Is the BUH used during defrost cycles, had 7kw pulling yesterday morning at 7am.

@gary hello again Gary. Now running heat pump at 32c and finding that the 3rd party room stats are now switching off the ecodan at 22c. Is that any different to the cycling that occurs when the heat pump is controlling the flow temp? 
Outside temp is warmer today +4 instead of -3

Before you were cycling every 20 mins has thst now stopped at 32C.  If the temp doesnt drop so that the thermostat turns it back on in 20 mins then it will be cycling less.  You could try 30C and check if the cycling comes back.  It’s unlikely you will ever find the perfect setting.  Mine is running at 32C has been since 12pm and the temp has changed from 21C to 22C but in the time the heat pump hasn’t cycled once. Here is an hour from this afternoon

Well, that was an expensive weekend, certainly.  OAT varied between 0 and -9°C over Sat/Sun, with heating (exc. DHW) consumption of 52.8 and 54.4 kWh respectively.

Made for some nice outlier points on my charts though...

(NB:  all CoP figures are Vaillant's self-reported figures, as I don't have any better monitoring at present.)

Looking forward to trying out Octopus Cosy (which I've calculated ought to help with the cost a reasonable amount), and all the more to our battery and solar installation in due course (hurry up, SSE!).

@josephiah We are using Cosy; the overnight 12 hours before the next 3 hour cheap rate is the greater challenge though. We have 27 kW/h of storage battery (2 x Powerwall 2’s) and I am trying not to draw from the grid outside of these 6 hours per day. We came rather close to having to use a little grid power between about 02:00 and 04:00 when the temperature went below 0 degrees at the week end. We just scraped by however, don’t want none of those freezing temperatures ‘round ‘ere, not no how thanks! Regards, Toodles.

@toodles thanks, interesting to hear. I'm not expecting to be able to shift all of our demand into the cheap periods, by any means, but should be able to start making a small dent as soon as my Cosy switch happens, followed by a more sizeable one once our battery gets installed.

Also have a large delivery of supplies coming this week to give the loft insulation a boost. Would have be been lovely to have all of this in place before this winter, but hey ho, will keep chipping away!

Cheers,

Jo

@josephiah The best time to have installed renewable energy projects is always ‘Last Year’! 😄 Regards, Toodles.

@toodles Quite. I'd first looked at all this seriously back in 2021, but then life got busy and I didn't follow through - man, I was kicking myself last winter. I guess a more positive spin would be that last winter finally kicked me into action!

@josephiah I first started researching the whole subject of ‘going green’ back in the dark cold months at the end of 2020 and well into 2021. I wanted to ‘go solar’ first but of course, I first needed to consider any improvements to insulation thus had Q-Bot underfloor insulation downstairs and at the end of this work looked into increasing loft insulation to 300 mm+ in the autumn of 2021.

PV took months to sort (about 9) before installation in July-Aug. 2022 and had to wait until November of that year for the first Powerwall. The ASHP was ordered in Dec 2022 and installed mid-February 2023; a few months later, I had the second Powerwall added. I have been supplied by Octopus Energy since July 2022 and not regretted it at all!

I checked the last week’s consumption up to last night and the daily average over that week works out to be 45.45 kW/h. With care, I can use the battery capacity to ‘download’ at cheap rate and eek it out without reversion to any higher rate energy. From this, I would reckon my daily consumption for heating + DHW heating plus all domestic needs is costing me approx. £7.50 plus the despicable standing charge of course! No gas so that’s it in total. Not much solar energy from the 8.1 kWp. array at present but this will be sold back when any surplus shows up. Regards, Toodles.

My 9kW Cool Energy (SPRSUN) has been coping admirably this last week.

Rads in the old part of the house, ufh in the 15m2 extension. Weather comp curve 37@15, 48@0…. No buffer, no separation, no thermostat.

Our very worse day was 56kWh for the whole house, and that included 1.5 charges of my ampera and four loads od laundry.

House is warmer than it was before, and it doesn’t cost any more.