has anyone managed to offset their ESB bill with solar alone?

tom1ie · 20-03-2026 05:01PM #1

hi all,

First off apologies if this has been asked before, so feel free to point me in the direction of an existing thread.

Basically I want to know is it possible to get all my electricity demands plus heating and hot water (gas bill is massive!) from Solar and a battery and has anyone on here done it.

Background:

2 adults, 1 teenager and 2 kids in a 4 bed south facing semi d.

Dormer on the south side of roof so not sure if Solar can be put on a dormer roof?

No EV's yet but I would definitely consider getting rid of the 2x Diesels for an EV or two depending on price.

Haven't figured out my base load demand of electricity but its on my to do list.

any thoughts?

CuriousCucumber · 20-03-2026 05:16PM

We live in a 4 bed semi, A-rated house.

Have 15 panels, and a battery.

Haven't paid a bill in over 2 years. We're currently, just about in credit after the winter. That will build up again throughout the summer. Today alone, we've used nothing from the grid, and sold back around €9

Have a plug in hybrid at home that gets charged every 2 or 3 days overnight

tom1ie · 20-03-2026 05:47PM

https://www.boards.ie/discussion/comment/124327447#Comment_124327447

excellent.
Ours would be a 1965 era semi d but I’ve had 50mm insulated slab put on the inside of the outside walls, 10 years ago.
Layers of insulation in the attic and as I say the dormer done.
When you say haven’t paid a bill in 2 years, is there no standard connection fee that has to be paid regardless or does the Feed in that you provide to the grid offset this?

CuriousCucumber · 20-03-2026 06:14PM

https://www.boards.ie/discussion/comment/124327535#Comment_124327535

The energy we return to the grid covers all of our costs.

tom1ie · 20-03-2026 06:39PM

https://www.boards.ie/discussion/comment/124327595#Comment_124327595

Excellent thanks for that info.
Do you have hot water from your immersion or do you get the hot water from gas?
I find that our Gas bill is very expensive and I’m interested to see can electricity replace gas for hot water and if possible heating.

JohnySwan · 20-03-2026 06:46PM

We installed 2 Air to Air heat pumps, 26 pv panels with 26kwh battery and have 2 Ev's. €1,500 in credit with EI. Disconnected the gas over a year ago.

Edit: We have an electric shower and water for baths is via immersion.

graememk · 20-03-2026 07:39PM

https://www.boards.ie/discussion/comment/124327649#Comment_124327649

Gas is cheaper to heat hot water than an immersion, even on the EV rate there isn't much in it.

If you pull up your gas bills for the year and see your use, that's the kWh that you would have to replace with electric.

Even going heat pump route and done no other changes, and you got a COP of 4

Take your gas use and divide by 4 for a rough estimate of how much electricity would be used instead of gas.. (and then work out cost with your electric rate etc)

That all being said, solar is worth it and in some cases can offset the electricity bill completely

tom1ie · 20-03-2026 07:39PM

https://www.boards.ie/discussion/comment/124327670#Comment_124327670

Thanks Johnny.
This is exactly what I was looking for.
Do you mind giving me a ball park figure of how much I’d be looking at to do that.
I don’t think the heating will work as it’s an old enough house etc but everything else I’d be very interested in.
If the repayments on a loan were in and around what we are spending on gas, electricity and diesel then it would be game on.

JohnySwan · 20-03-2026 08:00PM

https://www.boards.ie/discussion/comment/124327792#Comment_124327792

I would say somewhere around 16/17k to do it, but not I'm too sure as I did it all myself.

unkel · 20-03-2026 11:23PM

https://www.boards.ie/discussion/2058436123/has-anyone-managed-to-offset-their-esb-bill-with-solar-alone

My total annual electricity bill, including 4 EVs, is negative enough to pay for my total annual gas bill as well. So no more bills. Not for gas, not for electricity, not for fuel.

The system has been 10 years in the making with most of it DIY. So can't really tell you the exact cost off the top of my head. But it has all fully paid for itself by now. And before you ask, I live in a modest 3 bed semi home in Lucan, one of the cheaper suburbs of Dublin. Panels on all my house roof surfaces and on my large shed. Powerful inverter setup with very big battery. System is run fully automatically on Home Assistant server (old laptop), most coding done by ChatGPT. I make most money because of the very generous feed in tariff of 25c / kWh. And the super low electricity rate of 6c / kWh

tom1ie · 21-03-2026 01:07AM

https://www.boards.ie/discussion/comment/124328576#Comment_124328576

Honestly I don’t know what most of that means!! How do I replicate this?

unkel · 21-03-2026 01:15AM

https://www.boards.ie/discussion/comment/124328852#Comment_124328852

Get a subsidy PV install, starts at about €7k after grants. But upgrade it so they will put PV everywhere on all your roofs and even more. On walls, groundmounts, wherever you can. Join Pinergy. Get a big battery (minimum 20kWh). Procure an old laptop or PC (€50 max), install home assistant on it and ask Chat GPT to program some automations for you

