Wil

For DHW- It’s a lot simpler to divert PV into an immersion and deal with the loss of efficiency than trying to match the ASHP input to it. You’ll also be able to sink a lot more heat into the tank with an immersion compared to an ASHP. Ideally I suppose you’d ASHP to 45degrees then immersion everything else for efficiency. If the sun goes behind a cloud while using the ASHP, then you’re paying for the kWh it consumes whilst the suns hidden (or on a cloudy day). If your PV is at 1kW and your consumption at 250W, then you can put just the 750W extra into the tank. Depends if you care about zero grid consumption or self-utilisation of the PV.

Hmm bad luck. I’d been on E7 for the previous 3 years though and it has the same effect, just not as good rates as the intelligent go. If you can load shift to your 7 hours at least it’s 16p as opposed to 34 or whatever your peak is. We also found in the summer, the tail of the E7 period would cover our morning routine and showers/ shoving the kids out the door by 8. (Ours was a dumb meter and was 12-7in DST and 1-8am in BST).

No external antenna that can be fitted to help it read? That was potentially an issue for us too, but harder getting a 3phase smart meter installed and then a suck-it-and-see if it works… jury still out but they let me switch…

These shoulder seasons are great when the sun shines for the PV. Less so the rest of the time. In November, I moved to Octopus Intelligent Go (pre-requisite compatible EV). Which gives 7.5p from 11.30pm to 5.30am, 29.5p the rest of the time. We absolutely rinse the 23.30 to 02.30 slot- Tesla batteries (20kWh) and car take around 40kWh between them if the car has been out and about. Actually do night time set forward on the ASHPs to run during cheap (20degC target temp). Then set back at 5.30 (19degC). We load the dishwasher through the day and set it off over night. The same with the washing machine. Timed boost of the immersion from 04.30 to 05.30 to make sure the 300ltr tank is at around 56degrees which means we’ll get through to the evening on a normal days use. We usually wake up to about 56kWh overnight usage, then if I can get 10kWh out of the solar I can go the whole day with no peak grid use and the occasional heat pump blip to keep the temp up. The wind turbine appears to save about 10p per annum. It’s not in an ideal spot tbf. Octopus appear to have balls’d up my billing (despite the smart meter) and apparently I only owe them £18 for December and January… considering the standing charge is around £14 a month I fear I’ve got a shock coming… either way, it’s way better than my previous Octopus flex economy 7 which was 16/34p and 45p standing. Oh and the saver sessions are great too- just turn the HPs off and let the battery reserve take the slack for £8ish saving. Thank you.

I have 5kWp of panels connected to a 3.68kWp inverter. All self installed. Means a bit of clipping at max output but it starts generating slighting earlier and hasn’t been any issues so far. Hopefully the panel degredation will never be an issue as it was oversized to begin with. Lack of MCS currently means no payment for export, but that may be able to be changed. Try and size to self-consume. Hybrid batteries inverters charge the batteries direct from DC and allow for G98 install. AC batteries mean g99 regs as both the solar inverter and the battery inverter need to be summed as they could both be outputting at the same time.

How strange. I dread the day my dream machine packs up- we rely on it for so much of our lives. Regular backups are vital as even minor config changes can be a total PITA to undo if it all goes to hell. Don’t know if you could insist on an upgrade, but definitely on having a new one from European stock ahead of RMAing your existing.

Octopus Intelligent Go gives 7.5p from 23.30- 05.30 @Originaltwist are you the author of this website? https://originaltwist.com/2018/11/14/diy-fan-coil-heater/

AIUI the log burner is treated like any other plug in single room heater (as in it’s ignored for RHI) unless it contributes to the central heating. I wrote a long post to say £300 a month is not unheard of in the depths of winter depending on the amount of heating she’s using. It is a bit of a worry in a newly renovated property, so definitely sounds like it could do with some help setting up or user education on running it. For reference my leaky 300m2 5 bed used 1.02MWh(e) for heating and DHW in December (plus the log burner pretty much every night in the living room). At a cost of £302 apparently. Comparing to July when we used 81kWh(e) for DHW for £19.85 apparently (not including for solar DHW). I need to have a better look at my totals for annual, but I’d reckon around the 2k mark for heating and DHW across the year. £1500 a month or even £300 a month across the year is completely unrealistic in your neighbour’s case for a renovated 3bed.

Phil is correct, I’m on the RHI and have both standalone woodburners and solar panels. No relevance of either to the RHI. Mine were there before the HPs, and were mentioned in the heat calcs for the MCS cert.

