I found that Homely blog a few days ago and was tempted to do a demolition job, but then decided against it at the time. The methodology is somewhat opaque (a search on the Energy House Labs facility at Salford University website found nothing) and there is definitely some whatiffery (aka modelling) in play eg to make the results 'more relevant to other homes in the UK' which just bumps up the amounts and makes the absolute value of the savings appear larger by using an 'Assumed mean space heating of 11,808 kWh', which rather on the high side. The 'can save £444 / year' comes from comparing Hotly Homely with, by Homely's own admission, the worst case scenario, fixed flow temp with Time of Use (ToU) tariff. On the more realistic comparison to a system running weather compensation on a non-ToU tariff (which is what I have, as do many others), the saving is a more modest £158 on the souped up 'more relevant to other homes in the UK' numbers. The actual test results only achieved a £85 saving, rather far cry from £444.

The blog, posted on 10th May 2024, notes that 'We will be sharing more on these results in future updates'. I can't seem to find any further updates by searching the Homely website... 

More generally, we are up against our old enemies, comparing like with like, and efficacy vs efficiency (lab results vs real world experience). Determining what the ordinary heat pump owner might realistically save is far from easy. There might be some savings, but I have to agree with the Major's view that a well set up system running weather compensation at as low flow temps as possible is going to get pretty close to maximum efficiency and savings, meaning there simply isn't that much more to be saved. Any suggestion that there is has to be taken with. to put it politely, a large pinch of salt. That said, there may be other benefits from using Homely that individual owners might wish to make use of, if that works for them.       

Posted by: @majordennisbloodnok

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most people we see on the forum now are recognising they can insist on a system installed with weather compensation and choose to run just like that without any thermostats at all. That fourth option is the preferred for quite a lot of forum members and the posted stats/bills for many of these installs show very good running costs already.

A bit slow on the uptake commenting on this, but I found this really interesting and to be honest didn't know, or at least didn't consider it, as an option.

For whatever reason our homely stopped working correctly yesterday again- HW tank temp just stuck at 21. A reset sorted it, but clearly a bit of an ongoing problem.

I don't believe that our ASHP is wifi enabled unless I install the associated Clivet HID-TConnect2 i.e. their smart thermostat. What I can do, and Clivet/Midea make very easy in fairness, is connect something to the modbus as there is a modbus connection within the indoor control panel. This is what the Homely is connected to.

I can easily swap this over to something like the Planet Atmo which then (from what I can tell) allows me to control all of the parameters via their dashboard and I can then configure the app with the controls that I want to use in that. I thought the blocker to this was the lack of indoor thermostat/temp sensor and the functionality that homely provides in this regard with the node.

From what you say, What I could do is simply set the appropriate weather curve to get the indoor temp just right...

This would also resolve the slight oddities that our homely does exhibit on occasion by running what appears to be flow temps that are unnecessarily high, causing the IAT to overshoot. We've never had the Smart + option enabled so there's never been any reason for it to do this.

The other option I have is home assistant. I do in fact have home assistant already with precisely one automation thus far- to tell me when my tumble drier has finished, using a smart plug! That said, if I am understanding it correctly I will need the wifi enabled Clivet controls.

That, @benson, is a question with quite a few facets.

Firstly, yes you can set your heat pump with the desired weather curve to give the home temperature you want and then leave it at that. That’s precisely what a compensstion curve is for. It takes a bit of fine tuning to get spot on but is generally very stable  once done; Homely, Havenwise, Home Assistant, Planet Atmo, none of them are necessary per se.

Of course, doing that won’t give you any stats or other visibility of your heat pump’s operation (although nor will Homely to be fair), and if you ever want to tweak beyond the WC curve then you’re back to the console or the manufacturer’s app (which will need a wifi module).

That said, you mentioned Home Assistant and modbus in the same post. Whilst HA can connect to cloud systems it can also connect via modbus to whatever you wire in; that’s precisely how I’m interacting with my inverter for my solar PV and battery control.

