My dream thermostat (2024)

You want home assistant, as other comments have noted.

I have a reasonably complex set of behavior set up. I live in Bend, Oregon at 4000 feet. This is somewhere with hot sunny days, cold nights, and sometimes a lot of smoke. The effect on the interior of the house based on upcoming weather is highly predictable.

My rules look something like this:

If tomorrow's high temperature is above 85, then as today as soon as outdoor temperature drops below indoor temperature, open all the windows and turn on the attic fan until either interior temp is below 62 or outdoor temp rises above indoor, whichever comes first. Unless the AQI outside goes over 100 for more than 2 minutes, in which case close all the windows and turn on the fan/AC to clean the air. All the while, if the house rises above temperature X, cool it to temperature Y.

Additionally, the upstairs heatpump is located in an uninsulated attic, which in winter means that heating is somewhat inefficient and we want to run it a minimal count of times to avoid warmup periods. So we program in our own hysteresis, so that there's a 6-degree difference between when the heat kicks on, and when it turns off.

No one is going to make a dream thermostat that meets your needs out of the box for you, because no one else has your local needs. The best you can do is give yourself the tools to make your reality how you want it.

Am I the only one who naively clicked on all the buttons hoping to see them flick? :)

I want the UI of an old Honeywell mercury switch thermostat. Heat/Cool mode switch and dial to set the desired temperature. That’s it. Absolutely simple to understand and operate.

I just want a thermostat that gives me the option to specify that I want it to maintain a target temperature, and have it automatically switch between cooling and heating.

The one I have in the apartment I’m renting only gives Cool vs Heat. With Texas being as finicky as it is this time of year, the temperature swings from frigidly cold to swelteringly hot day to day, and with my ADHD and lack of connection to my body, I find myself wondering why I’m feeling run down and mentally foggy, and then I realize it’s because I had to switch to Heat yesterday (because the house dropped down to 60F) and today the apartment is now at 85F, and I’ve been progressively overheating for the past 5 hours or so.

You could easily make that. Thermostats are very simple concepts. Basic A/C systems are 4 wires. Power, heat, cool, fan. If you want to cool the house, you connect power to "cool" and "fan". For heat, connect "heat" and "fan". If you just want to move air, then just connect the fan. Throw in some hysteresis so you don't short-cycle the compressor. With a raspberry pi, temp sensor, screen, and a relay block (the voltages are too high for a pi), you can probably build this in an afternoon/weekend.

If you have heat pumps or a multiple zone system, or a few other things they can get more complex, but they still aren't super complicated.

Personally my dream thermostat would be Amazon’s smart thermostat, but with a firmware that allows for local control by home assistant.

Here’s why I think the hardware is so great:

- Simple, high-contrast temperature display (7-segment led)

- Just a few buttons to override temp/mode manually

- Reliable sensor (it’s made by Honeywell)

- Nice industrial design (doesn’t get in the way)

- Low price point (got it for $49)

I really wish someone would find a way to unlock their firmware. I tried to mess with it and figured it did MQTT (yay!) but it does certificate pinning :-/ I even opened one up but couldn’t find an easy way to dump the firmware off of its i.MX chip.

What I want is a thermostat has basic controls on the device such that it can do the basics (heat, cool, circulate air, hold temperature at setpoint), but also passes on all the wire states over either wifi, zigbee, or one of the other home automation standards so that I can make arbitrarily complex control boards and routines through homeassistant.

This probably exists for the really basic 4 wire versions, but I have a more complicated 8-wire Lennox thermostat and I haven't been able to find something like this.

I think this is already the "standard" interface for physical thermostats in the UK - the house where I was growing up in the UK, 4 timers (that can be selected based on "day of week"), a "1 hour boost" button, and a whole system "on/off".

This was at latest mid-90s, so not exactly "high tech". I don't think it's uncommon, as both random rented student house and the first place I rented while working had pretty much the same thing (though I think the student house only had 2 timers and no "day" functionality?). They didn't have air conditioning though, as that's not common residentially. And unless the allowed variance is also really wide (probably too wide for comfort in some situations), I don't really want the "same" temperature to be used for heat and cooling.

I'm surprised how many people I know IRL in the states that think this sort of thing is some fundamental tech limitation - like you need the latest fancy "smart" thermostat when 99% of what you will actually use it for is just "not the cheapest-possible" dumb one.

My house came with a Nest installed and I think it looks cool so I left it in but never gave it the wifi password and turned off absolutely all the crazy "smart" features it had. Now it's a really neat looking dumb thermostat and I want nothing else.

I think you want Home Assistant. Now we ask, which thermostats let Home Assistant program them without cloud connectivity? I have no idea, but last time I looked, it was a rabbit hole.

Piggybacking on this, I just want an alarm that I could tell “not tomorrow please, I’m off work. But keep the schedule otherwise, ok?”

Apparently that’s touch to ask in 2025.

If you have any familiarity with basic electronics at all, I strongly recommend building your own thermostat. It's very easy to connect a few relays and a temperature sensor to an off-the-shelf microcontroller. Give it any interface you want. Mine is an ESP-32 with a simple API that I control from a little web app or some basic push buttons on the thermostat itself in case the network is down.