DamonHD

FYI: https://wind-curtailment-app-ahq7fucdyq-lz.a.run.app/

But I cannot run the heat pump at all with the dregs of PV low generation in as agile way as with diversion. (I don't mind spilling to grid because it gets used to avoid gas burn usually at the moment.) I also avoid diversion when grid demand or carbon intensity is high, or frequency drops to which I respond within a minute. None of that agility is easy with minimum hp compressor cycles lengths and minimum power draw. Starting from fresh I and given that I *do* now have a heat-pump I might use a bigger electrical battery instead.

Yes, I believe it does even now, eg the Thermino loses heat at half the speed of the DHW cylinder even when much hotter, and at a rate comparable to the electrical batteries' self-discharge. I had the Thermino+Intasol long before I installed the ASHP. Given the rapidly falling price of electric batteries now cf when I started it would now make sense to consider additional electric battery (in particular to be able to cover the maximum power demand of the heat pump) instead of heat battery for new installations.

Not true for me. Via tight control using my Eddi, I regulate how full I let my Thermino get and choose whether to let it get full enough for its automatc cut-out to operate or not, which enables me to do things like this to reduce our grid exports around solar noon to be kinder to the grid: Full-week 15-minute con consumption and net imports for 2025-07 generated with sh script/storesim/load_profile.sh 202507. Full-week gross consumption and net grid flows for 2025-07. Times UTC. Data and other views are available. And there is about 30% heat capacity above the 58C point before that cut-out.

I'm heating by diversion so that doesn't apply.

I 'fill' my Thermino to ~80C which adds ~30% to the nominal capacity over the phase-change temperature.

Here was the set of talks (PDFs with some earlier audio/podcast versions)... https://www.earth.org.uk/Kingston-Efficient-Homes-Show-2025-Bitesize.html#Short

If we are going to electrify everything to achieve Net Zero then the DNO is going to have to deal with much bigger power demands in both directions eg from PV generation and EV charging. Upgrades will need to happen. I think that the DNOs accept so. It is not your problem to make that happen.

It is the DNO's legal responsibility to keep RMS voltage within bounds, as I understand it. My dad's PV used to shut down occasionally from overvoltages, being on a semi-rural weakish feeder. I believe that it got fixed.

FYI: https://www.earth.org.uk/note-on-16WW-mains-voltage-monitoring.html I regard anything below 235.5V here as a sag, and stop diverting PV to my heat battery within 60s if so... Rgds Damon

For the record our Thermino is doing just fine, helping us soak up solar PV in the middle of the day in particular and reducing how much DHW we need from the heat pump. https://www.earth.org.uk/note-on-solar-DHW-for-16WW-UniQ-and-PV-diversion.html An alternative these days is to have (more) electric/mains battery along with the heat pump to act as a store.

There is another 'bitesize' event in September: https://www.eventbrite.co.uk/e/bitesize-efficient-homes-show-tickets-1492300303379

To confirm: lots of research in the UK in the field (eg Energy Saving Trust, Energy Systems Catapult, others) has shown that there is simply no type or age of dwelling that can't have a successful retrofit, though some awkward cases will be awkward. And indeed making the retrofit by 2050 of ~20M UK gas boilers with (mainly) heat pumps work well is the topic of my research. FWIW I only replaced one rad when I upgraded to a heat pump at the end of last year.

My newish heat pump is working fine. Being short of hot water sounds like a tank sizing problem not a heat pump problem. It's bad for the planet to install a new fossil boiler.

Not great for tourism was the Paris-sized wildfire that burnt ~80km away from us towards Spain, due to climate-change induced drought and heat. Last week, not some mythical ignorable distant thing. The firefighting planes were sometimes flying over us.

Not quite! Peaks are actually: DHW top-up by heat pump, DHW top-up from PV, evening meal being cooked, DHW top-up by heat-pump! Please admire the chunk of exports that I've managed to notch out, ie avoid spilling to a busy grid, at noon! FWIW, my laptop is using ~4W.

From conversations I had recently I think that you could get that spec at *wholesale* prices, but no install nor retail margin. But bulk battery costs are falling very fast at the moment.

Well, in case it helps anyone else knock ~16% (!) off their standing load in two shakes of a lamb's tail like that... Times are UTC. More data/graphs: https://www.earth.org.uk/img/PV/load-profile/202506/

Mine is more like 150W overnight including all the batteries / diverters / heat pump / monitoring. The battery reduces that to ~10W from the grid.

Seems possibly to have been a manufacturing fault, and the units shipped to you were not fit for use for a reasonable lifespan. You may be due at least partial refund? Our triple glazing was a bit explody - I think because it was a new manufacturing line - and we had no arguments at all getting things fixed under our warranty. https://www.earth.org.uk/triple-glazing-3G.html#Failures

I deny everything.

This ought to be a poCcast, to rival Joe Rogan...

Well, get one that is water- and energy- efficient, that she likes, I suggest. Cold only is fine.

Both circulating hot and washing unnecessarily at 40C or above are huge consumers of energy. (And washing too hot ages clothes prematurely.) That costs money and climate emissions. The OP was talking about 'savings' from a dual-fill machine. Better savings would come from NOT having circulating hot and NOT washing hotter than actually needed.

One huge energy saving (~80%) is to run washes as you can cold, so buy a machine that can do that. We do everything except bedding on cold. https://www.earth.org.uk/note-on-Zanussi-ZWF01483W-freestanding-washing-machine-REVIEW.html Also as @JohnMo says, a water- (and thus energy-) efficient machine may not draw enough hot for it to reach the machine at all from the tank/boiler.