New bill update £28.49 for the month

£7.14 standing charge was 25% of the bill total

Average unit cost of 6.33p/kw

84% of power was off peak 266kw

My battery is set to recharge to 60% overnight to make sure there is sufficient power for showers in the morning to reheat the tank. This might be slightly too high, but at 5p/kw its really negligible in terms of actual cost.

Posted by: @batalto

New bill update £28.49 for the month

£7.14 standing charge was 25% of the bill total

Average unit cost of 6.33p/kw

84% of power was off peak 266kw

My battery is set to recharge to 60% overnight to make sure there is sufficient power for showers in the morning to reheat the tank. This might be slightly too high, but at 5p/kw its really negligible in terms of actual cost.

You thought your actual total use was circa 1185 in the previous period.

What do you think it was in this period? 

@jeff actual total consumed was 820kw

Power bill for Aug to Sept - £23 - 146kw off peak and 46kw on peak

Big update from my side. Yesterday we had a load of work done at the house.

1) we had the low loss header and the pump removed from the loft. This also means we removed the upstairs zoning, meaning the whole house is now 1 zone. The thermostats are also now gone, bye bye Nest and Salus (if anyone needs one I have them for sale lol). So we are now also running 100% on the Midea controller. I have zero issues from this removal for the moment, the pump seems perfectly happy with it.

2) The filter/strainer has been replaced with a much wider Y-strainer which has helped to increase flow rates

3) My second solar inverter has been installed and my new Seplos battery is in. I've had a few issues with the battery shutting down randomly that I am working through. Not sure if this is a BMS issue, or settings or what. I'm speaking to Seplos so I imagine its just a setting as it comes back to life as soon as I hit reset. I should have it fixed in the next day or so I imagine as I am connected directly into the BMS with my laptop

I'd add some picture, but not really much to add - other than a massive stack of batteries. These changes should hopefully lead to much greater efficiency in the house. I tracked our COP last winter so from the end of this month I will start to track the new COP to see what improvements I get. I would assume some improvement given the removal of the LLH cant make it less efficient. I'm hoping with the controller and LLH removal to get 20+% improvement. This would take me to a COP around 3.6 - 4.0

Awesome, that should see a real benefit in performance. Are you running on just the internal midea pump or do you still have ‘Pump-O’ wired up and running?

@hughf running only off the Midea pump. No other pumps in the system. Seems fine for the moment; if it's running now I can't see why it wouldn't be fine going forward

Posted by: @batalto

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@hughf running only off the Midea pump. No other pumps in the system. Seems fine for the moment; if it's running now I can't see why it wouldn't be fine going forward

Very good, running off the internal pump is the best as then the flow rate can be modulated to vary the dT between flow and return. I'm pretty sure that most modern ASHPs use a PWM controlled pump, I know my Cool Energy (OEMd by SPRSUN) does.

@hughf I'll find out once I start tracking the cop. However I can't see it possibly being worse than on off controls which were previously in place

@batalto - your progress reported here is also very interesting, especially removal of the LLH header and relying on only the pump in the Midea main unit, thanks for telling us. Can I ask how many rads it supplies, and roughly what their combined max (design temp) output is? I still haven't ruled out removing my PHE, and your experience with your system is very helpful in thinking about what to do with mine.

I do think we should bear in mind we have had a mild autumn so far in the south, none of our systems have been put under any significant strain. 

@cathoderay it's a lot of rads - 22. It's a 12kw heat pump. Honestly I can't remember the design temp, I'd have to look it up. However it seems to be ticking over around 1-2kw at the moment and it's fairly cold outside

Our house is suddenly a lot warmer - at least upstairs is. My wife even remarked on how warm the rads are. Clearly I need to adjust downwards!