Just to give you an idea of the outcome. My system is currently automatically still dumping the last of my battery into the grid at 3kW. My SOC is 22%. Once it goes under 20% it will stop. Then when 2AM comes (happy hour), my system will go into overdrive, charging everything, my cars, my battery, my hot water on supercheap 6c night rate. As soon as happy hour is over at 5AM, the system automatically starts selling all that cheap electricity back to the grid at 400% profit. And if / when the sun comes up that day, it will start exporting all or most of that to the grid too. But you will have to jump into the deep end. Nobody is going to set this up for you. It has never been easier though. AI will take your hand and help you every step of the way…

Ardent · 21-03-2026 01:48AM

@unkel which provider are you with that gives you 6c/kwh between 2 and 5 am?

unkel · 21-03-2026 02:04AM

https://www.boards.ie/discussion/comment/124328911#Comment_124328911

It's in my earlier post of today. Pinergy. 6c / kWh incl. VAT between 2AM and 5AM (best rate of them all) and 25c / kWh incl. VAT for feed in tariff (also the best rate of them all)

I have been with them since 5 minutes after my smart meter was installed well over 2.5 years ago. Made a small fortune from them. Long may it last, but all my systems have already fully paid for themselves

Ardent · 21-03-2026 02:09AM

Interesting, thanks. It's also interesting that you're a total EV convert - I remember you as a car enthusiast from your many posts on the Motors forum many years ago.

unkel · 21-03-2026 02:29AM

https://www.boards.ie/discussion/comment/124328928#Comment_124328928

I still am. Sold my classic Lotus Elan turbo less than a year ago, still miss it. Looks like I might buy another petrol convertible soon enough again. Have owned many very nice cars, V8 petrol is my favourite engine of all time. As you would call it, I am a petrol head. Or was. But I will always be a car enthusiast

There is no mistaking the future though. I have a large fully electric camper van with a big battery. It costs me €3 to charge it up from empty to full. How much diesel does that buy, a bit over one liter?

EVs have been a no brainer when it comes to total cost of ownership for many many years now. It takes a bit of an oil crisis for all the thick people out there to wake up maybe…

Eggs For Dinner · 21-03-2026 08:32AM

Installed 12 panels (no battery) in Jan 23. I haven't paid for electricity, standing charges or VAT since March 23. My current bill is showing €124 credit. That takes into account the government credits we all got last year.

For context, we are a retired couple and the only ones in the house. Our heating is oil and a stove. We swim in a leisure centre every day and use their facilities for showerering. As we are at home, we can put on all the appliances when we're generating the most electricity (we are on a flat 24hr rate)I buy electrictity at 24.5c a unit and sell at 19.5c a unit

celtic_oz · 21-03-2026 09:16AM

https://www.boards.ie/discussion/comment/124327670#Comment_124327670

are u 3 phase?

JohnySwan · 21-03-2026 09:30AM

https://www.boards.ie/discussion/comment/124329073#Comment_124329073

No, single phase.

Edit:

Like Unkle, I live in a modest semi detached house. Just lucky with the roof and garden orientation, a little bit of creativity and you can squeeze in quite a few panels.

unkel · 21-03-2026 11:47AM

https://www.boards.ie/discussion/comment/124329092#Comment_124329092

Exactly. 12 of my 36 panels are pure north facing. In Ireland that still generates about 55% of the same panel south facing. Obviously a longer payback time, but with the super generous feed in tariff in Ireland it is quick enough.

For me I got the panels for free, the materials at trade prices and a local roofer put them up for me for €250 with my help and me hooking them up to my inverter. 12 panels of 390wp each, so 4680wp, generating 4680 * 55% = 2574kWh per year or €643.50. This string had fully paid for itself before the year was out and now keeps generating €643.50 per year, which is nearly half my total gas bill for the year. A north facing string!

tom1ie · 21-03-2026 01:32PM

This is all very interesting information.
Where do I start?
Can anyone recommend an installer that can supply the setup that is something like @unkel has or is that something I would have to put together myself?
Can I get a system that will still supply power if I get a grid outage? (Changeover switch or something?)

What are the most efficient types of PV panels to get?

Does every solar supplier install panels on south facing walls as I think the former might be an issue?

