Marvin

Hi @Huckleberrys Be aware that different DNO's seem to have different rules. If your unrestricted inverter will work up to 8kW then that is an 8kW system. (its not about the total panel wattage - often you can add more panels than the stated rate of the inverter - check the inverter installation instructions for details) If the battery storage goes through the inverter to be used, then, as far as I understand, it's still considered a 8kW system. If the battery storage does not need the main PV inverter to produce energy used in your mains system (another inverter for the battery power) then as far as I understand that power will need to be added to the 8kW PV inverter. This all being said I'm sure someone will correct me if I'm wrong, however for ours with Scottish and Southern, this was the way it worked. We had to pay for the survey. Some others haven't. Be aware that if you upgrade your system (bigger or more inverters connected to the mains) you will need to apply again And finally the only other ways I know not to go through this is to have a system that is completely off grid. Good luck M

+1 with @JohnMo

Hi @DragonQ At what rate are you proposing to charge your EV? We have PV and an EV and experience charging using mainly the PV.

Hi @GraHal In my humble opinion, I would want one with 2 pipes (an inlet and an outlet) or with a concentric pipe. Our MVHR whole house system runs the warm air out, heating one side of a temperature transfer thing, whilst the fresh air coming in picks up the heat from the orherside of the temperature transfer thing at the same time. This warms the incoming air in winter. Although it may be the single ones your looking at operate differently. Can you post a link? M

Yes my friend... but I want to cut my hair...

I think the problem comes back to no switches allowed because of possible wet hands, like the light switch in the room being a pull chord. I'm certainly fed up with dragging an extension lead in and it being a trip hazard. I still think the zoning applies: "Electrical sockets are permitted in bathrooms or shower rooms as long as they are located more than 3m from the edge of the bath or shower." Well that excludes us then!

Hi @KelvinI think your right. However, I though Amenity Land was a requirement of the planning requirements of the development and therefore couldn't be changed???

I'm not quite that that bad. All I want is to not waste energy keeping our home warm/cool https://www.bbc.co.uk/news/business-64261457

I thought the law had changed on this..

Hi @retrospective-build Yes. Pictures would help. I dropped ours through the soffit. If the pipework is outside the thermal envelope I would keep it as short as possible to avoid overheating the air in the summer and insulate like mad. I assume you know to keep the inlet outlet apart...

very cloudy

Hi @Drellingore Daily results for our 5.12kW system this January: Date energy 01/01/2023 1.36 02/01/2023 12.24 03/01/2023 0.45 04/01/2023 1.07 05/01/2023 3.00 06/01/2023 2.52 07/01/2023 3.00 08/01/2023 1.54 09/01/2023 8.42 10/01/2023 0.22 11/01/2023 4.33 12/01/2023 0.00 13/01/2023 12.31 14/01/2023 2.17 15/01/2023 7.52 16/01/2023 6.63 17/01/2023 2.62 18/01/2023 11.80 19/01/2023 14.16 So as @jack points out: its not a constant flow of energy. We looked at off grid and keeping our lifestyle... ho ho! Forget it without massive storage. If we covered all the roof both sides, the front and back garden and everything there would still be inadequate panel surface to supply what we require in the winter. I am with @Radian and wait for decentralised generation and more importantly decentralised storage. I also agree with @ProDave philosophy about self use being king.

Sounds good. As @jack just said... Have you considered the distribution network operator (DNO) requirement for such a large system? it look like about 100amps.

Hi @Drellingore Er... just checking... Our 5.12kW system produces about 200kWh for the whole of December, so I 'm just wondering if you've taken into account the reduction in energy over the winter peroid. Here is our PV's energy production over the last year in months using a 5.12kW system Month kWh Jan 204 Feb 294 Mar 601 Apr 744 May 818 Jun 902 Jul 816 Aug 770 Sep 536 Oct 362 Nov 296 Dec 171 Good luck M

Splitting away from the "Turning our heat pump off over summer and a general moan" thread.... 19 hours ago, Marvin said: I would recommend checking out a solar diverter to anyone who has PV and a hot water tank with an immersion. Phil T Responded: I did give this a lot of though and decided against as I get 15p fixed SEG, my heat pump is doing better than COP of 3 for DHW, so at my current variable electricity rates 33p it would cost me 4p/kWh to use a solar diverter instead of the heat pump, or cost me 8p/kWh assuming "Cosy" rate 21p/kWh, and that's before taking into account the up front cost of the diverter (a few hundred quid?). Have I got that logic correct or am I talking complete cobblers? Hi @PhilT No. Your thoughts make sense. You've checked out about a solar diverter and decided its not for you. I forgot all the possible setup differences which mean it is better for some than others: We do not have a smart meter. We do not get paid for exporting. We have one rate for electricity.

