I have chosen to split my files up, therefore my climate components are defined in a separate file called /climate/generic_thermostat.yaml.
This means I can use one of the Sonoff switches, which has the benefits of an integrated mains to 5V power supply and comes already housed in its own case. Select the first climate entity in the entity box, in this case I chose climate.downstairs. With the thermostats removed, the two relay switches in the Sonoff are connected to terminals 1 and 2 of the junction box. A full HVAC system also features the ability to cool the home by means of cold air. When one switch is turned off, the event will check if the other two switches are both in the off state using the and condition. You will need to assess how your own system is configured and apply the information that is relevant. We will create the cards using the UI editor and the built-in thermostat card. In system that uses a boiler to heat multiple zones there needs to be a thermostat and timer for each zone. In order to add all of the YAML files within this directory, we need to add the following to our configuration.yaml file.
If you do not want to use this feature, just exclude this line of code. It also sends an on signal to the boiler. Home Assistant can control the relay module and read the temperature from the single module when using Tasmota. How To Flash Sonoff Tasmota With An Arduino Uno And ESPTool, Home Assistant Automation Tutorial For Dummies. Thanks for visiting and taking the time to read my post, dont forget to check out some more cool articles! The thermostat will send on on signal to either the AC unit or furnace depending on whether the measured temperature is above or below the set temperature. Now we can enter the climate automation rules in our climate_rules.yaml file. I will create a new tab called thermostat for the cards but you can put them anywhere you like.
We can create the lovelace cards and finally test our our new thermostat!
In this section I will cover the easiest method of replacing the old thermostats, which will probably be applicable to most folks wanting to build a DIY thermostat. All we need to do in order to connect this to Home Assistant is replace the thermostat with a smart relay switch and give the smart relay a power source. Now that we have taken a detailed look at all the hardware and covered a variety of possibilities with the configuration, we are ready to setup Home Assistant.
Now we can enter the first instance of generic thermostat in our generic_thermostat.yaml file. In my case I have two zones, upstairs and downstairs. If you wish to convert a system like this, the easiest way is to leave your zone controller installed and simply replace the thermostats with relay switches. Please note that your system may still differ, so it is important that you use this information for educational benefit only. The thermostat/timer modules have been removed and replaced with the Home Assistant components.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'siytek_com-mobile-leaderboard-2','ezslot_16',164,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-mobile-leaderboard-2-0')}; I have also added a standalone AC unit that I will put in the master bedroom, which can be switched on and off with a smart plug. When the thermostat turns the zone valve on, it opens in order to allow the hot water to flow to the radiators downstairs and it also sends a signal to the boiler to switch the heat on. The cold_tolerance parameter is the value that the temperature must drop by before the switch is turned on. I wanted to minimise the work required to put the system back to how it was in the event of selling my house.
Time to open that bottle of bubbly and celebrate whilst you forget about your HVAC system. Then we need to create a new directory and new YAML file. If you would rather just keep everything in your configuration.yaml file, simply enter the code after climate: with one level of indentation. As this thermostat will be used for cooling and not heating we need to change the ac_mode to true so that the switch is enabled when the heat is above the setpoint. This step is important and should not be skipped or you may cause damage to your HVAC system. This is a similar to the method to repurposing the existing wiring, however we will not make any changes to the existing wiring and instead we shall locate our temperature sensors near a USB power source.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[300,250],'siytek_com-sky-2','ezslot_26',169,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-sky-2-0')}; This is the route I have chosen and the reason being there is already power in this location. WARNING: These cables carry the full mains voltage and could give you a LETHAL electric shock. However there is a limitation, it only supports a single zone of either heating or cooling. Lets take a look how to do this, here is the main thermostat in my house that controls the downstairs heating zone. This serves no purpose in my installation but is representative of the fan found in ventilation type systems. Therefore the three rules we need to create are as follows. I have a dual zone system with a hot water boiler and will be adding a small standalone AC unit in the master bedroom controlled by a smart plug. All zone valves in the system are connected globally to the boiler so that if any of the valves are open, the boiler will be on. You may find additional wiring here for AC or the fan, in which case you can also connect these to separate relay switches for your AC and fan functions. DO NOT attempt to modify your HVAC system if you do not fully understand what you are doing. This is the method that I would most recommend in order to minimise exposure to mains electrical current. You will need to have Home Assistant installed and configured, plus your devices added and recognized as entities. The hard bit is complete and now the fun part! You could of course adopt this same technique with your own system. The green lines show data or a control signal.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'siytek_com-netboard-2','ezslot_21',173,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-netboard-2-0')};if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'siytek_com-netboard-2','ezslot_22',173,'0','1'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-netboard-2-0_1')};.netboard-2-multi-173{border:none!important;display:block!important;float:none!important;line-height:0;margin-bottom:15px!important;margin-left:0!important;margin-right:0!important;margin-top:15px!important;max-width:100%!important;min-height:250px;min-width:250px;padding:0;text-align:center!important}. As I have a dual zone heating system I have two thermostats, one for upstairs and one for downstairs. You do not need to worry about the complexities of the zone control system.
