We wanted a new thermostat for several reasons. The old Honeywell was working fine but it had several deficiencies. First, it was too easy for our grandson to change the settings. And the display was hard to read unless you stooped right in front of it. And the programming was a nuisance.
Searching for a thermostat with screen lockout we discovered that none of the good ole Honeywell residential thermostats have this feature. So we moved-on to almost-as-good - almost-as-old Emerson which has this feature on most of their residential products. Out utility company offers a $25 rebate on programmable thermostats and a $100 rebate on WiFi thermostats. With a Prime Day price of $75 this thermostat is basically free. However we were concerned by all the complaints about setup and network problems. So here is what we found.
The good -
1) Excellent manual controls and screen visibility, copied from the refined design of the legacy Emerson line. Most other WiFi thermostats have too much screen clutter in the attempt to eliminate buttons. Old-fashioned buttons really are better for the most common functions even if they don't look stylish.
2) You can control almost anything you want from your smart phone - after you complete setup.
3) You can configure this thermostat to work with almost any kind of HVAC system.
4) You have plenty of flexibility to create multiple programs with as many or as few schedule steps as you wish. For example you can have separate schedules for when you are home, when you are gone temporarily, when you are gone for months at a time. Some reviewers have complained about the difficulty of programming your schedule. Maybe Sensi have improved the app, but I found it reasonably easy to program, given the flexibility.
The bad -
1) The WiFi setup is very finicky. Were I not an engineer with many years of experience with communications equipment I might well have floundered. Common security features in WiFi routers can defeat your efforts. I would note that I recently installed a smart sprinkler controller that is completely programmed from my smart phone and has full remote access capability. WiFi setup was a breeze. I did not have to touch my WiFi router configuration at all. Sensi could do a lot better.
2) The manuals. Yes Sensi, some people do read manuals. Once you get past the simpleton stuff yours are rather poor. "See the App" (which has limited help on some topics) is not a good answer. Things like a list of the menu options and what they do - would be very helpful. The other Emerson thermostats have good manuals - so should yours.
3) Don't bother to call Sensi tech support. You will spend a lot of time on-hold and you might never actually talk to a human. And the support web site was almost as slow. The information is there but you have to be a pro to understand the more detailed stuff. Sensi needs to beef-up their tech support and/or produce a good tutorial on how to connect to a WiFi network. And if they had to write a good tutorial, they might improve their software to make things easier for their customers.
4) I found it necessary to change almost every default setting. Many of the complaints about the performance of this thermostat, arise from not bothering to check every last setting in the app. Better defaults would result in fewer complaints. This problem is confounded by lack of a list of menus and options in the user manuals. If you do not browse carefully through the app, you might miss the setting that you find most annoying.
5) You can control virtually everything else but not the fan schedule. A simple "Fan On or Auto" check box in each schedule step would be great.
The gory details -
If you have read this far, you might want to benefit from some of my experience setting-up this device for my network.
1) First let me explain my network setup. Basically my network has a less-trusted domain and a more-trusted domain. In the less-trusted domain sit my smart TVs, Game controllers, a laser printer that anyone can use, VoIP and media gateways, smart home sprinkler and thermostat controllers, etc. In the more-trusted domain sit my server, laptops, a color laser printer, and a very few other devices.
2) Between my cable modem and my less-trusted domain sits a simple but bullet-proof Ubiquity firewall router/switch. Hanging-off the Ubiquity switch in the less-trusted domain, are a VoIP gateway, a WiFi router/switch, a printer and a guest Ethernet port.
3) The WiFi router/switch serves as a second firewall between the less-trusted and the more-trusted domains. The WiFi hub has both 2.4 GHz and 5 GHz channels, with separate private and guest access, for a total of 4 SSIDs. The router steers the guest SSIDs to the less-trusted domain and the private SSIDs to the more-trusted domain. The private and guest SSIDs have different WiFi access codes (passwords) so both domains are "secure" (in the WiFi sense).
4) By default the guest WiFi clients cannot see each other on the less-trusted domain. This is a common security feature in WiFi routers that support guest access. And it is one of the features that trips-up installation of the Sensi thermostat, but not my smart sprinkler controller.
5) Observing the network interaction between the Sensi app on my smart phone, the Sensi thermostat on the wall, and my WiFi router, at some times the app and the thermostat are operating point-to-point over the WiFi and sometime via the router. So-far so-good. This is expected behavior. However some of the router traffic uses LAN (Layer 2) addresses and some uses IP (Layer 3) addresses. This mixture can mess things up if the network is not configured exactly as the Sensi software developers expected.
6) Sensi should test with other common network configurations. As I mentioned my brand X sprinkler controller does not suffer from these peculiarities. If Sensi invested more money on software engineering and testing with different network configurations they could save a bundle on support costs and customer returns.
My recommendations -
1) Configure your smart phone to use the same WiFi SSID that you want to use for your Sensi thermostat.
2) Be sure this SSID is only available for 2.4 GHz.
3) Go through your router settings to ensure that every WiFi client of this SSID has unrestricted (LAN as well as IP) access to every other client of this SSID.
4) Run the Sensi app through the complete installation and registration process.
5) After everything is working you can restore your normal network configuration in your router and smart phone. Do not change the SSID for the thermostat.
6) If you need to change the SSID for the thermostat later, go back to start. Reset your thermostat and reconfigure your network. Rinse thoroughly and repeat as often as necessary.