Did you hear the one about Nest thermostats dying overnight because of a bug that caused the batteries to drain? It left a lot of customers in the cold. Like freezing cold.
The problem was related to the way Nest thermostats are powered — by “power-stealing” from the HVAC control wires, rather than through a dedicated common wire, or C-wire. Power-stealing can work, and it's often the fastest track to DIY, but it is never the best option for charging a thermostat battery, especially when the thermostat employs a power-hungry Wi-Fi radio.
In the case of the most recent Nest glitch (and others), the thermostat batteries ran out of juice.
Nest co-founder and VP engineering Matt Rogers blamed the snafu on a software update from two weeks prior.
Nest worked overtime to fix the problem, but many customers had to follow a nine-step process — including removing the thermostat from its base — to get their comfy back.
People, especially those in the home technology integration trade, love to hate on Nest, despite Nest's extensive outreach to and support for custom installers. While most integrators do embrace it – because many consumers demand it – the fact is that the thermostat is less amenable to smart-home integration than products specifically built for the cause.
Companies like RCS Technology, Leviton Security (the old HAI group), Aprilaire, Honeywell and Radio Thermostat of America specialize in HVAC control in particular, and home-systems integration to boot. With their products – often sold under major security and home automation brands – integrators can tap into a wealth of features (like fan control) that Nest currently does not expose.
CE Pro reached out to some manufacturers when the Nest glitch occurred, wondering if their products faced the same exposure as in the Nest case.
Paul Williams, VP of solutions for Control4, says thermostats tailor-made for rich HVAC integration address some of the challenges of standalone cloud-based thermostats, especially Wi-Fi models.
The Control4 Thermostat, for example, has the option to be powered via standard 24V home HVAC wiring and/or 4 AA batteries “for the most installation flexibility and reliability,” he says.
But there’s another issue at play with systems from Control4 and other purveyors of custom-oriented control systems: There is (or should be) a professional integrator testing software updates before pushing them out to their clients.
“Control4 installers are responsible for completing any updates for our customers,” says Williams. “Dealers and their customers are not caught off guard by OTA [over-the-air] Wi-Fi updates.”
RCS Technology, a leading OEM for many home-control manufacturers, had this to say about thermostat selection: “C-wire, C-wire, C-wire,” in the words of RCS founder Michael Kuhlmann. “Better to take the extra effort to get high-performance thermostats, especially power-hungry Wi-Fi ones, installed correctly with a common wire,” he says.
Kuhlmann adds, “Power stealing was always a poor alternative to getting a professional installer to do it right. We have never used it for that reason.”
6 Tips for Thermostat Selection
Aprilaire, a long-time leader in integration-friendly HVAC systems, went a little deeper on the issue of HVAC integration, outlining six features that dealers (and consumers) should consider when purchasing products for temperature control and indoor air quality (IAQ).
The company, by the way, has recently introduced its first Wi-Fi thermostats. These recommendations come from Jon Fischer, HVAC automation sales manager.
1. Designed/manufactured by an HVAC company
When choosing a thermostat, select one from a company that is known in the HVAC industry and has a long history of innovation and success. HVAC companies understand all the features needed to make sure HVAC equipment is protected from extreme weather and realize that the primary function of a thermostat should be reliable control of the heating, cooling and IAQ systems.
Specifically if you are in an area where heat pumps are prevalent with a gas fired furnace as a back-up heating source make sure that your thermostat supports Dual Fuel with Balance points. This way the thermostat will lock out the compressor when the outdoor temperature drops below a selected set point which will 1) minimize the amount of compressor run time when it is not efficient 2) protecting your compressor from any type of damage that could be done by running the compressor when it is too cold outside and 3) saving money on unnecessarily running the compressor.
2. Has a common wire
A thermostat with a C-wire (or common wire) does not rely on batteries being charged, but is powered via 24 volts. This is especially important for Wi-Fi thermostats because they require more power to maintain network connectivity. A C-wire will help ensure a reliable connection and proper operation.
3. Stand-alone operation
First and foremost, a thermostat needs to control the HVAC system. When a firmware upgrade is pushed to update a thermostat, you should ensure no changes will be made to how the thermostat controls the heating and cooling system. Also when firmware is sent you should make sure that the settings (type of HVAC system, mode of operation, program) are not defaulted back to factory settings.
4. Works with all control companies
While control systems are a staple for most system integrators, if or when you do change manufacturers it can be easier and less expensive for the end user if you find a thermostat that works with all or most control systems.
5. Local internal network communication
Find a thermostat that communicates directly to your automation system. There are several thermostats out there that force you to communicate to their cloud. Often times this cloud has some restrictions on number of communications per hour. Also if the Internet goes down you lose control of your HVAC even though your internal network is fine.
6. Automatic humidity control
Most automation thermostats have the ability to control humidity. However, not all control methods are the same. Automatic humidity control monitors the outside temperature and adjusts indoor humidity levels to prevent condensation on windows and other harmful effects of too much moisture. Automatic humidity control provides the balance needed to improve comfort and health while protecting artwork, wood floors, and musical instruments.
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