There are many different configuration of HVAC system so you need to gain a full understanding of your own system and how it is configured. In order to replace the existing thermostat, we simply need to connect these wires to a relay switch that can be controlled by Home Assistant. All of my devices will be flashed with Tasmota and controlled in Home Assistant using MQTT. The only downside to this is we cannot incorporate our temperature sensor and relays into a single module as it is almost certainly the wrong location. We can use a smart switch like the Sonoff basic to control the signal to the boiler/furnace. This will ensure that if for some reason the fan is turned off, the AC and heating zones do not continue to run. As there are many different possible configurations we will take a look at things from a more generalised perspective. Firstly lets summarize the rules that needs to be created. Personally I am very pleased with the thermostat integration in Home Assistant, so much so that I was inspired to make such a long tutorial.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[300,250],'siytek_com-small-square-2','ezslot_33',186,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-small-square-2-0')}; It would be great to see an integrated thermostat that can handle multiple zones and both heating and cooling in a future version of Home Assistant. Dont worry if your system is different, the aim of this tutorial is to give you a full understanding so that you know how you should configure your own system. If in doubt, stop and seek expert assistance from a qualified HVAC engineer. I agree that the Google Nest looks beautiful but if you really want to wow your friends, why not mount a tablet to the wall and make an awesome looking dashboard! Next we need to specify the switch that will control the zone valve for downstairs (or just the boiler/furnace in a single zone system).if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'siytek_com-portrait-1','ezslot_23',177,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-portrait-1-0')}; Then we need to define the sensor that Home Assistant will use for the temperature within this particular zone. When either of the thermostats makes a call for heat, the switch inside the thermostat is closed and the current is delivered to the corresponding zone valve through terminals 1 and/or 5 of the junction box. This means that, at zero cost to you, I will earn an affiliate commission if you click through the link and finalize a purchase. We need to change the name to Upstairs and also we need to use switch.upstairs in order to control the upstairs heating zone with this thermostat. These can be powered from any 5V source, such as USB or a battery. I have a detailed guide that makes this very easy and you can build one for around the price of a beer! Some systems only have the ability to produce heat, which include all boiler systems and ventilation systems that do not have an integrated AC unit. The on signal from each thermostat is sent to a zone controller. We can achieve this using the and condition. For this tutorial we will assume that you have Home Assistant up and running already. modification to your HVAC system without consulting a certified engineer. This is how the Nest thermostat delivers power to the pretty looking wall control unit.
Then we need to create a new directory and add a new YAML file. This is a safer option compared with running a mains power cable and using a 5V switching power supply module. In order to feed the temperature to Home Assistant we can use a seperate low voltage system consisting of a Wemos D1 Mini and DHT22 temperature sensor. This card will contain all of the entities used in our thermostat system. It should give you enough of an idea how to design your own system.
To start with I will give some examples of parts required. This is only the starting value when Home Assistant loads and will change when you adjust the temperature slider. Lets recap on the devices we will be using. Something beyond the ability of a commercially available thermostat! Home | Privacy Policy | Cookie Policy | Contact. The mains power is globally connected to both zone valves and the boiler/furnace using terminals 2 and 3 of the junction box. Now that we have completed the first thermostat, we can make a copy of the code below on order to make the second instance for the upstairs heating zone. It is important that you understand how your own system works and then apply some of the ideas here.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[300,250],'siytek_com-sky-1','ezslot_25',172,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-sky-1-0')}; When the thermostat wants to switch the boiler on, its internal relay closes and the mains current travels along the black wire to the boiler/furnace, switching it on. All the code is finally complete so we can go ahead and and save the YAML file. There are just two wires connected to the back and if we short these wires together, the zone will turn on. I will also cover an alternative method that I will be using to build my system, primarily to give an idea for an alternative method. If we take the unit off the wall we can see that the wiring is very simple. As this zone is for the downstairs heating we will set this to false. Firstly we will look at the most basic system for heat only. The disadvantage is of course having the change the battery. Both the Wemos D1 Mini, temperature sensor and relay module could be all be powered from 5V sourced from a battery. Therefore for this solution we will use a seperate D1 Mini for each temperature sensor and locate them near the existing thermostats.
