How much are Solar Panels worth

Blackrock1 said:
completely wrong is a bit definitive.
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It is definitive but for argument sake, lets use the unit rates that @FANTANA and many others use to overestimate the payback.

For 6 months of the year (April - September) , the system should produce an average of 650 kWh per month or 21.5kWh per day. They will now add 12.5kWh to that from an overnight charged battery.

That's 34kWh of usable electricity during daytime hours. For reference, we are also an all electric household for domestic use and heat pump. For those 6 months we average 13 unit per day with 8 units on the daytime hours. Unless I'm not mistaken, every single unit from the battery will go straight back to the FIT.

Even in the tail months of Feb, Mar, Oct, and Nov, our own daytime usage creeps up to 15 units on average as the HP does more work. The solar should still be generating 12.5 units along with the batteries 12.5 so still an excess of 10 units going to FIT.

I don't believe fantana has a heatpump so if their domestic use is more typical like the CRU's 4200 then pretty much all of the battery use for 9 months of the year is going to FIT as well as some in winter months. The savings is closer to €450-500

The point of all of this is to show that the vast majority overestimate their savings. Fantana has a great setup but the value has come from the massively reducing cost of batteries, the DIY install, comparing the wrong unit rates and by choosing to ignore the upfront costs when installing solar to allow the battery to be added.

Blackrock1 said:
If i had a 16kwh battery and i diverted day usage to night it should save me circa 1.72 a day or 630 a year. Take 15% off (which i think is high) for days in the summer when i cant fully utilise the battery in a day (but would also charge less) its still around 535, you'd pay the battery back in 3 years.
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In my approach it is still possible to land on the same plan when assessing the impact. This would typically happen when usage is high like yours (EV&HP) and either solar only or battery only is implemented.

To finish with a quote I've seen on AAM and I think it was from @Micks'r , "the cheapest unit is the one you don't use".

There are so many people who are very inefficient with their energy use before they install solar. This arbitrarily inflates the payback because it gets included in the calculation but that saving can be made independently. Similarly with switching provider every year. That is a 'free' saving that shouldn't be assigned to solar.

I'm a fan of solar/battery but I laugh when I see people claiming payback of less than 5-6 years.
 
_OkGo_ said:
There are so many people who are very inefficient with their energy use before they install solar. This arbitrarily inflates the payback because it gets included in the calculation but that saving can be made independently.
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I can't get my wife and kids to change their energy usage profiles and believe me, I've tried!!! Sometimes your family usage just is what it is!
 
Used to pay ~1600 or so per year. Got 13 panels installed for 7k a few years back when they removed the VAT charges and including the grant discount.
Yearly bill effectively 0 more or less now. I am in credit for 800eur at the moment due to the government energy grants building it up. Was a no brainer at the time. Insanely good returns and tax free.
 
Purple said:
I think my wife is afraid of the dark. Once it gets slightly dark every light in the house is on all of the time.
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It’s the other way around in our house, my wife has a concept of ‘nice light’ i.e. little lamps all over the place. I like to be able to see, I would put neon strips everywhere if I could.
 
One thing not to forget is the hobby factor. A lot of people getting solar panels (myself) are nerds and playing around, eaking every last bit out of the system is fun. Doing a wash from sunshine electricity is satisfying.

My father had a point too - these systems are indeed designed to NOT work if there is a power cut just so the system doesn't export electricity into lines that the ESB engineers think are switched off. But that can be changed easily enough so in the event of mass power cuts - war, terrorism, gas plants break down, something like that... you have electricity of some sort.

So don't forget those two in your calculations.
 
In 2024, my electricity bill was around 2000€. This was for a house with a heat pump, and I had a petrol car, up until November. It was then replaced by an electric one (but I do only around 8k kms a year).
22 solar panels installed in the beginning of March 2025, for around 11k after grant, with no battery. East 12panels, West 10 panels. For the whole of 2025, including electric car and heatpump, my total electricity bill was 800€

A broad brush-stroke example, but shows that my total energy bill, including transport, and heating etc. is only 800€

At this rate, the payback period is around 8 years.
 
nest egg said:
Looking at a similar setup, how much electricity did you generate last year?
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I changed suppliers, so can't get it from old supplier. But according to Soliscloud, I generated 6325kWh in 2025. This is not completely accurate as the measuring clamps were reversed for a short while. It's also from March to end of year, so not a full year. Here's the graph, which shows the year. As I have a heatpump, you can see the consumption rise in the end of the year. Inline image
 
I also noted you don't have a battery, did you consider it?

