Hi, sorry I have not followed this topic, but just dipped in and may have misunderstood, but I saw 45000 kWh annual heating usage? Our heating and DHW used 5800 kWh Oct23-Oct24. We have UFH in concrete floors throughout and only heat about half the 3000 sq ft house, with a 11.2kW Ecodan sized for the whole house. It says it delivered around 20000 kWh of heat so a CoP of around 3.5. We run the kitchen/living room at 20C at 700am - 21C at 1300pm, off between 1600-1900, 20C from 2400 (and it pauses unless the outside is very cold) - 21C at 4.00am. This is to use half price electricity on Octopus Cosy, so our CoP won't be optimal but our costs are lower. I use the Advanced Auto Adaptation with the wireless stat in the kitchen/living room. I previously used Weather Compensation mode but find the AAA very good with almost no cycling, of which I am rather paranoid. When it's not really cold I switch to Quiet mode which limits the Flow Temperature to around 45C on medium, or 40C on low. One thing I would recommend is getting a Smart Meter and on ours I can set a red light to come on at say 500W which tells me the HP is heating and has enabled me to balance our system to minimise cycling which would reduce efficiency, slow the heating and I believe cause the Heat Pump to wear out prematurely.

Posted by: @sliderule

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One thing I would recommend is getting a Smart Meter and on ours I can set a red light to come on at say 500W which tells me the HP is heating

Hi @sliderule -  can you elaborate on that please?

These are the component parts of a Smart Meter system:

Are you referring to the In Home Device (IHD)?

Getting a red light to come on at a particular power level isn't a feature in the SMETS2 Specification.
So can we assume this is an 'extra' which is available on your particular IHD?

Which one have you got?

I refer to the Smart Meter In Home Display. We have the old model, which has a red/green usage light that you can adjust in the settings to turn from green to red when the usage exceeds say 500W, which is a quick way most of the time to see when your heat pump is actually heating. I haven't seen the later model Smart Meters but assumed they can show the same. I know you can also see all this on MELcloud now as well but you have to keep refreshing it.

I agree with Econonsense that adjusting the Weather Compensation is not best done by installers as they can't be there over all the differing weather conditions to achieve the optimum settings, and will probably set it too high to avoid complaints of inadequate heating, which results in high bills. But there is the alternative of Mitsubishi Advanced Auto Adaptation, which does it all for you. It probably aims slightly more towards comfort than economy, but I am very happy on both fronts. It requires a Mitsubishi wireless thermostat which you clip on to a wall mount, and a receiver which is connected into the FTC (Flow Temperature Control) box which is usually found on the Hot Water Cylinder. The wireless thermostat is portable and can be moved into say, a lounge, but should normally be in the room where the most consistent heat level is required ie the living room, next to the original thermostat which should be set 1C higher to ensure the zone pump runs at the same time as the heat pump. It also has holiday and hot water selections. Any target temperatures that are programmed into the FTC, eg night set-back, automatically appear on the wireless thermostat. It does require a dip switch change in the FTC which is easy enough (always photograph the original settings first!), but most people would need their installer to do it (assuming he is knowledgeable on the Advanced Auto Adaptation system, which is relatively new). In my opinion this transforms Heat Pump setting-up and could avoid many complaints of insufficient heat or high running costs. I have heard it said that it works better for radiator systems, but it works perfectly on our UFH system.

Posted by: @sliderule

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I agree with Econonsense that adjusting the Weather Compensation is not best done by installers

I think you will find you were agreeing with me, it was I who said there was a case for occupiers rather than installers doing it!

I'm interested to know what the Mitsubishi Advanced Auto Adaptation takes into account, and how it does it. I found this description, which suggests it uses the difference between the actual and desired (target) room temp, which is what I do using a python script on a Midea heat pump using the current (and therefore real) difference, but the Mitsubishi implementation some does it for future differences. Does it have a crystal ball inside? The diagram, such as it means anything, suggests it tracks recent differences, and then projects them into the future. But that assumes nothing else changes... 

I do note however that you say the system 'just works'. But it would be interesting to know how it works. 

This thread is heading in two different directions; and @editor  may wish to split out the information on Mitsubishi Advanced Auto Adaptation to a different/new topic.

@sliderule you are quite right to post here about this, even tho' it's clearly unrelated to thermal losses in the DHW supply at @econonsense 's site.

When you next respond, could you please two steps back and start with an overview of what issue you think the AAA feature is intended to solve?
... then tell us why you're mentioning a zone pump - preferably with a diagram if Mitsubishi have one you can paste here

... and then describe that DIP switch in the Flow Temperature Control box (photo?)
what it's for
and why it needs moving.

