I’m new here and also new to domotica. Currently I’m interested in picking up a project in our shared office building. But since I’m a rookie I wanted to check in with you guys so see if I’m even close in going into the right direction
Background
I’m in a share office building with about 14 people, 12 rooms, 700m2. We annually use about 4.000m3 of gas. Which feels like quite a bit to me We have two thermostats, one for one room and one for the rest of the building (separate boiler). So it’s like one switch controlling the whole building. The rule was to close the radiator valves when you go home. But in practice, no one has done that in the last 10 years. (people, am I right?)
To make things worse within bussiness hours (when the thermostat is programmed to hours) only about 1/3 of the people are present. But all the rooms are heated. Better yet, one person often comes in at night to work or in the weekend. So the entire building is heated for one small space.
Alright, this ticks me off. This is just ignorant, wasteful and not durable.
Outline
So I wanted a way to control the boiler and the radiators per room. I’ve came up with the following list and thoughts:
To start with the brains. I would need a Raspberry Pi to run HA
Each radiator should have a wireless thermostat valve.
There are about 40 radiators (indication from memory)
I was thinking of SEA801-ZIGBEE Programmable Thermostat if it will be a low budget. Or Tapo if there is more budget.
It would be nice to be able to manually override it if the system goes down.
To connect all the TRVs I need a ZIGBEE gateway.
I don’t know how many. The building is about 50m deep and it’s a 70yo concrete building. I guess this would be trail and error if I have to figure it out.
I don’t know the model, but as a side not I’ve read some are limited to their own brand. And since I want to expand in the future I want an open one.
Wall panels to control the room’s temperature
I was thinking of going for M5stack M5Paper screens. Since these have wifi and temperature sensors.
I see you can program apps for them with M5Stack’s UI Flow online. I’ve read some mixed results, but I hope a simple program would work. To start with I would need to toggle on/off, set temp and after 17.00 bump an on-timer by 4 hours.
I hope I could create multiple screens so I can add more functionality. Like push messages from HA and other info fields I can update from HA like the wifi password
I’ve read mixed results, so I hope I can make this work with this plan.
Controlling the boilers
Now, I’m completely in the dark on this one. I think our simple programmable Honneywell thermostat simply sends a high (short) signal to the boiler. So I was thinking of adding a ZIGBEE relay to the terminals of the boiler that goes to the (old) thermostat.
Gatgets
I think it would be interesting to add an outside weatherstation to log the behavior.
Thought, could I monitor and log gas consumption?
Software outline
I was hoping for the following
User enters the room within business hours
Toggles the on button on the wall panel
M5Paper sends signal to HA
HA sends signal to the four valves and sets the temperature.
HA checks if one of the other rooms is on, if not it turns the boiler on.
After 17.00 the room turns off and the boiler turns off
If the user comes in outside business hours the system does the same, but instead of setting the off command to 17.00 it sets the off command four hours from now.
For the rest, the software part is still a complete mystery for me But we’ll cross that bridge when we get there. The hardware is critical for the base.
The question
As I said I’m a complete rookie, that only spend two days googling on the subject. Since I’m going to ask the owner of the building for money for the hardware I want to know if I’m in the right direction. So if you can please give me some thoughts and feedback on this plan. Do I have all the parts needed or am I missing something.
Hi @AllHailJ, thanks for your elaborate questions.
Have you checked with other tenants to see if they want this as well? Will make convincing the landlord easier if more people want it.
Ah, you have experience with this I’ve checked with about 50% of them. They seem happy with the idea of saving money. I know I need their support, I’m hoping the get the landlord to pay. (But I think we could also pay it our selves and earn it back in a few months )
Have you considered occupancy sensors to allow automations to control without intervention?
You mean like phone locations or IR movement sensors? Yes I have, but I’m sure this would lead to too much resistance. First step is to roll it out and make it feel “natural like the old ways”. I know these people well enough that the system should feel low-tech. Behind the scenes could be high-tech, but for them is should feel simple and low-tech. That’s why I want small screens to feel like old thermostats they are used to. Later we could move a step forward and add movement sensors. For my office I’ll add my phone location (but only if no other user account can see this in the HA dashboard)
What automation do you need to insure the building does not freeze?
