Smart Thermostats – worth it?

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My new Ecobee 3 Lite Thermostat

Previously I had written about saving money on electricity costs using LED lights. The rationale was simply a low-cost investment in order to save several hundred dollars per year or more. This is versus trying to install a solar panel array, which has a much longer return on investment and are unreliable in outages if you can’t store the power with a battery bank.

Keeping with the theme of small, low hanging fruit investments to save money, today I will discuss smart thermostats. One of the key benefits of a smart WI-FI thermostat is that you can monitor or change the temperature setting from an app on your phone. Many people ask “why not just get a programmable thermostat”? The rationale behind that question is most savings are achieved from the programming in the thermostat rather than wifi capability. This is true if you program the thermostat properly, i.e. lower settings when you are not home or asleep. With a wifi thermostat, however, you can change the setting for 3-4 hour time periods when you are not home on the weekend or in the evening. This is aside from the ability to simply monitor your temperature when away for several days. This is a huge benefit as the thermostat serves as a potential warning trigger during a power outage. The Nest Thermostat actually has a learning function that claims to learn your patterns over time and adjusts accordingly. In the end, programmable thermostats can save up to about 15-20% of your heating and cooling costs if programmed properly, and you can add another 3-5% savings with a smart wifi thermostat.

Looking at what is available, the choice came down to an Ecobee versus a Nest and I reverted to the low-cost versions of these two, which are the Ecobee 3 lite and the Nest E. First, before explaining why I chose the Ecobee 3 Lite, let me provide my rationale for preferring the low-cost versions. I am of the mindset that most of the energy efficiency in your home is defined by insulation, windows, and ducting. For example, if you have poor insulation and old windows that aren’t sealed and caulked properly, it probably won’t make a difference if you have a smart thermostat or not. The ducting makes a difference because bends, elbows, and distance can cause a reduction in flow to some rooms. In that sense, it is better to have a 2 stage heating/cooling system especially if you have a bigger house with multiple levels. Therefore my conclusion is that a smart thermostat will help, however, I do not need the fanciest versions simply because they have a diminishing return for the additional dollars spent.

With that in mind, I chose the Ecobee 3 lite for three main reasons that were specific to my situation and preferences:

  • The lack of a “c wire” in my house
  • Detailed Energy reports and analysis
  • more versatile remote sensors

The big disadvantage of the Ecobee versus nest is the Nest learning function. I can mitigate that however by simply using the app to turn settings down while I am away. The “c wire” issue was a big deal for me since I have an older home without a c wire. Both units can operate without a c wire but it is how they do it that matters. Nest uses a trick called power stealing that can cause problems with your HVAC unit. Ecobee, on the other hand, comes with a power extender kit (PEK) that includes the extra wire needed and is easily installed out of sight near the furnace control board. The PEK Kit creates no interference with your HVAC controls.

Ecobee PEK kit – 4 wires in, 5 wires out

The remote sensors are a funny subject because I debate if they are really necessary. I could, theoretically, put one in my son’s room where I know it is colder in the winter and hotter in the summer. However, if the airflow to that room is poor, it will simply try to overcompensate by running the system longer and making the rest of the house too hot or cold. I could then add another sensor somewhere else and the thermostat will average the three. That could work, however, the remote sensors would have to be strategically placed so as to get an appropriate average temperature within the house, and in the most used locations. This leads to the advantage of the Ecobee sensors versus Nest sensors. The Nest sensors detect only temperature, while the Ecobee sensors detect both temperature and motion (occupancy). This is a very notable exception when considering the use of remote sensors.

The home report and data analysis function of Ecobee is a no brainer. It keeps 18 months of detailed charts for temperature, motion, and weather. For energy reports and analysis, it has a “Home IQ” function that is accessible online. As an engineer by trade, I love this. The Nest has improved its data analytics somewhat, however, it is nowhere near the level of Ecobee.

So I chose the Ecobee over Nest primarily due to preferences and my situation, but the Nest is still a great smart thermostat. In most cases, either one will suffice and provide you with additional energy savings while allowing you to control your system remotely.