All of the installers are pushing them, from what I can see, however I can't see the benefit in our case, while FIT rates are what they are.
 
Buddyboy said:
I changed suppliers, so can't get it from old supplier.
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Does your smart meter data not reflect exported units?

ESB Networks meter services for your electricity | ESB Networks

Access ESB Networks meter services in one place. Get guidance on smart meters, meter readings, moving or adding a meter, and all essential meter support.
www.esbnetworks.ie www.esbnetworks.ie
Edit: looks like it should do...

My energy consumption

www.esbnetworks.ie www.esbnetworks.ie
What electricity information is available through my ESB Networks Online Account?

With a smart meter, you will be able to view and download details of the electricity you have used across the day, week, month or year. In addition, customers with microgeneration (customers who generate their own electricity e.g. using solar panels) will also be able to view and download the electricity they have exported to the grid.
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Pawel Nowak said:
Peemac get more quotes.
I got 15 panels 6.4kwp with a 10kwh Dyness battery and a solis inverter in October for 8250 after the grant, ber included
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Have 12 panel (max for roof) + inverter + 10kw battery + BER agreed at 8250 after grant. Its a slate roof, so that's where an extra cost is involved. If regular tiles, it would be almost €1000 less. Went with one of the larger outfits due to the slate tile issue.
 
nest egg said:
I also noted you don't have a battery, did you consider it?

All of the installers are pushing them, from what I can see, however I can't see the benefit in our case, while FIT rates are what they are.
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My installer suggested waiting for a year before getting the battery, to see what the data was re use etc.

You are correct, with FIT rates at the moment, I'm selling all excess to the grid. I don't even use the Eddie to heat water as I get 19.5c per Kw from the grid, and I use the Heatpump during the night (at night rate) to heat the water, which is also 300% more efficient. I also charge the car at night rather than using solar surplus, again night rate of 13c rather than opportunity cost of 19.5c *

I am still on a day/night tariff and it's still around the cheapest. With the heat pump operating at different times during the night, I don't have to worry about cheap electric windows. I put my usage through energy pal and it's still pretty competitive. I changed from Electric Ireland to Flogas this year. It's definitely worth checking each year to check rates.

* One thing that did happen occasionally during the Summer. Our neighbour, on the same line to the road, also has panels, and at times of high solar generation, the inverter started rebooting. I discovered the voltage on the line was too high for the inverter to feed into it. To combat this, I set the eddi to heat water using the surplus, and plugged in the car, also set to use the surplus. I also don't want to go over the tax exemption for micro generation.

If the FIT changes, or other variable, I will get a battery. In the meantime I'm in effect using the grid as my battery.
 
Buddyboy said:
If the FIT changes, or other variable, I will get a battery. In the meantime I'm in effect using the grid as my battery.
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I was considering a second battery at install. Prices were roughly €3k for 9kwh at install. €4.5k to do later.

Seems mad. There is 13.5% vat but that’s still €1k for a call out.
 
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Buddyboy said:
My installer suggested waiting for a year before getting the battery, to see what the data was re use etc.
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I think we may do similar, which wasn't what I expected when we first started to look at solar systems. If anything, I saw an arbitrage opportunity, i.e. buy electricity for less (over night), than we could resell it for (during the day). However the system we would install will easily generate €800 in electricity over the year with the panels alone. As we would have to pay tax over that amount (with two people on the bill), the battery would end up costing us money.
  • Buy: 14.64c x 9 units = €1.32.
  • Gross Income: 8.1 units (90% efficiency) x 19.5c = €1.58.
  • Tax: 52.2% of €1.58 income = - €0.82.
  • Net Income: €1.58 - €0.82 = €0.76.
  • Result: Spent €1.32 to earn €0.76
 
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