Daikin Altherma, ESPAltherma & Home Assistant with OpenEnergyMonitor

I used this cable but put 2 together to get 1m. Just strip off 8 cables from the full strip. https://amzn.eu/d/hDo11L7

This was enough to put a box behind the HP and the cable reach the inside. I used this to cover the cables from the box to the HP: https://uk.rs-online.com/web/p/cable-sleeves/1874616?searchId=55bdf9cb-6aaa-41a1-a8e4-764a5d39f78c&gb=s

The M5Stick, Ip68 enclosure and gland are all available from RS as well. All in stock now including the M5Stick (which despite the picture ships the latest model)

Hi all,
Does anyone know of CT clamp that is battery powered and obviously linkable to HA? Thanks!

The Harvi powers itself from the CT itself, but I’ve not seen any other implementations that do that

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Another 9kW Altherma Octopus customer here, suspecting that the heat survey was Very Pessimistic and that our heat pump is…much larger than required. I’ve added a esp32altherma and installed a Emporia Vue2 whole home electricity monitoring system to look more closely at what’s going on.

A question for those that have already done this: where is the best location for signal strength inside the heat pump case? Even though I’m using a esp32 with an external antenna, I’m still only getting -88dBm to -95dBm signal strength, which isn’t great. I appreciate it’s sitting inside what amounts to a faraday cage…

I’m not going to modify the Altherma case in any way, so is there a location inside it that WiFi signals can more easily get in & out?

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Hi Jonathon,
Welcome to the Daikin support / therapy group :wink:

Sorry, I’m not going to really answer your question but I figured it was better to get the ESP32 outside of the Althetma case, so I used some CAT5 to extend the DuPont cables and then fed the cable through one of the holes in the bottom of the unit.

The ESP32 is inside an external weatherproof box, which also contains my WiFi extender. Not the prettiest solution, but has been pretty reliable for 3 months now.

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Cheers nearly fellow Jonatha/on. :grin:

“…fed the cable through one of the holes in the bottom of the unit…”.

That might be my answer, except that I would look to get a (shielded if possible) aerial extension, so the esp32 could stay nicely protected inside while only the external antenna came out of the bottom of the air source unit and onto the top. #SilverDuctTapeForTheWin

I didn’t see any holes on the bottom of the Altherma case. Could I please have a hint where to look? (Thinking phone videoing & passing it around underneath to locate it).

Another possible option would be to run a cat5e cable up to the consumer unit and put the m5stickc in there (inside a small project box).

If I’m understanding you correctly, that would involve drilling a hole through my external wall and running ethernet cabling through the house. Not going to happen in the short term. (Building a cat6a network is part of a future home renovation plan).

So for now I’ve ordered a double shielded 5m SMA Extension cable. https://amzn.eu/d/1g6rpt1 Yes, it’s longer than I need, but gives flexibility (and I couldn’t find anything shorter suitable priced ). I’ll play “hunt-the-opening-in-the-bottom-of-tye-case” when it arrives.

Separately, I’m a little… suprised at the lack of insulation on the large copper pipes in the Altherma 9kW. There’s a few bits of insulation here and there, but the lack of insulation on metal pipes in a metal box can’t be good for efficiency. It’s basically seems to be heating the great outdoors at our expense. :⁠-⁠\ Odd, given the careful attention paid to insulation in modern building techniques.

If you have an octopus install theory put a waterproof consumer unit in the wall next to the heat pump.

This has room to fit the module in and as a bonus it should have some conduit with enough space for a single cable already installed.

@EnergyExplorer You won’t hunt for long - the cover has space behind it, and around the frame to the left of the front opening. My cable just runs down from the X10A socket, towards the left, across the PCBs and out through the space, then loops back under the HP case towards the back and across to the box on the wall that holds my M5Stick. Not sure where you plan to put the external antenna, but it would work well on the top of the case to increase its effective power.

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A photo might explain my thinking. I’m using 60CM Female to Female Dupont Cables to connect the ESP32-WROOM-32U to the Altherma motherboard. There’s a variety of locations it can be tucked into, though none of them give very good WiFi signal quality. Now I know theres holes under the case, it’s simpler (and probably gives less signal interference) to use a £9.99 double shielded SMA extension cable to pop out the bottom and up the side of the case.

This will come up 1.5m closer to a house window with line-of-sight to a WiFi mesh-router. We can’t see the heat pump unless we get close to the window, but it should be more than good enough for the 2.4Ghz signal.

I’m thinking of using silver duct tape to hold the cable & antenna up along the side of the Altherma, poking it 13cm above the top for minimal optimal reception (as 2.4Ghz wavelength is 12.5cm).

Here’s a photo taken of rhe underside from the front, between the two feet on the right hand side:

And a closer view:

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We’ve had good success with the ShellyEM, but have recently been testing the Tuya Zigbee for places where wifi is problematic and found it to be very good for the price point. Below is a graph of the hour consumption vs reliable smart meter CAD - the Tuya over-reports consistently, by 2.1% on average but has shown up to 7%.


Success! The signal strength went from between -85dbm & -95dbm (barely useable), to between -55dbm to -59dbm. At it’s best that’s 40dbm better, I e. 10,000x improvement in signal strength (as dBm is a logarithmic scale).

A few photos. Here’s the new location for the ESPAltherma, sitting on the floor of the Daikin heat pumpm. The double shielded antenna extension cable goes of of the case via a convenient gap in the case.

Photo is underneath the heat pump, looking up at the gap where the cable comes out. Lots of room for it., IE cable is not pinched.

Pic of end of extension cable plugged into the antenna. I then wrapped the connection & articulated section in electrical tape to keep water out.

Final home for the aerial/antenna.

After doing some testing I found I got a very respectable -55dbm by placing the antenna at the top inside the corner protector piece. Yes I got a bit more signal by placing the antenna on the outside on the heat pump case, sticking up above the top. However, I preferred the discreet, protected location hidden in the corner piece. Silver duct tape keeps it nicely in place, with spare cable loops tucked under the heat pump case. (The cable was much longer than I needed, but the price & performance are excellent).

I’ve had no dropouts since setting up the antenna. Very happy with the install. Low cost outlay, no soldering required, frequent metrics to Hone Assistant. Recommended!

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I like this setup. Nice and tidy. Any chance you have a parts list?

I’m now torn between placing it within the Octopus consumer unit and your solution.

Do you have an Octopus install, if so, was there a reason you opted for this rather than putting the ESP32 inside the consumer unit Octopus installed?

Another month until my install so I have some time to decide :slight_smile:

Given Jonathon has resolved his signal strength issue, this is aimed at others who may be experiencing a similar issue, but have yet to purchase the coaxial cable.

At Wi-Fi frequencies (2.4 GHz) coaxial cable is quite lossy.

To keep losses to a minimum, use the shortest length of cable that’ll get the job done.
Use quality cable. Avoid cable types such as RG-58, RG-59 and especially the smaller
types like RG-174. (174 is very lossy at 2.4 GHz)

RG-6 or RG-11 would be a better choice.