Replacing ISY with Home Assistant – Part 1 – Preparation

This will hopefully be a short series on migrating away from my ancient ISY994.

They killed it!

I have had an ISY994 since early 2018, and it has served me well. It is the core communicator with my Insteon and Z-Wave devices. However, Universal Devices is killing it in favor of their eisy device.

Now, I have to be very clear: as a software engineer, I absolutely understand their decision. Innovating software while having to support old hardware is a painful process. However, the cost to move is making me look elsewhere.

When I originally purchased the ISY, I paid about $400 for the unit and the Serial PowerLinc Modem (PLM). Considering it has been running for 5 years, $80 a year is not bad at all. But to move to the eisy, I need to buy:

  • eisy – $290
  • Serial Adapter for my PLM – $26
  • Z-Matter USB – $126

So I am looking at about $450 for an upgrade. But some more “recent” developments make me wonder if I can do it better.

Enter Home Assistant

I do not have an exact date, but I have been running Home Assistant for a few years, and I prefer it over the ISY. The interface is newer, and the open source nature makes it a bit more reactive to new technology. Now, Home Assistant has an integration with the ISY, but the ISY’s APIs are, well, flaky. I find myself having to remove/re-add the ISY to Home Assistant, reboot the Home Assistant, and/or reboot the ISY to get it back.

With the ISY being retired, can I just replace it with the Home Assistant? Well, that’s what the prep work is about.

Requirements Gathering

Like any good project, I started by outlining some basic requirements:

  1. Insteon Support -> I have a lot of Insteon devices, mostly hardwired switches. Supporting those is non-negotiable. I have a Serial PLM, it would be nice to re-use that for communication with my Insteon devices.
  2. Z-Wave Support -> I have a few Z-Wave devices, mostly some plug-in outlets and a relay. These are currently supported via my ISY, but the antenna is weak and therefore the Z-Wave is less reliable.
  3. Standalone -> I am running Home Assistant as a Kubernetes node in my production cluster. Sure, it works, and it makes upgrades easier. Having a critical system in lab components makes me nervous, so I want to move Home Assistant to its own hardware.


Right now, I am in experimentation mode. I have ordered some parts to connect my PLM directly to a Raspberry Pi, and have started the process of installing Home Assistant on the Pi. I am also shopping Z-Wave dongles.

The next few weekends will involve some experimentation. I’m sure everyone in the house will be thrilled when Alexa no longer controls the lights…






8 responses to “Replacing ISY with Home Assistant – Part 1 – Preparation”

  1. David Pfeffer Avatar
    David Pfeffer

    You’re killing me here. I just Googled for this topic because I’m about to start the exact same transition, for the exact same reason. I was so pleased to find this multi-part series and I am now realizing you only posted this part 1 yesterday. 🙃
    I’ll comment if I find out anything useful before you post again.

    1. Matt Avatar

      Well David, I just so happen to have put the finishing touches on Part 1a:

      I’m currently waiting for some parts and some time to put my plan into action!

  2. Chris Avatar

    Long time user of the ISY and Smart Home devices. I had an Ocelot doing x10 protocol before Insteon. I am glad I found this article.. as I also don’t want to spend the money. I just installed HA in a container on my NAS not sure yet how that will affect my PLM connectivity but I will keep reading.

    1. Matt Avatar

      Running in a container comes down to making sure you have access to the hardware, which can be tricky with containers. That’s part of the reason why I moved to a dedicated hardware device (the Raspberry PI): it made the communication with the modem and Z-Wave dongle much easier.

  3. Steven Bailey Avatar
    Steven Bailey

    I develop node server plugins for UDI ISY, Eisy and you forgot about Polisy.
    If you’re a developer Eisy is a full FreeBSD frontend you can develop on.
    I have several systems and have not started with Home Assistant.

    Before finding this article I purchased a new Router from Contemporary Controls and now have a true front end webpage. Alarms, graphics and trending.

    Should be able to pull all data from UDI ISY, Eisy and Polisy. They are allowing me to be a Python Developer and i m waiting for information.

    So i will also configure Home Assistant so i can have Tuya locally with the TinyTuya module.
    I had it on UDI as Cloud API however if you read the fine print from Tuya the API is not for commercial use.
    So i wasted two years programming Tuya on UDI.

    So there cannot be “Only One!”
    And i feel the Eisy is one if not the best Frontend on the market, for developers.

    1. Matt Avatar

      Without burdening the world with the details, I’ll simply say I had some less than ideal experiences with ISY before all of this, so the forced moved from ISY to eISY was the “last straw,” so to speak.

      My overall goal was to consolidate systems, and Home Assistant has provided me with an easier path than the eISY did. I am sure that the eISY is a great tool for many, but it simply did not quite fit my own use case.

      1. Steven Bailey Avatar
        Steven Bailey

        Hello Matt,

        EISY is not that expensive. Also my ISY is still functional as is. I just spent $1095 + tax on a BASView from contemporary controls for what all home control systems do not provide.
        You’ll find many a Home Assistant customers pulling data from ISY via API. I am with my PG&E utility metering. However i haven’t taken the time to setup HA, yet.

        I don’t think anyone platform will have it all until one buys up the many.

        Additionally, If you write code, EISY with dual monitors or using Remote Desktop is a real pleasure.
        So there was a reason for it as you mentioned. You can use Python or Nodejs to write your own Plugin formally called a Node Server.
        If UDI includes on the fly trending instead of a database push, adds graphics along with its alarming then you would really have something. Especially if they add BacNet and Lon work’s protocols.

        i think most home systems are toys as i installed programmed and commissioned many a BacNet systems for the building industry. Which brought a standardization to HVAC controls and Electrical monitoring of systems.
        Home automation needs to do the same.

        A real pleasure talking to you! Please post your progress.


        1. Matt Avatar

          There is certainly a wide gap between residential and commercial systems. Universal Devices and Home Assistant are trying to fill those gaps. Again, as I mentioned in my comment, my desire to move was based on my own history with both systems and my desire to consolidate. The APIs on my ISY had a stability issues, and using HA to connect to them was not consistent. Open source will almost always be less expensive in terms of capital investment, but you invest time in setup and maintenance.

          As my system stands today, I feel like I could sell the house with the Raspberry PI and the new owners could take advantage of all that I have done. And that is truly the goal.