Domestic Solar PV: "Eco Bling" or does 10+ year payback make sense?

PGL · 25-03-2021 11:31am #1

Hi folks

Apologies if this question has been asked before, but I couldn't find it.

I am interested in getting a solar pv system installed in my home (typical 4-bed semi d). I am very much pro renewable energy in general, so I really want to get it installed. However I'm struggling to get my head around whether it makes financial sense at this point.

To date, I have only received one quote (won't name the company) of €8,600 including VAT and inclusive of the grant for a 4.125kWp system (11 x 375W panels) with a dual string hybrid inverter, 1 x 2.4kWh battery and an Eddi power diverter to heat my hot water cylinder. Based on my typical pre COVID annual electricity usage of 5,800kWh, the company in question are suggesting it will take just under 10 years for the system to pay for itself. If the battery is excluded, I'm told the price drops to €6,000, and the pay back period increases to 10-12 years.

Looking at SEAI's website, it appears that a 10 year pay back period is the norm at present.

Taking all of this on board, my initial thoughts are that if money is not an object, you don't hesitate and get onboard with renewable energy like domestic solar PV. However, for the average household (including myself) in this country, does a pay back period of roughly 10 years make sense? Taking the estate (constructed in 1997) that I live in as an example there are only 2 or 3 houses out of a total of 90 that have solar PV installed, and anecdotally looking further afield, it appears that apart from new houses, there is a very low uptake of solar PV - this would suggest it doesn't yet make financial sense.

The company that quoted me are of the view that SEAI will stop providing grants in the next few months once homes start getting paid for the unused solar energy that they export to the grid. Do you guys agree? I would have thought if the government are really serious about decarbonisation, they need to keep grants in place at the very least and also considering increasing them.

Interested to hear peoples thoughts on all of this in general and as to whether domestic solar PV is currently "eco bling" for the wealthy, is a 10 year payback reasonable, and whats the likelihood of costs reducing?

Thanks!

Ubbquittious · 25-03-2021 11:48am

You get around 1KWh per Wp in this country. Maybe some lads are getting a bit more or a bit less

At 20c/KWh if you manage to use all the electricity yourself without donating to the grid or exporting at a paltry rate you're bringing in 825 quid a year. So without the battery you could break even before 10 years as long as you're a heavy enough user of electricity in the summer during the day.

There's a lot of eco-bling out there and it's easy to get sucked in if you spend a lot of time reading this forum and drinking the kool-aid. If you really want quick payback you'll have to run a clapped out system where you do all the donkey work yourself and eschew the fancy options. You can sit back with your PV installation and let it pay for itself but the real serious eco-bling territory is where you start buying 2 brand new EV's and paying some fella 20k to put in a heat pump. There's huge costs involved with going down that road and usually justified by "doing the right thing for the planet" but the sunk costs are just too vast to be recouped in any reasonable timeframe. There's other investments where you could get a much higher yield for your money

I will hopefully be putting in about 3KWp soon and should cost less than 2k. Secondhand inverter and doing the wiring myself. If the inverter doesn't pack up should be paid back in about 4 years. If it does pack up there is a chance I'll be able to repair it, otherwise add another year for it to pay for itself

mp3guy · 25-03-2021 11:54am

PGL wrote: »

I am very much pro renewable energy in general, so I really want to get it installed. However I'm struggling to get my head around whether it makes financial sense at this point.

I think you need to be honest with yourself, are you really pro renewable? It sounds like money matters more to you right now than your carbon footprint. I'm sure you like the idea of going eco but not if it hits your wallet too much. Which is fair enough.

PGL wrote: »

Taking all of this on board, my initial thoughts are that if money is not an object, you don't hesitate and get onboard with renewable energy like domestic solar PV. However, for the average household (including myself) in this country, does a pay back period of roughly 10 years make sense? Taking the estate (constructed in 1997) that I live in as an example there are only 2 or 3 houses out of a total of 90 that have solar PV installed, and anecdotally looking further afield, it appears that apart from new houses, there is a very low uptake of solar PV - this would suggest it doesn't yet make financial sense.

It suggests most people aren't willing to accept the financial hit it will take to bring down their CO2 output. If it was financially better to go green, climate change wouldn't be an issue today.

Not trying to be critical of you, guilt you into anything or suggest you sell your cars and cycle everywhere. Maybe you're happier spending that money on something else and waiting on the grid to decarbonise itself.

If you want to you can hussle and DIY it and lock in a payback in 5-7 years if you really want to, but if you want it to be easy, you need to accept that the investment might not pay itself off in reasonable time (how many investments can you make that will though? it's all a risk, except with PV you can write down the tonnes of CO2 saved over the years). Spend that money on an extension, new car, five star holiday, you get different returns.

slave1 · 25-03-2021 12:37pm

PGL wrote: »

Hi folks

Apologies if this question has been asked before, but I couldn't find it.

I am interested in getting a solar pv system installed in my home (typical 4-bed semi d). I am very much pro renewable energy in general, so I really want to get it installed. However I'm struggling to get my head around whether it makes financial sense at this point.