But what is your winner? Or is it just me that can’t see it?

Could I put one of those units in a fireplace and reject the cool/ heat up the chimney? I have multiple 200mm holes in my roof which are currently blocked at the room I could use… And are they too noisy for a bedroom?

Either you put it on until it trips out on it's in-built overheat stat (this can usually be adjusted). At this point you know your tank is as hot as you can have it. Or you boost for a period of time to suit usage. This will only come from experience but a 3kW immersion in my 300ltr tank is a decent boost if on for an hour.

You may want the immersion as backup or to dump any solar you may have? No need to switch it right off if the legionella cycle has been disables as it just won't get used unless it's wanted.

Are there any recommendations for an inline that will get a shower going but drop off as the hot water reaches it from the forum hive mind?

It uses the same wiring as the existing Solic. There’s a fixed load (3kW immersion) on the end and the same 16A breaker at the beginning of the circuit. Then a solic and a Shelly in parallel. Effectively two switches between the same load and supply. If they’re both on at the same time, it’s no issue as both fed from the same place and protected by the same breaker. If the Shelly is on the whole 3kW boost is active for as long as you programme the Shelly. If the Solic is on then it trickles whatever is left. I left the solic in all the time and just used the Shelly as a timed (or remote manual) boost. If you did have a different feed to each and on to the immersion, you’d have to be more careful about paralleling.

I went even simpler than this and wired the Shelly in parallel to the water heater instead of messing about with the wiring. Same 16A feed to both, same output to immersion. Then set a schedule on the Shelly for 1hr at 5am (or whenever you want to schedule). This way I could switch the immersion on whenever I wanted and leave the Solic standard and free to feed the excess whenever the PV was out. Separate Shelly 1 with add on temp probes to give me tank temp but I never linked the two operations as an hour of 3kW immersion was plenty for my tank. Edit: Since getting batteries, I removed the solic altogether and just switch the immersion on when the batteries hit 95% and the PV is over 500W (to ensure the immersion isn’t on at night when the batteries charge off cheap rate) and turn it off when the batteries go below 88%. Rinse and repeat as the batteries fill back up with solar.

Apologies, I meant replace the unit which failed due to a known defect with another… Way too much to expect them to fix it…

I have a nest which has decided to give up connecting to wifi. Works wonders as a pretty ‘dumb’ thermostat though. Google refuse to fix it as it’s old. Now my nest hub has started playing silly buggers with wifi. It’s almost as if they design in failure after 3 years…

That’s just a shortcut to ‘resilience’ isn’t it? 🫣

Sorry to hijack, but vaguely related: I was having a chat with a friend about to do a major ‘back to brick’ returb of an old Manor House in the Peaks. They mentioned that their/ the builder’s interpretation regs covered zero rating ‘energy saving materials’ so including all their insulation and solar and heat pump and batteries were covered and were able to be zero rated. Has anyone else managed to zero rate all their insulation, batteries etc?

Looks like you’re well covered, of course in a drain back system the pump needs to run that way around! Hope the experiments work out better for you with your alterations!

Forgive my questions, but: 1. Doesn’t the ST panel flow in at the bottom and out at the top? 2. If you put a Three port diverter on the return from the heating/ DHW to the ASHP, you could save the energy of the primary side PHX pump and let the ASHP pump do the work moving water through the PHX. * When your PHX temp is higher than the ASHP return temp* Rough scribble:

Love the tinkering. Can you post a rough schematic of how you’ve put this inline with the ASHP. I’m struggling to see what you’re doing unless literally running the ASHP return through the secondary of the solar PHX?

I have 3P and am on Octopus but they can’t/ won’t offer me a 3P smart meter so I can’t change to any of the more appropriate tariffs. 😞 Each time they give me a meter install date, I ask if they’ve clocked it’s 3P and they say no and drop it. I’ve tried 3 times now.

So we have/ inherited a pond with a stream running into it, I’ve been clearing desperately and it turns out that at some point it’s been used as a well for the farmhouse. The old lead piping is still there in places. Half our roof also diverts through the pond. But the stream is dry in summer and runs fairly well in winter. Realistically any heating would be absolutely negligible given the flowing nature and at the moment it just clogs up with Algae and sediment running off the farmer’s fields. Considering the chemicals they’re using probably run through it too, it just seems like it’ll have to be ornamental. Gratuitous digger pic. I definitely wasn’t stuck at this point. Definitely.