’s not something we would ever like to do,” Iyer said. “Customers have the right to put whatever they want on their wall. Now, we of course say, ‘If you want to make a better choice, if you want improved comfort, higher efficiency, and fully modulating zoning in one control, we may have a better choice for you in our proprietary control.’ But if the consumer likes their current thermostat, if they are already used to it, like the shape, the feel, or the color, then absolutely we’ll support that. They just won’t get the added benefits I mentioned earlier. It’s about giving the customer options.”

Iyer added that Carrier not only offers consumers greater control over comfort and efficiency, but it also offers dealers advanced tools. Additionally, it is adding smart home capabilities and interfaces. Carrier thermostats are compatible with Amazon Alexa (Echo) and Google Home, and the company is working on adding integrations with other platforms that homeowners and dealers are coming to expect.

“We’re excited about all these new developments taking place,” Iyer said. “It’s going to help us move faster and make life more comfortable and more energy efficient for our customers.”

All of Rheem Mfg. Co.’s HVAC systems work with any thermostat on the market today — including Rheem’s EcoNet®-enabled HVAC equipment, according to Carson Burrus, product manager - HVAC IoT Controls at Rheem.

“Rheem’s EcoNet-enabled systems are considered by industry standards to be communicating systems,” Burrus said. “However, to maximize equipment performance, comfort, and savings, Rheem recommends pairing EcoNet-enabled HVAC systems with the company’s communicating EcoNet Smart Thermostat. Should a communicating HVAC system be wired with a non-communicating thermostat, homeowners will experience a significant decrease in efficiency and comfort, and contractors will lack valuable diagnostic information and equipment status, including critical alerts and alarms that drive first time resolution when service is required.”

OEMs have taken the time to understand contractor and consumer needs and have developed thermostats that rival the design and quality of popular smart thermostats that are currently on the market, Burrus noted. Rheem thermostats are equipped with features that homeowners have come to expect, such as full touchscreen, voice control, local weather, one-touch away, motion activation, and more.

“The advantage of having a system that can work with any smart thermostat on the market is the consumer attraction, ultimately leading to more brand credibility and probable increased product sales,” Burrus said. “Rheem’s current brand focus is continuing to add to our list of industry-first systems through innovation and close dialogue with our customers.”



Goodman Mfg. Co. L.P. took the concerns of its dealers and homeowners into account when it developed its latest ComfortBridge™ technology, according to Jim Fisher, director of controls at Goodman.

“HVAC dealers and homeowners raised concerns regarding a better way to allow a new HVAC system to connect easier to an existing thermostat or allow a universal option to thermostat connections,” said Fisher. “HVAC dealers and technicians needed a better method to connect, configure, and diagnose HVAC systems.”

Goodman took the communicating control board out of the thermostat and placed it securely inside the gas furnace and air handler to create its ComfortBridge technology. Bluetooth connectivity is also included in the indoor unit. It allows the use of any single-stage thermostat to work with a ComfortBridge technology-compatible HVAC system.

“An advantage to HVAC dealers is that when installing a ComfortBridge technology system, the consumer is typically not forced to replace the current thermostat in the home regardless of whether it’s a single-stage or smart thermostat,” he said. “HVAC dealers can potentially reduce the variety of thermostats necessary to support their customer base and, in many cases, not have to disturb what is currently installed in the customer’s house.”

Another added benefit is expandability. It is very simple with ComfortBridge technology.

“We have approximately a half dozen major initiatives that we’re going to tie into this product that we’ll work on throughout the next couple of years,” Fisher said. “As we get those up to speed, we have over-the-air updates in the equipment, so the technician in the field … can make updates to that equipment from a connected phone.

“This is not a really new concept,” he added. “It’s something we do with lots of systems connected to our cellphones in our homes, but not very often with HVAC equipment.”

Additionally, through Goodman’s Cool Cloud app, a technician can connect to the equipment via Bluetooth technology built into the indoor product. This allows the tech to access setup and diagnostics via a smartphone or tablet.



