Is there a limit to the amount of HomeKit devices that I can add?

[applebluesman]

Hi, I am building a new home and wanted to see if there is a limited number of switches, outlets, cameras, sensors, etc. that I can add to my Homekit system before overloading the WiFi?

 

[Just_Me_D]

Not that I’m aware of, but hopefully others will chime in soon.

 

[camaroz1985]

There are limits to devices that can connect to the hubs that would interface with Homekit (Hue, Lutron, etc.), but as far as Homekit itself I don't know of any limitations. I have about 60 devices connected to mine now, that is going through several different hubs, but all are in Homekit.

 

[GarpyN]

Thanks. That question intereted me too.

 

[BravoMike09]

I have the "Homecontroller" app which reports that I have 166 devices in Homekit. Lights, switches, cameras, environmental, security, power outlets. Several bridges are used including Hue, Lutron Caseta, Arlo, Eufy, Abode, Aqara, Nest (using Starling).

I had numerous devices showing "No Response" until I upgraded my Wifi with three eero mesh routers. Now there are rarely any devices showing no response. The eero system seems to be pretty reliable. Previously I had an Apple Airport Extreme, but it was not adequate. The Apple Airport Extreme was located on the 2nd floor of a three story home. Now there is one eero on each floor.

I do have numerous Homekit issues including non responsive controls though they don't show up as "No Response." They just intermittently do not work. This seems to be a Homekit failure rather than a device failure.

For instance, I have four Opel switches using an Aqara bridge. One of the switches is six buttons and the other three are four buttons. When I open the Homekit page that shows the three functions for any switch (single press, double press, or long press), you can verify operation of that function because it will highlight when that function is activated. Apple added that feature into the page for any switch as a means to tell if the command from that switch is reaching Homekit. In about 80% of the cases the signal is reaching Homekit and that function highlights, but Homekit just ignores it.

So if the signal makes it into Homekit then why is Homekit ignoring it? I don't know but I have to assume I'm running up against the limits of Homekit. So what are those limits? Hardware? Software? Both?

This brings up several questions that I have been trying to find the answers for. I'm not sure that I will find those answers here but maybe...

Hardware limitations. The devices acting as a Homekit hub have limits in both CPU, Bus, RAM, and SSD storage.

RAM. Currently, the Apple TV 4K has the most RAM of any Homekit Hub at 4GB. I think Homepods have 1GB (I don't have a Homepod). iPads have up to 2GB depending on the model, correct me if I'm wrong. I'm sure RAM is not the only limiting issue, but if RAM is exceeded then there may be issues and numerous errors.

If local storage becomes an issue then Homekit may not be able to add or change parameters for scenes, automations, or devices. I have three Apple TVs. One 4K and two HDs. I only use two of them to act as a Homekit hub as the third Apple TV HD is located in a remote part of the house. The Apple TV 4K has 32GB of SSD storage. The Apple TV HD has 64 GB of storage. Usually the Family Room Apple TV 4K acts as the active hub while the Master Bedroom Apple TV HD is in standby. Obviously none of us has any control over which hub Homekit wants to use and Apple has not published that information. The Family Room Apple TV 4K is centrally located so it's in the optimum location to act as a hub. I recently deleted several apps off of all Apple TVs to make more storage available if Homekit needs it, but I have no idea how much storage Homekit needs.

If the CPU or the data Bus is an issue then there will be data communication errors. The Homekit apps on my iPhone, iPad, and MacBook (2017) all freeze intermittently for up to several seconds. Sometimes I force quit these apps. So it's unknown to me what is causing that. RAM, CPU, Data Bus?

All of those hardware issues may exist in not only hubs, but devices used to control Homekit like iPhones, iPads, Apple TV's, etc. If the Homekit app has to load all of that data then at what point does the data start to saturate and overwhelm the RAM?

The errors I'm seeing now are mostly unresponsive controls, and unable to edit devices in scenes and automations.

Not only do I have 166 devices, but many of the multifunctions switches have numerous automations with each switch. More data to store and use. For instance, the six button Aqara Open switch can have three automations assigned to each button for a total of 18 automations for that switch. Each automation have have an unlimited number of scenes and devices which exponentially adds to the data.

Unlike automations listed on the "Automations" page, these "Switch" automations are only shown on the pages for each function of each switch. In the HomeController app automations listed on Homekit automations page and all switch automations show up together on the same list. The automations are exactly the same. "When this accessory is controlled do this."

The limit for scenes is 100. That is the only limit to Homekit that I have even read about and I ran up against that limit last year when I tried to add scenes and got that error message from Homekit. If I remember correctly the error message actually read that 100 scenes is the limit.

I'm not sure about the maximum number of devices or automations.

So with all of the devices, scenes, and automations the data can become overwhelming to Homekit. Again, I'm not sure if that is the exact problem I'm having, but if I'm not hitting some limitation in RAM or Storage or whatever then there has to be a point where that will happen.

Anyway, I hope someone sees this and has some answers or even questions.

Thanks