Solar Panel and Battery options for very high energy use family.

samkellylou

Hi, 

Looking into Solar panels and battery options.

We have very high usage over past 12 months we have used 1488kwh a whopping  £3,448.95 !!!!!

My usage breakdown for feb 2025 to feb 2026 was 7,742kwh day rate and 7059 for night rate.

 

We live in an old property (1850 and extension in 1900 build) so have two roofs with a valley connecting. We run underfloor heating downstairs, have an air source heat pump to heat an outdoor swimming pool in the summer (May to Sept), Charge an EV via a pod point connection, a klargester sewage treatment unit as we are not on mains sewers and two young adults who use every socket / charger going !!

 

We have had one national company come out so far to talk with use and another local company to complete site survey quote not in as yet. I had another national company come but left swiftly when they realised they had based their figures on the property down the road. 

 

I have been told that the maximum we can generate annually would be 5,484kWh and our annual usage would be 4,113kWh with use exporting back to the grid 1,371kWh.  

12 panels (500w each) and an 8.6kWh energy cube battery.

 

They also shared that off-peak energy charges battery for us to top up during the day 2655kWh. 

 

With projections

Current Annual Electricity Spend	Solar Energy And Export Savings	Combined Battery Benefits
£3,448.95	£1,574.05	£628.92

 

Can I ask as we will only be able to produce 1/3 of our energy is solar a realistic alternative for us as I am unsure on what the charges would be for use to buy back energy from the electric company and will an 8.6kWh be enough for our family usage ? 

SimonSeys

I have a 32kWh battery from Fogstar. You will need an inverter too - mine is 8kW. I charge at 8p /kWh using octopus intelligent octopus go. I charge the Ev at the same time.

I only use the battery between 20% and 80% of capacity, but that’s easily enough to run the entire house. If it’s not enough for you you can get a bigger battery and inverter.

I used a local electrician to install it. They do not need to be MCS registered. You do need someone MCS. registered to install solar.

Whole thing cost me around £7k installed (don’t have exact price as we did other work at the same time).

There are of course other options available.

QrizB

You are a huge consumer of electricity.

If you'd posted over on the Energy board asking for advice you'd have been told that direct electric underfloor heating is one of the most expensive forms of heating available, and heating a swimming pool is just throwing money away. However, as you're not actually complaining about the bills being unaffordable I'm going to assume you've got an income that accommodates this and you're not really interested in reducing your electricity use, just in reducing the bills.

We live in an old property (1850 and extension in 1900 build) so have two roofs with a valley connecting.

If you're hoping to put solar on your roof, it'll all depend on how complicated the roof structure is. Two plain apex roofs with a valley would give you a lot of area for solar PV; if your roofs are hipped, or are full of dormers, skylights and chimneys then the available area will be reduced.

Nevertheless, 12 panels seems quite a low number. I'd have hoped you'd have room for twice that number.

I'd also suggest that 8.6kWh of battery is hardly going to touch your use. You're using ~40 kWh a day on average, and in your position I'd be looking to fit at least 20kWh of battery and preferably more - enough that, in the winter, you can charge it on your off-peak tariff and then get through the day on battery only.

born_again

As above you need a far bigger battery & a tariff that gives cheap off peak to charge it up over night (notice you split to peak/off peak) but no idea what tariff.

Have a look at Andrew Till/Mr EV on u-tube. He had high usage & has13kW solar & 20KW battery & battery runs out many days

Screwdriva

Solar + Batteries are an obvious solution for you. That said, I would focus your search on finding the right installer who will do their homework to maximize the generative potential of your roof while supplying the best possible brands of panel and battery inverter for a positive ownership experience over the lifetime of the system. Finding this rare breed of installer has a much more direct result on your system's performance (vs. their proximity to your roof).

If you can share an image or two of your roof (either from ground level or Google Earth), I can share a realistic number of panels that may fit. Also would be good to know where in the country you're located.

NedS

https://forums.moneysavingexpert.com/discussion/comment/81950742#Comment_81950742

I agree. Given the energy use and complexity of your situation, a really good local installer is the way to go. One who will really take the time to understand your use case and maximise the potential.

Are you on a single phase connection or 3-phase?

greenbee

The good thing about heating the pool is that you’ll have somewhere for all your excess generation to go in the summer if you max out the generation to support your winter use!

As @Screwdriva says, images of your roof with an idea of orientation would be helpful to understand where you could put panels (also any suitable outbuildings), and you would definitely benefit from more battery storage, so the right installer is important. Including someone who understands your UFH - as @QrizB says, if this is electric UFH then it will always be expensive to run. Do you have other non-electric heating?

I found that the energy companies just offered their standard options and didn’t want to discuss options. The local ‘solar specialists’ were better, but I ended up going with a local electrician (who also installs for one of the energy companies) who talked through a number of options with me - we ended up installing in two phases (complicated roof meant scaffolding wasn’t going to cost more if we did them together or separately). If I’d been more confident (and had the cash!) I’d have done it all at once.

I have 20 south facing panels (14 on the single storey garage which has least shading, 6 on south-facing main roof, which is shaded from the east by a wood, and 9 on the west-facing roof). This gives me more than enough (I’ve been generating up to 10kW at any one time already this year, and had some 60kWh days) for most of the year, although if I didn’t have a wood to the east I’d put more on there to extend the day. No EV yet, no ASHP although one is planned and I’ll increase the battery storage at the same time. No swimming pool, although it would be handy to have one in the summer to make use of all that excess generation!

samkellylou

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IMG_3868.jpeg

In response to some of the questions above.

We are south facing (-4 degrees) by what the chap said that came and gave the above quote. We are a semi detached with family in the next door property but not able to use their half of roof.

Single phase connection with an upgraded 100amp fuse I believe as we had to have it upgraded in 2011 when we had an induction oven.

Under floor heating is electric and runs through 1/3 of ground floor. We have an oil boiler and radiators in the two other rooms downs stairs with the hallway and downs stairs hallway with no form of heating and an old open fire and radiator in the living room.

There are outbuildings but this is detached from the property and only wood and metal roofs - see photo 4.

IMG_3887.jpeg

samkellylou

https://forums.moneysavingexpert.com/discussion/comment/81950629#Comment_81950629

I'm happy to learn more about reducing consumption, but living in an old house comes with its challenges. I try and make my money stretch to the best of my ability,

Reed_Richards

Sorry If I am being picky but if

 over past 12 months we have used 1488kwh a whopping  £3,448.95 !!!!!

then you are paying £2.34 per kWh!!! My guess is that your actual electricity consumption must be 10 times the number you state. Getting the numbers right will greatly aid your cost-saving calculations.

QrizB

Sorry If I am being picky

The two individual consumption values for the two rates, "7,742kwh day rate and 7059 for night rate", sum to 14801. This is consistent with the OPs total cost.

Yes they missed a digit, but they've given enough extra information that we can error-correct.