Hi @RogerH You have my sympathy. We have had to do the same. The mix of technologies now being installed in homes has only recently started to come together and the biggest hurdle I see, in trying to make it all work together, is that the answer can change for each individual property and its use. As for turning off the ASHP: You are fine turning off your ASHP, however consider this when turning back on: If the outside temperature has been below 5 Centigrade in the last 12 hours the liquids in the compressor in the outside unit could be too cold for the unit to work properly. If this is the case you need to leave the system on standby for 12 hours for it to warm up. I do not know which Ecodan you have but here is an Ecodan instruction manual. See section 7: Test run. https://library.mitsubishielectric.co.uk/pdf/book/Ecodan_PUHZ-_H_W_Installation_Manual__BH79D532H03_#page-7 Different ASHP have different ways to solve this technical problem so check with your own model instruction manual. As @JamesPa has started asking, to help with the question of how to improve your ASHP efficiency, we would need to know a lot more about what system has been installed. Personally I would have started with the physical aspects in detail. What is the make and model of your ASHP Is the ASHP connected to a buffer tank. If so, what size in litres, where is the buffer tank in the building, how long is the pipe distance between the ASHP and the buffer tank. Photos would help What is the ASHP feeding. Obviously not water, radiators? underfloor heating? If underfloor heating what thickness is the insulation under the floor and what type. ASHP efficiency is related to the principle of low and slow: Low heat, slowly warming the property. If you do the opposite your COP will drop dramatically. Bearing this in mind any little leak of heat becomes important to avoid. The main pipes from the ASHP I have insulated to within an inch of their lives! Good luck M

Usually this is because the foam canaster is too cold.

You miss the point. Quite surprising for you SteamyTea. Perhaps it me.

IMHO this is a bit of muddled logic. Our diverter only diverts excess energy from our PV. Excess PV is all the bits which are not used and would otherwise go to the grid. Our diverter can channel 200 Watts for hours to the immersion heating up the water. It can also channel 3kW for 30 seconds. Neither of these energy profiles would produce more heat in the hot water tank using our ASHP. Our ASHP will not run on less than about 700Watts, but the diverter would stop these bits of energy from going to the grid and use them heating the water. During the winter months we have often heated the hot water on little more than the odd cloud break or the spare energy in between the ASHP cycling. I would recommend checking out a solar diverter to anyone who has PV and a hot water tank with an immersion.

We don't turn the MVHR off because we would have moisture issues in the ensuite, however, this year we aim to run the MVHR solely from PV, all year.

Hi @dnb Our weather is often so variable during a day ( in relation to sun and wind) that we've given up trying to predict it. Using brush strokes has been our best strategy. Using the results from the PGIS on a monthly basis has given us a general picture of what to expect regarding PV energy production. Here's our results for last year: Year Settings 2022 ERA5 6% loss Running Act sub diff % kWh Total Jan 2022 216 216 204 204 -12 94.4% Feb 2022 316 532 294 498 -22 93.6% Mar 2022 552 1,084 601 1099 49 101.4% Apr 2022 774 1,858 744 1843 -30 99.2% May 2022 809 2,667 818 2661 9 99.8% Jun 2022 821 3,488 902 3562 81 102.1% Jul 2022 836 4,324 816 4379 -20 101.3% Aug 2022 724 5,048 770 5149 46 102.0% Sep 2022 582 5,630 536 5603 -46 99.5% Oct 2022 393 6,023 362 5965 -31 99.0% Nov 2022 252 6,275 296 6262 44 99.8% Dec 2022 190 6,465 171 6433 -19 99.5% So in the year we produced 99.5% of what was expected. Temperatures are reasonably as expected except for the wind chill factor! We think that the winter production is lower than estimated because we are in a shallow with higher ground to the east and west so during the winter a bigger percentage is not produced. Again, if we decide to cook a cake for instance, because of the good insulation this can overheat the bungalow. Solar gain? Vacuuming! Ironing! Jolly good argument! All heat the house. Too many variables for my liking. I am now concentrating on reducing the purchased overnight energy using battery storage.

Hi @Alan Ambrose Do you have a water tank in the loft or a header tank for the heating?

Yes we have. Works fine on old style night storage heater. Spoke to company and they heat the office like that when spare energy available after heating hot water tank. I think they have a oil heater. As long as ALL the energy is used for resistive purposes. I.e purely heating a electric bar, not controlling like a timer etc.

Hi @RichardL Yes. SWMBO needs to be able to use it when I'm away. There's two camps on the choices of controls. Some new wave, some old school. You'll have to guess which camp we're in!

The aim with the hot water tank is to over heat it enough with otherwise unused energy so it lasts a few days. At present the PV runs at a good day (for winter) then 3 poor days, or about average day after day, or a mix of the 2. Yes we have to adjust things depending on the temperature etc, to achieve the best performance....