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Comment by majewsky | Hacker News Reader

Just yesterday, it occurred to me that an IoT thermostat would be nice (if and only if it doesn't mean that a server failure results in me freezing). Right now, I have the choice of heating the house all day (thus wasting heat = energy = money while I'm not home), or coming back to a cold house, turning up the thermostat and then having to wait 1-2 hours until the room is pleasantly warm. (My apartment is understaffed in the heater department and I cannot change that easily since I'm renting.)

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Those have existed for years, apartment buildings are just usually cheap and lazy and don't install them.

I've got a Honeywell model [1] I can set from anywhere via an app. It also has scheduling it falls back to if I haven't overridden it via the app or faceplate. My winter weekday schedule: 66 at 6am, 62 at 9am, 65 at 4pm, 62 at 10pm.

1) https://www.amazon.com/Honeywell-Programmable-Thermostat-RTH...

ive got the same one. works great.

It's quite easy and cheap to make a wifi-connected thermostat yourself. I did it, it's great.

I made a web interface so that I can control it with my phone when I'm not at home.

It is based off an ESP8266 placed in the boiler which controls a relay to tell the boiler whether to heat or not, and an ESP8266 in my office that has a temperature probe and a rudimentary user interface, and runs a web server to allow remote temperature inputs, and controls the ESP8266-relay over WiFi.

The 3d-printed enclosure is rather coarse, but does the job: https://img.jes.xxx/1585

EDIT: Failure of the system could result in you freezing, but that's true of anything that controls your heating, and at least this is a device you understand are in control of, and it doesn't rely on anything outside your house. If it fails and you're freezing, just short the terminals of the relay while you debug it.

In cold climates, the problem with failed thermostats isn't frozen people, it's frozen pipes, which can happen when the people aren't home.

An easy way to insure against such failure is to put your homemade thermostat in parallel with an old fashioned thermostat which is set to a constant low temperature.

A seemingly common safety is to wire the custom thermostat in parallel with a simple commercial one so that the commercial one kicks in if the temperature gets too low.

If you are in Europe, you can also buy the ESP8266 from Olimex with relay, box and eventual lipo plug. You then just have to flash your code on it. Only downside is they are not properly shielded electromagnetically so they can only be sold as Kit for experienced users (as certification costs would dominate the price). Also, if your house happens to burn, you can be pretty sure the insurance companies will pin it on your uncertified DIY appliances.

> Also, if your house happens to burn, you can be pretty sure the insurance companies will pin it on your uncertified DIY appliances.

This is one thing that's constantly on my mind when toying with long-lived electronics projects. Do we know of an actual precedent here?

I don't know of actual precedent, but there are numerous examples of lipo house fires (which aren't fully covered). And semi related personal one-datapoint anecdote I've experienced water damage and robberies in the past and they were a lot more prompt to try to find loopholes to not have to pay. I can't afford to set a precedent, so I stick to fused low voltage off the shelf products.

Use an off the shelf wireless plug in switch and a Telldus transmitter then you don't do any high voltage or high current wiring at least if you are controlling a standalone heater.

I want a DIY Smart Vent to go with 3D Printer Thermostats in each room.

https://community.smartthings.com/t/smart-air-vents/4913/21

Thermostats with scheduling capabilities have existed for a long time and they don't need the internet to do it. Unless you're referring to when you're out of the house when you would normally be home?

Are there not thermostats on the market that let you program schedules? If you do want something a bit more connected, thermostats in the Lyric line from Honeywell[1] can give you things like scheduling and geofencing (e.g. "oh, you're on the way home, let me start cooling...") Of course, a geofence isn't going to function if you're offline, but the thing should definitely remember a time schedule to use as a backup when connectivity is lost.

[1] I work for Honeywell

They exist, I have one and find it useless:

When I go on vacation for a week there is no way to say "go to max energy savings while saving my pipes mode until just before I get back." I can reprogram the entire week, but then I lose what is the correct programming for normal until I reprogram it. Worse my house is uncomfortable when I get back - usually when I'm tired and want to jump into bed asap (if I know I'll get home about noon I'll look for a tourist thing to kill some time long before I get home).

I don't always have the same schedule. When I'm home sick I don't want to reprogram it. Some weekends I'm at home all day, some I'm out all day - which program is right? IoT thermostats also through privacy and reliability concerns in. The old fashioned mercury thermostats from the 1950s still work as good as new. While your IoT thermostat work next year - some do not.

All the above is made even harder because my house is headed by an air source heat pump: if I'm returning at 9pm it might or might not be better to start heating my house at 11am when the day is warmest. The algorithm depends on the weather which is best predicted the day of.

My Honeywell t-stat has a schedule and a hold function which can be either timed or permanent. If you want to lock a temperature, you can tap the hold button a couple times to set it to "permanent hold" and set the temperature to whatever you want.

Timed thermostats would probably get you 90% of the way there.

Programmable thermostats have existed for a long time and it's easy to find internet enabled ones these days.

The problem is that you're renting so you can't do any cool home automation stuff.

thermostats are trivial to change if you have any electronics or handy skills, just don't put new holes in the wall that aren't hidden by the mount plate if you're renting. It's basically like replacing the shower head while renting.

That already exists, here is a widely recommended version.

https://nest.com/thermostats/nest-learning-thermostat/overvi...

I am honestly not sure why this is getting down voted. The nest thermostat does continue to work as intended when offline. Of course you won't be able to use the app while you are away to control it.

You get timer-based units that reduce the temperature at night (optionally also when you are at work). They cover a good chunk of the usecase and will give good amounts of savings. No Internet, mobile app or machine learning needed.

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