In a single zone system it would work in exactly the same way, however the zone valve would be omitted and the thermostat would simply control the boiler/furnace heat directly. There are some benefits to this method at the expense of a slightly more complex installation.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'siytek_com-small-rectangle-1','ezslot_29',165,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-small-rectangle-1-0')};if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'siytek_com-small-rectangle-1','ezslot_30',165,'0','1'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-small-rectangle-1-0_1')};.small-rectangle-1-multi-165{border:none!important;display:block!important;float:none!important;line-height:0;margin-bottom:15px!important;margin-left:0!important;margin-right:0!important;margin-top:15px!important;max-width:100%!important;min-height:250px;min-width:250px;padding:0;text-align:center!important}. If you have a wall socket nearby you could run the power from there to the thermostat. First lets take a recap on one of the systems described earlier, the system that is currently operating in my house. First we need to define the platform as generic_thermostat and give it a name. If you want to integrate your relays and temperature sensor into your existing thermostat wall box, you can use a 5V relay module connected to the Wemos D1 Mini that you use for your temperature sensor. For references, the names are as follows. Therefore I will install two temperature sensors. However I will include all of the additions including the Home Assistant code and setup for fan control for the benefit of my American friends who are more likely to be using a ventilation based system.
If you have a furnace and air ducting then you will need an additional relay switch to control the fan. From the overview page, click on the three dots and then configure UI in the top right-hand corner of the page.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'siytek_com-portrait-2','ezslot_24',184,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-portrait-2-0')}; This will switch on the UI editor mode. without turning off the main power supply, This step is important and should not be skipped, quick and easy guide to a heat-only thermostat, Single zone heating with furnace and air ducting, Multi zone heating with furnace and air ducting, Single zone HVAC with furance and air ducting, Multi zone HVAC with furnace and air ducting, Single zone with Sonoff Basic, Wemos D1 Mini and DHT22, Single zone with Wemos D1 Mini, DHT22 and relay module, Dual zone with Sonoff Dual R2, Wemos D1 Mini and DHT22, How to automatically dim the lights using home assistant when watching a movie, How to simulate a sunrise with Home Assistant, How to control all of your smart devices with your existing dumb light switch, Wemos D1 Mini and DHT22 temperature sensor, detailed guide on how to set it up to auto discover in Home Assistant, build a temperature sensor for Home Assistant using a Wemos D1 Mini and DHT22, One temperature sensor for each additional zone, One relay switch for each additional zone, One relay switch for each air duct damper, Any boiler system or ventilation system with no integrated AC, Sonoff Dual R2 two switch relays that control each heating zone, Smart Life plug to switch on and off a standalone AC unit, Smart Life plug to switch on and off the fan (not applicable to my system, but included for those who will need it), The heat must be disabled if the AC in enabled, The AC must be disabled if the heat is enabled, The fan must run if either AC or heat is enabled, The fan must stop if neither the heat or AC is enable. Finally we need to add a third instance of the thermostat in order to control the AC unit in the master bedroom.
This tutorial aims to cover all of the details for designing your own Home Assistant based HVAC control system, including multiple zones and air conditioning. Now we have completed all of our instances of the climate integration, go ahead and save the YAML file.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'siytek_com-netboard-1','ezslot_20',180,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-netboard-1-0')}; There are some important rules that we must setup in order to make sure our system functions safely and that no damage is caused. Thats it, we are all done! The zone controller switches on the AC unit, furnace, air duct dampers and fan depending on the requests it receives from each thermostat. Copyright 2022 Siytek. Note that there is only a live and neutral mains connection to the boiler and not to the thermostat. The system is very simple, the timer thermostat module has a live incoming cable connected to a switch shown in brown. The thinner red and black lines show the 5V positive and negative connections. An common example would be independent zones for the upstairs and downstairs areas of a home. You could either just run the USB cable directly or if you are willing to invest the time, you could hide the wire inside the wall. The fan will only be turned off if both other switches are off. We must create a separate event the fires for each heating zone switch and the AC switch.
Another way to wire in to your existing system is to connect your relay switches in the location where the existing thermostat wiring terminates. I also have an awesome tutorial on how to build a temperature sensor for Home Assistant using a Wemos D1 Mini and DHT22, so go check it out if you still need temperature sensors. Some systems use return air ducts, which have been omitted for clarity. My suggestion here would be to use a Wemos D1 Mini connected to a DHT22 temperature sensor and a relay module. Give the entity card a title, I called mine climate sensors. The dual zone system looks a lot more complicated in the diagram, but it is quite straightforward in its operation. The radiator nearest to the thermostat does not have a local thermostat as the room that it is located in is used by the main thermostat to set the global temperature. In my system there are two zones of heating and one zone of AC (the standalone AC unit in the bedroom). All rights reserved. This would make the wires in the existing thermostat into a live an neutral, which you could connect to a 5V switching power supply module to run your Wemos D1 Mini. The hot_tolerance parameter is the value that the temperature must increase by before the switch is turned on. If you need to configure a Sonoff device for Home Assistant, I would recommend flashing it with Tasmota and setting it up to auto discover.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'siytek_com-narrow-sky-2','ezslot_19',175,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-narrow-sky-2-0')}; As previously mentioned we are going to create a system capable of full HVAC control. In system that uses a furnace to heat or cool multiple zones there needs to be a thermostat and timer for each zone. This is relevant for a thermostat setup as a heater. There is also a desk fan connected to another smart plug shown in dotted lines. if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'siytek_com-medrectangle-4','ezslot_3',153,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-medrectangle-4-0')};If you are new to Home Assistant and dont have any experience with YAML, I would recommend checking out one of my other tutorials first.