Dennis Thoren, vice president, Controls for Daikin, likens proprietary Daikin controls to a stereo system in a premium car brand.

“Basic universal control systems (thermostats) all work off of 24 V,” Thoren said. “They’re simple on/off controls, and this is generally what you see with lower-tiered systems having efficiencies that range from the industry minimum allowed up to mid-efficiencies of around 16 SEER. Most HVAC companies have their own proprietary communication protocol for their higher-end equipment, which is basically digital communication with a much more precise control of each of the components in the HVAC system.”

In addition to comfort and efficiency, Daikin provides a lot of diagnostics through its controls for its complex, higher-end systems, like variable refrigerant volume (VRV). Proprietary smart thermostats offer the best of two worlds. Thoren noted that first, they are precisely tuned to work with the proprietary equipment in order to help maximize comfort, efficiency, and dealer remote diagnostics. Second, they also have the ability to provide the open Wi-Fi protocol needed to work with today’s smart home solutions.

“We send that diagnostic information through the digital communication wires to the smart thermostat,” Thoren said. “We want to make it easy for homeowners and dealers to understand how the system is operating, particularly for our Daikin Comfort Pro™ dealers, who we want to be able to see and diagnose issues, not only with the smart thermostat, but also remotely using the same interface, so it’s convenient for them.

“Basically, we’re selling a high-performance, premium system,” he continued. “It’s like buying a luxury vehicle. There are components that are designed to work with that vehicle, and you could put in a different stereo system if you really wanted to, but it would be very difficult, and most people wouldn’t choose to do that, because they’ve produced something that provides all the features that a luxury vehicle owner would want. It’s the same philosophy for smart thermostats. Thermostat controls is a very competitive market and there are a lot of very good, unique controls offerings. So the challenge for OEMs, such as ourselves, is to make sure we’re not only providing the best experience for our dealers but also providing a competitive and unique consumer experience.”

There are benefits for HVAC equipment compatibility with universal smart thermostats at lower efficiency levels, Thoren said.

“Choices are always good for homeowners,” he added. “We are providing choices not only for the smart thermostat, but for the system with different system configurations by targeting what they’re really buying, which is efficiency. It’s a different brand position in the market.”

Sweta Hari, director, product management, controls, Lennox Industries, said Lennox sells its S30 thermostat as part of its highest-efficiency communicating products. This top-tier bundled system is called the Ultimate Comfort System. Additionally, Lennox’s Precise Comfort technology allows it to modulate the equipment. The Ultimate Comfort System uses the iComfort S30 to control the a/c and furnace within a 0.5°F precision on comfort, so homeowners don’t experience huge swings in temperature.

“This allows them to feel comfortable without having to think about it,” Hari noted.

Most Lennox customers who buy this system are tech savvy and know the advantages of buying a complete, compatible high-efficiency system versus just buying a thermostat, Hari added.

“Most of the time, people looking for compatibility aren’t as concerned about system energy savings and aren’t set on a specific system,” she said. “It could be a person renting or not staying in a home for many years. Most Lennox customers are highly vested in both quality and comfort, so having a Lennox smart thermostat that is compatible with the system and that brings out the most efficiency and utilizes all of the important comfort features they are expecting is key.”

Hari explained that universal thermostats often offer basic features, with minimal diagnostic and prognostic capabilities.

“One of the major differentiators for Lennox smart thermostats is that we give the homeowner the option to have their dealer monitor the system, giving homeowners peace of mind,” she said. “Anytime there is a system alert or issues, the Lennox dealer that services that residence gets the alerts remotely, and in some cases, the dealers can remotely run diagnostics and access the heating and cooling system, saving themselves a home visit.”

There is a lot of discussion about what is best in terms of the pros and cons of a universal thermostat. Lennox believes that for homeowners looking for the best quality and service, a thermostat that’s compatible with the system is best in the long run.

“It allows them to have more advanced options, especially looking to future diagnostics and prognostic capabilities,” Hari said. “Most importantly, homeowners have a sense of ownership when they have a brand of thermostat associated with their equipment.”

Publication date: 11/12/2018

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