Smart-i-fying my old heat pump and adding it to Home Assistant

Ever since I bought a house, I've become one of those guys. I've fallen in love with the idea of being able to control everything in my home with my voice or with my phone.

Whether it's installing smart light bulbs, Zigbee-powered light switches, or adding integrations to my router so I can keep an eye on my network status—I love having control over all the devices in my home from one place.

And that place is Home Assistant.

It's a terrific piece of software with integrations for most common smart home applications. But today, I'm taking my first step toward controlling the disparate HVAC (Heating, Ventilation, and Air Conditioning) systems in my house.

And I'm going about it in a way that's somewhat different than I first anticipated: I smartified my heat pump.

The Challenge We Face

Now, this is a Fujitsu ASU-9RLS2. It’s not a smart heat pump. It doesn’t have Wi-Fi or even a radio controller. It comes with a remote—an old-school infrared remote. And when I say “dumb,” I mean it only sends commands; it doesn’t receive them.

That means every command you send—whether it’s for cooling or heating mode, fan speed, temperature, or oscillation—is broadcast in full every time. The remote just assumes the command is received and that the heat pump is in the state you just specified.

For example, if I press a button while the heat pump is in another room, the remote turns on and assumes the heat pump is set to cooling mode at 64°F—but it may not be. That’s pretty contemptible, to be honest.

There are plenty of ready-made solutions for smart-i-fying radio-controlled or Wi-Fi heat pumps, but not so many for infrared-controlled ones—or so I thought.

Enter: Broadlink RM Mini 3

Lately, I've been trying to connect as many remote-control devices as I can to Home Assistant. That’s when I found the Broadlink RM Mini 3—a small IR blaster supported by Home Assistant and SmartIR, an extension for controlling media devices, HVAC, and other IR devices.

So how did I smartify my heat pump?

It took some experimentation and troubleshooting over multiple days, but the final result was worth it.

Step-by-Step: How I Did It

Step 1: Set Up the IR Blaster

To get started, I had to set up the RM Mini 3 using Broadlink's mobile app. Not ideal, but once it’s set up, the app isn’t needed.

• Open the app and click the "+" button.
• Choose "Universal Remote" and then "RM Mini 3".
• Walk through the remaining steps, then unlock the device under Device Settings.

I’m not a fan of embedded Wi-Fi devices, but I made an exception here. After getting it configured, I connected it to my untrusted devices WiFi network which doesn’t have WAN access.

Step 2: Set Up Broadlink Integration in Home Assistant

Once the RM Mini 3 was online, Home Assistant detected it and installed the Broadlink integration automatically. That was pretty slick.

Step 3: Install SmartIR Component

This was a bit tricky. I’d never installed a custom component in Home Assistant before.

• I followed the instructions in the SmartIR GitHub repo.
• Moved the files into the correct (nonexistent) directory—I had to create it.
• Modified configuration.yaml.

When I hit "Check Configuration," I got an error: SmartIR not found.

Turns out, I needed to completely restart my Home Assistant OS VM for it to pick up SmartIR. After that, we were good.

Step 4: Find Compatible IR Codes

The tedious part: SmartIR lists many Fujitsu devices, but none matched my model number.

So, I went through the climate codes list in the repo and tried each one until I found one that worked.

This was absolutely the longest part of the whole process.

Steps 5–8: Configure, Test, Repeat

• Step 5: Set the correct device_code in configuration.yaml.
• Step 6: Restart Home Assistant.
• Step 7: Use SmartIR widget to test the buttons.
• Step 8: If it didn’t work, go back to Step 4.

Eventually, I found a code that worked: 1287.

Some limitations:

• No vertical swing (I never use it anyway, so that's not a big deal).
• No control over “Powerful Mode”—it defaults to non-Powerful Mode.

Limitations and Room for Improvement

Because the interface is still infrared-only, the heat pump doesn’t send confirmation signals. So, we can’t be 100% sure it’s doing what we think.

But once I install an electrical panel monitoring system and integrate that with Home Assistant, I should be able to sense if the heat pump is on/off and infer modes based on power draw.

SmartIR even supports this kind of setup, too! You can:

• Add electrical sensors.
• Add thermometers and humidity sensors to the SmartIR climate widget.

That’s almost as good as a bi-directional RF interface.

Complaints and Gotchas

One issue with SmartIR: it uses these weird foreign temperature units instead of Freedom Units (Fahrenheit), even though my Home Assistant is set to Fahrenheit. I haven’t found a way to change that.

If you know how, please leave a comment!

Final Thoughts

This was a fun, educational, and rewarding experience. I now have IR control of my heat pump through Home Assistant.

Next steps:

• Install thermostats in every zone.
• Add temp and humidity sensors to each room.
• Install a heat pump in my new studio space (stay tuned—it's gonna be cool).

If you want to see that—and all the other fun smart home and tech projects I’ve got going on—make sure you’re subscribed.