I would also say, though, that whilst I could connect to my heat pump locally via HA, I prefer to let it run as installed. Purely based on my preferences, in your situation I’d connect HA via modbus purely for the informational stats, configure the heat pump’s WC curve as you described earlier and then leave it alone to do its thing.

@majordennisbloodnok thanks. I am probably going to give the planet device a go then, as either way I’ll need a WiFi enabled controller of some description connected to the modbus…? Or rather should I say I don’t necessarily need anything connected as you say, but I would really need this wireless/remote access and control for example to boost HW without having to go into the control panel manually every time.

It will also provide an interesting comparison of running costs versus homely.

Posted by: @benson

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…either way I’ll need a WiFi enabled controller of some description connected to the modbus…?

Not necessarily. A cable attached to the modbus ports at the HP end and plugged into your HA box’s USB port could do it. Alternatively, an RS485 to Ethernet converter could do. So could a little ESP microcontroller plugged into the modbus ports. Point is that there are options. A wireless controller could be good but it’s not the only choice.

Probably best to slow down a wee bit and we can all help understand what you’re trying to achieve and work a plan of action.

At this point, @cathoderay may well be a useful person to bring in here since he has written quite extensively about talking modbus with a Midea heat pump. The Planet Atmo is, unless I am much mistaken, around £120 so it's worth waiting for a few alternatives before putting your hand in your wallet.

@majordennisbloodnok thanks. The reason Planet appealed was because they seem to offer a dashboard much like Homely, and an app so I would have a hopefully user friendly interface to appease the wife to operate key parameters such as HW boost (that is the main one we use from time to time). It seems as though it offers all of this, I could set it all up with a simple weather comp curve and see how it compares to Homely. If we can achieve similar results in terms of cost and efficiency, and move away from the model of our heat pump parameters being controlled by a third party, I'd consider that a win. 

Planet have provided a list of parameters/settings that can be both monitored and controlled which looks really decent, but I have a lot more Qs before pulling the trigger. Not least I can't find their app anywhere in the appstore, or a demonstration video of it. They also mentioned that they are releasing a pro version which will have an external temp sensor.

@benson - I fear it is going to be either Homely or HA or other python over modbus, because there can only be one boss on modbus. If you do decide to go down the HA or HB (home brew python) route, the connection is straightforward, see my thread on the subject here. The only bit missing is my custom python code, never got round to posting that - maybe this will be the stimulus I need!

@cathoderay thanks. Interesting stuff. As said I do have HA (the pre built HA green in fact). I think it just boils down to being able to use an app for one or two features we need which we can toggle on and off with ease, which homely does provide.

I have had a read of that thread (which is brilliant btw) and it does certainly all look doable if it was just the monitoring that I needed.

@benson, I know I sent you an IM but on reflection it may be useful to others as well.

This document...

...from a Clivet distributor strongly suggests the heat pumps usually ship wireless-enabled anyway. I've heard that the setup process may not be as user-friendly as it ought to be but it's an avenue to explore since if you can shake the already provided functionality into life then you have at your disposal the controls the manufacturer intended for you anyway, and at no extra cost than a bit of time and head-scratching.

@majordennisbloodnok Thanks for above. I have given it a go this afternoon.

If I search for devices it doesn't pick anything up. I have found a QR code on top of the indoor control panel but this doesn't seem to be doing the trick either unfortunately.

@benson I have gone down the Home Assistant and waveshare modbus to ethernet adapter route for my Grant Aerona3, I have posted an integration on github but I am still working on it so not entirely ready for broadcast just yet. I did post my original project but I have also gone down the custom python route and am developing a complete integration it currently has 284 entities exposed, so I am trimming it down to the most useful. Then I will look at integrating all the external sensors people may have like room stats, weather stations etc to predict and then learn from settings changes.