I thinking of having a minimum room temperature for each room with some logic in combination with the current outside temperature. I’m not sure yet. I think I’ll also enable the ability to turn on the radiators based on an outside temperate.
Who maintains and monitors the system?
I will do that myself for the first year. I’m thinking of asking for a little fee after that IF we save a considerable amount of money. And, yes, this will be explained in advance.
And most of all I’m curious if my plan for hardware is complete and correct. I’ve only “researched” it for two days
This will be costly. Assuming all your TRVs are Zigbee battery powered devices (most radiator valves I’ve seen are), they won’t repeat for each other so you’ll need a repeater infrastructure to get your signal around. Zigbee is good for about 100 meters line of sight with no obstructions. A 70 year old concrete building is a hella obstruction so assume your signal is gonna SUCK. You’re going to need a LOT of repeaters read: mains powered zigbee devices So from wherever you put your HA install and the zigbee stick, assume you’ll need a zigbee plug or wall switch every 15 or so meters in every direction. (At the average cost of about 30 euros per unit.) so figure that into your final cost calculations.
Personally, while i can understand your frustration - this is all going to come down to what @AllHailJ says… If nobody else is interested you’re going to be screaming into the wind here. You’re better off doing your own install and learning the nuance before trying to push it onto a group. This will be very expensive to get wrong and there’s a lot of ways you can go wrong here.
This will be costly. Assuming all your TRVs are Zigbee battery powered devices (most radiator valves I’ve seen are), they won’t repeat for each other so you’ll need a repeater infrastructure to get your signal around. Zigbee is good for about 100 meters line of sight with no obstructions.
Today I’ve ordered one cheap TRV and a Zigbee WiFi Gateway. I’m going to play with it for a bit first. Maybe see where the bottlenecks are for which radiator and distance. I have a pretty good guess since I’ve also redo all the network and WiFI accespoints this year with UniFi gear.
Also since you mentioned wifi. Good strong Wifi will hinder Zigbee - 2.4 Ghz works on the same radio spectrum. Wifi absolutely kills Zigbee. Review and understand this article… ZigBee and WiFi Coexistence – MetaGeek Support I had to lock my Unifi install to use channels 1 and 6 and avoid 11 so I could focus on Zigbee channels in that space. Good luck
Don’t just block - evaluate your install, figure out what’s being used and then setup a planned config to cut a hole in your network for Zigbee. I USUALLY use channels 11/11 for my stuff (if you use channel 11 in both Zigbee and Wifi 2.4G they don’t overlap - different naming schemes) but my neighbors abnormally strong directional wifi antenna pointed directly at my house is preventing that. Taking out your neighbors infrastructure is generally frowned upon around here.
In the boiler room, you should use a far more reliable and controllable system, like an industrial grade programmable logic controller with high reliability relays… wired network connection
You should also have a failsafe for the heating system, that will ensure the building has heat and will not drop below a certain temperature if your zigbee network goes down, or if your HA instance crashes. This can loop into the thermostats and the heating PLC as a secondary on trigger.
Right, did not think of that. I don’t think for the first step I’ll go with a rugged PLC right away. But that makes me think of going entirely wifi free and, indeed, add some sort of micro controller with a relay. If it has not received a command for more that, say, 24 hours it turns off the relay and falls back on a old thermostat. Yeah, kind of gibberish I know, I’ll have to process this feedback : )
Right! Of course… Hmm, I could keep the old/current thermostat connected and set it to kick in below, say, 7 degrees Celsius
I’ve checked with about 50% of them. They seem happy with the idea of saving money. I know I need their support, I’m hoping the get the landlord to pay. (But I think we could also pay it our selves and earn it back in a few months 
I USUALLY use channels 11/11 for my stuff (if you use channel 11 in both Zigbee and Wifi 2.4G they don’t overlap - different naming schemes) but my neighbors abnormally strong directional wifi antenna pointed directly at my house is preventing that.