Links to online references on Mitsubishi's own site would be even more welcome 🤗 

That will leave this topic to remain on-target to address the heat losses and excessive costs for @econonsense

Many thanks.

I absolutely agree with you regarding installers and Weather Compensation. Because of a house wiring problem where we couldn't connect the zone controls to the FTC, I tried out Advanced Auto Adaptation using the small FTC panel (which has a built in thermostat) on a long lead into the living room, as it didn't t need any zone signals. It worked fine, so I bought and installed the Mitsubishi wireless thermostat and receiver. It pauses or shuts down the HP when we get a temperature rise eg heat from the sun. I don't know how it works only that it measures the inside and outside temperatures and is supposed to learn over some days the appropriate adjustment to the Flow Temperature according to the performance in the house. Out of instinct, I only program in 1C changes in target room temperature, to avoid too fast ramp-up. On other topics on this forum, people have discussed how it works but I don't think they reached a conclusion. Several people thought they could beat it's performance using WC. I am very happy with our performance and I have a personal aversion to HP cycling which I believe reduces efficiency, slows down heating and wears out the heat pump prematurely, and I have noticed much less cycling with AAA than WC, almost none in fact.

@transparent Thank you, that may take me some time to do that. I suggested AAA as an easier way than WC to get reasonable running costs. Most people would need their installer to fit it but once fitted there should be nothing to do.

In an attempt to clarify this - isn't AAA (Advanced Auto Adaption) an addition to more basic weather compensation. It still varies the flow rate based on OAT, but does it taking other factors into account as well; it isn't therefore a case of AAA or WC, rather of WC (basic) or WC + AAA? Or does it entirely ditch using the OAT in any part of its logic. Very happy for thread to be split as indicated. 

@cathoderay I am sure AAA measures the OAT as well as the Room Temperature, to adjust the Flow Temperature. In that way AAA differs from WC which does not take into account the Room Temperature except on a stop/start basis. Also AAA does not follow a preset curve like WC. Presumably the "learning" is something to do with the observed rate of change of Room Temperature, but that's just guesswork on my part. Others have said it takes days to settle down after a restart to the system. The advantage of AAA is that no trial and error of the WC settings are needed for different weather conditions/seasons, which may have to change again if HP cycling occurs. That may not concern HP enthusiasts, but should be a big advantage for the general public.

@sliderule - thanks. I suspect even heat pump enthusiasts would welcome anything that reduces the tedium of tweaking and fine tuning weather compensation curves, an activity which has much in common with watching the paint dry.

I do already have a basic auto-adaption setup, a python script that checks the difference, if any, between the actual room temp and desired room temp, and then, if there is a difference, it adjusts the flow temp by moving the ends of the weather compensation curve accordingly. Generally it does work eg if I run with an overnight setback, and the actual room temp drops by a few degrees, then the auto-adaption script adapts the weather compensation curve to achieve a post setback recovery boost, and removes it when the room temp is close to where it should be. The code isn't complex, it is a series of 'if this then do that' statements. I am now turning my thoughts to what other auto-adaptions I can include, hence my interest in what other auto-adaption systems do. The two obvious candidates are firstly the weather and secondly the buildings thermal characteristics.

The weather of course is unpredictable in the detail, and I know from other work that I have done that converting weather data (actual or forecast) into something a computer can use is far from easy. Take solar gain for example. It would need something like the predicted (or actual) number of hours of sunshine to be useful eg if predicted number of sun hours > 5 then lower the weather comp curve a bit. Ditto for rain but wind is always harder to quantify eg how do you turn cyclonic then SW veering NW 5-6 decreasing 4 later into something a computer can use? Calibrating the building's thermal characteristics might not in fact be that hard, and probably only needs to be done once (unless you have the builders in). Most if not all of the key data is already available, energy delivered to the building, rate of change of indoor and outdoor temperature etc. Without even doing any sums, I know that my building is slow to heat up, but equally it is slow to cool down.  

That said, most of the time my weather compensation plus auto-adaption script works just fine, the building stays at a constant indoor air temp, unless I have an overnight setback, when there is an overnight dip, but of course that is meant to happen. What matters then is managing the recovery boost, which is done by my auto-adaption script. The times when my indoor air temp does fail to stay where it should are almost always in severe cold weather, and the failure isn't down to a failure of control, it is down to a failure in heat pump output (see the Bleak Midwinter thread for details). It may be that the system I already have is already 'good enough' and any further tweaking will move into the realm of diminishing returns.

I do realise that not everyone will want to do the sort of tweaking I do, but at least I have established it is do-able, for those who want to give it a try. I also realise I haven't solved the getting the weather curve/control logic right with minimal effort problem, I still had to tweak mine over weeks if not months to get it right, and I still find myself adjusting it by very small amounts every now and then!