This means that if either zone valve is open, the heat will be switched on. Now we have entered all of the code for our first thermostat instance and the completed code should look like this. The wires that connect to the back of the thermostat are for switching only. You would need to install your relay module in the place where the wires terminate and then reconnect these wires to the mains power supply.
We need to change the name to Upstairs AC and also we need to use switch.ac in order to control the AC unit with this thermostat. I will be using the Sonoff Dual R2 as it has two relay switches and I can use one for each zone. We also need to add a rule that will switch the AC and both heating zones off if the fan is turned off manually. Congratulations for making it to the end of this huge tutorial! As the DHT22 has a precision of 0.1, we can set it accordingly. if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[300,250],'siytek_com-medrectangle-3','ezslot_6',152,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-medrectangle-3-0')};Youll have something more unique and unlike an (expensive) smart thermostat, you will be able to control your whole house from the dashboard! You can omit any of the elements if it is not applicable to your configuration. It is very easy to make and can be powered from a USB connection. The thermostat will send on on signal to the boiler if the measured temperature is below the user desired temperature.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'siytek_com-leader-4','ezslot_14',188,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-leader-4-0')}; The boiler heats the water in the pipes, which is pumped to the radiators in each room.
For now I have the modules attached to USB chargers, which are plugged in to sockets near the old thermostats.
The initial_hvac_mode parameter is the mode that the thermostat will be set to when first loaded. It is not actually required for functionality but I would highly recommend it in order to check everything functions as expected. The most important thing to understand here is the inputs and outputs required for Home Assistant, which are common across all types of installation. The following diagrams are just ideas to help you understand the kind of system that exists. A huge benefit of using Home Assistant as your smart thermostat is that you can easily integrate a standard dumb AC unit using either a smart plug to switch the power or an IR blaster if the unit has a remote control. This thermostat has the timer integrated and has switch contacts on the back that open and close to turn the zone valve on and off. The thermostat also controls the fan and can be set to on or auto depending on user requirements. Enter the name you wish to be displayed on the card under in the name box. Disclosure: Some of the links on this site are affiliate links. The system consisting of a single thermostat that either heats or cools the home depending on the desired temperature vs the actual temperature. In a system consisting of a boiler, valves are used in the pipework to stop or allow the flow of hot water to designated zones.
The target_temp parameter is the temperature that the thermostat is trying to achieve. If you would rather just keep everything in your configuration.yaml file, simply enter the code after automation: with one level of indentation.
These are only suggestions and you can use any sensor or switch that you like, so long as it can be recognised and controlled with Home Assistant.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[300,250],'siytek_com-large-leaderboard-2','ezslot_5',156,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-siytek_com-large-leaderboard-2-0')}; Please do not attempt to make any modifications to your HVAC system unless you are absolutely certain you understand what you are doing.
I would recommend locating it somewhere near to the original thermostat, particularly if you are using a boiler type system.
A single or multiple units can be used either in a single zone system or grouped to match the zones of a multi zone system. In most cases the thermostat wiring will terminate either at the boiler/furnace, zone valves, zone controller or a junction box. The wiring found in different systems will not necessarily be the same, therefore it is most important that you have a full understanding of how your system is wired. Switch off the show header toggle switch as it is not needed. This sensor is located in the same room as the AC unit but if you have yours in a different room, you should add an additional sensor in that room and use it instead. I have configured Tasmota on all of these devices and they are all showing in Home Assistant as entities. This also electrically isolates the control electronics from the heating system. In addition to your Wemos D1 Mini, temperature sensor and relay module, you could add a 5V switching power supply and run a power cable to the location of your old thermostat. In the entities list we need to enter all of the entities used in the system. Neutral is shown in blue, live is shown in brown but grey is also used for the zone valves.
The default of 0.3 degrees C works well with the DHT22 sensor. Why spends hundreds on a smart thermostat when Home Assistant has the power to control all of the necessary hardware and its absolutely free?! If you know the location where the wires from the thermostat terminate, you could repurpose them as power cables. I would advise that you do not attempt any modification to your HVAC system without consulting a certified engineer. The thermostat integration is well documented on the Home Assistant website, I would recommend reading about it further on the Generic Thermostat page. We can break things down into two categories, single zone and multiple zone systems.
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