Again thanks for all the comments folks

unkel · 21-03-2026 01:56PM

https://www.boards.ie/discussion/comment/124329469#Comment_124329469

All those questions have been answered several times in this forum, even in recent months. Spend the rest of the weekend reading this forum and you will know!

soram · 21-03-2026 02:00PM

https://www.boards.ie/discussion/comment/124329273#Comment_124329273

How do those numbers really stack up Unkel. I'm not here to stir anything but am genuinely interested. I have 8kW of panels and a 6kW inverter. To date my battery was only 10kWh so I could not really do that much load shifting. I did export just shy of €800 last year whcih covered my main electricity and both our names are on the bill so there was no tax liability. I have to bother about that as my wife is an accountant and really won't do anything even remotely opening her up to Revenue. So are your figures fully tax compliant as you must be exporting a huge amount? You also say your North facing panels generate over 2.5kW but how can you utilise this if you already have another 24 more south facing? I have a few friends with solar who seem to think everything is free but when you dig down they have a wood burning stove and supplement with other heat sources. I know you invest a huge amount of time in your systems but realistically you are a total outlier. I also invest some time but cannot reconcile the numbers in my house. I feel my neighbours are tapping in to me :)

unkel · 21-03-2026 02:29PM

https://www.boards.ie/discussion/comment/124329544#Comment_124329544

Yes of course I am an outlier. I build batteries and off and on grid renewable systems as my main hobby 😂

As for tax compliance - the feed in tariff has an income tax threshold of €400. Per person contributing to the bill. 5 of us in the family, all 5 contribute to the bill, so €2000 tax free income from feeding back

And yes to make serious money from feeding in, you will need a big battery and as much solar PV as you can fit. A standard compliant 5.5kW inverter is fine

So you can do what I do and have zero bills, fully legally and fully per all regs and your NC6 restrictions and without any tax liability

And your wife is quite right. You need to carefully do the sums to see if any investment in renewables has an acceptable pay back period for you. Which isn't easy as the systems change all the time. None of us were expecting a few years ago that you would be paid €0.25 per kWh feeding back to the grid. But as soon as we got that, I jumped onto it and have made thousands in profit because of it. If the system changes tomorrow to a fully dynamic tariff, I am ready, would just have to spend a few hours with Claude re-doing all my automations

soram · 21-03-2026 04:14PM

I still find it interesting they let ‘loads’ of people on the bill - happy days 😁

I’ve just put another 15kwh of Nkon in and will need a strategy for maximum return. We are only 2 so only have €800 tax free at the moment. Maybe even paying the tax is better than not earning.

I have a Solis and the ha automation for inverter control was ropey a few years ago and kept crashing my data logger so I turned it off. I’ll have to have another look! Might even try to get a second WiFi-s3 and flash it for local control!

Lots to let ‘Claude’ work out!

unkel · 21-03-2026 05:04PM

https://www.boards.ie/discussion/comment/124330016#Comment_124330016

We're getting flexible rates this year too, that is where a large battery can make lots of money. For the next few years the rates will not be great, but the more renewables we get on the national grid, the higher the arbitrage (=profit for battery owners)

Jo Satan · 22-03-2026 02:57PM

https://www.boards.ie/discussion/comment/124329469#Comment_124329469

Start by figuring out how many panels will fit on your roof and how much power they produce in a year.
I used Pylon - #1 Solar Design Software. You will probably sell 80% of this at up to 25c per kwh.

Then look at the solar quotes Domestic Solar PV Quotes thread and find quotes for solar panels and inverters, not batteries do not get your battery from an installer. Get some quotes yourself, post in the thread for confirmation. I would insist on a Solis inverter, can be used with most batteries, they are decent quality, have ok software, decent support and have a lot of users on this forum.

If you have a smart meter register with Home | ESB Networks, look at your daily usage. If you are considering a heat pump you will need to factor that in. You can use a website like Electricity Price Comparison to upload your usage and simulate adding solar, a battery, a heat pump and an EV.

Your battery size should cover your highest daily usage.

Look at the Solar PV battery options thread, decide if you want to build a battery or buy an off the shelf, the savings from DIY are not as big as they once were. Solar Home Battery - Lithium Solar Storage | Docan Power

Consider getting a heat pump, by going all electric you will get rid of the gas standing charge.
There are mid to high temperature heat pumps available now which can run at temperatures similar to gas whilst still operating at 300% to 400% efficiency. High Temperature Heat Pumps
With higher flow temps you may not need to replace radiators.
The grant is now up to €12500
The key to heat pumps is a proper heat loss survey and calculations including a blower door test. I would try to find an independent heat pump designer/ energy engineer not a salesman.

If you are a typical gas user ie 11,000 kwh your bill would be 11,000 x 8.35 cent= €918.50 + €139.72 standing charge
€1,058.22 before vat and levies.
A heat pump with a seasonal COP of just 3 will cost just €201 for 11,000 kwh if powered by a battery that was charged at an EV tariff of 5.5 cent.

You will have to bear in mind that there are restrictions on how much you can charge in an EV tariff window (typically 3 or 4 hours) as most inverters are restricted to 5kwh per hour, but there are ways around this discussed in this forum.

As to an EV, that's dependant on your weekly mileage and what influences your car purchases.

I went the whole hog and over the last two years have acquired solar, a DIY battery, a second hand EV and an A2 home with a heat pump.
I have no power or fuel bills and €700 credit over the year. My bills would have been around €5k annually for house and car.
Its a significant outlay and learning curve, but the payback period for me is about 4 years.