Joining the Renewable Heating Hub forums is completely free and only takes a minute. By registering you’ll be able to ask questions, join discussions, follow topics you’re interested in, bookmark useful threads and receive notifications when someone replies. Non-registered members also do not have access to our AI features. When choosing your username, please note that it cannot be changed later, so we recommend avoiding brand or product names. Before registering, please take a moment to read the Forum Rules & Terms of Use so we can keep the community helpful, respectful and informative for everyone. Thanks for joining!
Looking at putting in a PV system
Hi , quick intro
I am an electro/ mech engineer (dirty hands)
Midlands uk based
Looking at a PV system next year so it’s a very steep learning curve for now .
Hoping to learn and help in any way I can
Regards Jeff
Welcome to the forums Jeff. Good luck with your PV installation. Did you have any initial questions or do you have an idea of what you'll be proceeding with in terms of kit, brands and size of array?
New to heat pumps? Take the Heat Pump Fundamentals course and use INTRO50 at checkout for 50% off.
Rewritten and updated for 2027
📘 From Zero to Heat Pump Hero
🛠️ Bodge Buster
Thank you for the welcome .
Getting my head around all the components and options but …
If I get limited to G98 can I still max out on panels ?
Do I then have a big inverter with an export limiter ?
Assume 8kW panels - 2 usage , 3.6 export where does the rest go ?
if the panels are making energy I assume it has to go somewhere , battery full , export maxed, all appliances on - where does the excess go ?
Regards Jeff
Hi Jeff. Solar PV panels are now £0.50 per watt, electricity cost is only going in one direction, so max out all available roof space. Exporting power is a mugs game now, you get pennies for what you generate and your electricity provider sells that on as a massive profit. Someone else pays the price capped standard rate/kWh for what you micro generate and get paid 4p/kWh for! Don't give them the satisfaction. Use what you can, store what you can in batteries. If you have a system tank with an immersion heater, get a solar diverter like an I-boost. That will dump surplus electricity into your immersion - free hot water in summer, and very helpful even in winter. If you've maxed out on export and are generating more than you can use or store instantaneously, your system inverter will simply limit the solar PV output to 3.68kW to grid.
Batteries are not cheap, and the global demand for lithium batteries will keep prices high and handsome, but if you can't afford the initial capital outlay for battery storage, get a hybrid inverter that's battery ready and allow space for batteries. I had 3.6kW PV installed October, and planned to defer the 6.5kWh battery until Spring, but I think battery prices are going to rise next year quite significantly, so I'm getting a battery fitted early in the New Year. Won't really be of benefit to me until mid Spring however.
I think that at the moment if you have a battery system installed at the same time as solar PV, you can save the VAT on both.
Hello, I can confirm that having a battery ordered within the same contract as that for PV will allow the contractor to apply zero rate VAT to the battery system as well. Ordered on its’ own, the battery will have VAT applied to it and its’ installation cost. As to whether it is worth trying to export your surplus energy (and I stress ‘surplus’), this is indeed worthwhile with the right tariff. I am with Octopus Energy and have the Agile tariff and export using the Outgoing Agile; under this scheme, the amount paid per kW/hour will vary but I reckon my average unit rate has been in excess of 20pence. I received over £200 credit in the space of less than 2 months production last August and September. I hadn’t the means to store my excess energy then but now have a Tesla Powerwall; however though I turn on the immersion heater and try to ‘soak up’ my sunny weather excess with a convection heater, I still find that Octopus have credited me with a few pounds in a month. I have 8.1 kWp. of PV and am to have an ASHP in a few weeks and an Eddi diverter will be fitted at the same time. I am having a Sunamp Thermino ePV 210 (short of space for a large tank!) and this will be connected to the Eddi and by this means, my DHW will be catered for by PV power with grid backup if needed. Regards, Toodles
Toodles, heats his home with cold draughts and cooks food with magnets.
Oh! And as a sort of post script: My MCS registered installer applied to my DNO with a G99 form - took the usual long period of time but was granted and I am now able to export up to 5kW. I know of others who have a 3 phase supply and can then have plural Powerwalls allowing for greater storage and export allowance. This is an expensive game mind you and probably not worth it if your sole aim would be to export more energy! Regards, Toodles
Toodles, heats his home with cold draughts and cooks food with magnets.
Listed Grade 2 building with large modern extension.
LG Therma V 16kw ASHP
Underfloor heating + Rads
8.7kw pv solar
3 x 8.2kw GivEnergy batteries
1 x GivEnergy Gen1 hybrid 5.0kw inverter
Manual changeover EPS
MG4 EV
- 27 Forums
- 2,746 Topics
- 64.5 K Posts
- 368 Online
- 7,149 Members
Join Us!
Installer Finder
Degrees of Separation
Latest Posts
-
Have you considered keeping your FF boiler and suppleme...
By Old_Scientist , 53 minutes ago
-
RE: Who's your electricity provider and what's your tariff?
@toodles I invested on Miele a pair of frodge frozor wh...
By AgentGeorge , 2 hours ago
-
RE: Flushing system, cleaning and inhibitor
Flush and fill all complete. Octopus kindly gave us a...
By Old_Scientist , 3 hours ago
-
RE: Wood burner with ASHP - direct air?
For what it's worth I installed a wood burner in this o...
By BlizzardGreen , 4 hours ago
-
@editor Thanks for your response and recommendations. ...
By DavidB , 11 hours ago
-
RE: Do I add Air Con or MVHR to existing A2W ASHP?
I think I saw a diagram for an exhaust air dhw tank wit...
By JamesPa , 1 day ago
-
RE: Indevolt Batteries UK Support & Info Thread
Thanks, however that's an answer to a subtly different ...
By JamesPa , 3 days ago
-
RE: Solar Power Output – Let’s Compare Generation Figures
@toodles Such elegant symmetry. look at my lumpy bag of...
By Papahuhu , 4 days ago
-
RE: PV and battery long payback - sense check query
Quite probably not, but you can get a 32A relay and a S...
By JamesPa , 4 days ago
-
RE: Starting Our Heat Pump Journey: 1962 build 3 bed detached house
@ian-s Look forward to making contact soon! Regards, To...
By Toodles , 4 days ago
-
I don't notice mine defrosting, and most of the time Im...
By JamesPa , 5 days ago
-
RE: Do I need to change the control unit when replacing my Ecodan Air Source Heat Pump
Kind of you, @calumm, but it was @f1p who did the heavy...
By Majordennisbloodnok , 6 days ago