To date, I have only received one quote (won't name the company) of €8,600 including VAT and inclusive of the grant for a 4.125kWp system (11 x 375W panels) with a dual string hybrid inverter, 1 x 2.4kWh battery and an Eddi power diverter to heat my hot water cylinder. Based on my typical pre COVID annual electricity usage of 5,800kWh, the company in question are suggesting it will take just under 10 years for the system to pay for itself. If the battery is excluded, I'm told the price drops to €6,000, and the pay back period increases to 10-12 years.

Looking at SEAI's website, it appears that a 10 year pay back period is the norm at present.

Taking all of this on board, my initial thoughts are that if money is not an object, you don't hesitate and get onboard with renewable energy like domestic solar PV. However, for the average household (including myself) in this country, does a pay back period of roughly 10 years make sense? Taking the estate (constructed in 1997) that I live in as an example there are only 2 or 3 houses out of a total of 90 that have solar PV installed, and anecdotally looking further afield, it appears that apart from new houses, there is a very low uptake of solar PV - this would suggest it doesn't yet make financial sense.

The company that quoted me are of the view that SEAI will stop providing grants in the next few months once homes start getting paid for the unused solar energy that they export to the grid. Do you guys agree? I would have thought if the government are really serious about decarbonisation, they need to keep grants in place at the very least and also considering increasing them.

Interested to hear peoples thoughts on all of this in general and as to whether domestic solar PV is currently "eco bling" for the wealthy, is a 10 year payback reasonable, and whats the likelihood of costs reducing?

Thanks!

Sorry for this angle of "attack" but take it in the spirit it's meant.

Firstly your quote is mad high, get more as you are around €3k too high when looking at installs the likes of DrPhil and myself have had installed.
Imagine what a €3k less Capital Investment will do to your payback!!

Your savings need to be based on the cheapest day/night rate rate out there.
I'm with Energia and paying 14.22c day/6.82c night, let's say a weighted average of 9.78c a unit for simplicity purposes.

IF and it's a big IF you generate 4.125kWh a year and IF (and this is probably a bigger IF) you consume 100% of it (there are losses left right and centre with PV cabling and diversion) then you will have saved €403 a year.
It is reasonably safe to say you will not generate 4.125kWh and you will not consume 100% of it.
Okay, we can throw some Feed In Tariff into it and maybe you charging the battery at night over Winter but remember a 2.2kWh supply will last just about a modern washing machine cycle and then depleted.
Let's therefore assume that the FIT and battery usage in Winter washes out the earlier comment re generation/self consumption/losses.

So, a Capital Investment of say, €5.6k, a (very generous) saving of €403 a year and you are looking at a simple Payback of 14 years.

Remember at some stage the inverter/diverter will pop it's clogs and the battery efficiency will drop off, this will require re-investment and further Payback.
Yes I realise electricity prices will increase over time but that's a load of horsesh1t, I change ever year and never pay more than previous year.

Hope this helps.
Advice here will probably be ditch the battery option which will lower your initial cost (and cost of inverter which would be my concern as that's an expensive replacement).

If you are doing it be sure to run loads of ethernet cables for future proofing install of an EV charge point.

PGL · 25-03-2021 2:01pm

Great honest feedback so far folks - keep it coming!

It may not have sounded like it, but i am genuinely in favour of renewable generation, and probably will have to accept a long pay back period. But costs are clearly going to have to come down to get buy in from the majority of society.

I will definitely get a few more quotes and am glad to hear my first quote is on the high side. I am starting to sway away from getting a battery, but will need to see a few more quotes first.

BTW: I am not in a position to do a DIY job, use second hand equipment etc

slave1 · 25-03-2021 3:42pm

PGL wrote: »

... But costs are clearly going to have to come down to get buy in from the majority of society...

Can't see it happening, panels and inverters are as cheap as ever, have a look at YouTube and see the full costs from other countries, we are doing very well on costs.
The inverter is the single biggest equipment outlay and you can get a 4.6kWh Solis for your system for less than €600 ex VAT, can't see prices coming down much more than that...

KCross · 25-03-2021 7:25pm

PGL wrote: »

To date, I have only received one quote (won't name the company) of €8,600 including VAT and inclusive of the grant for a 4.125kWp system (11 x 375W panels) with a dual string hybrid inverter, 1 x 2.4kWh battery and an Eddi power diverter to heat my hot water cylinder.

Ditch the hybrid inverter for a standard 5kW+ one.
Ditch the battery and the eddi also, they just increase the cost now, and in the future when they need to be replaced, and they will need to be replaced.

Get a quote of ~€4500 (after grant) for a 4-5kWp system and then pull the trigger!

ec_pc · 25-03-2021 9:24pm

The other factors include inflation in electricity costs, what will the unit cost be in in 5 years time? What about FIT rates too? I suspect as time passes and unit rates increase, then we will really see a return on investment, besides being nice to the environment of course.

farmerval · 25-03-2021 9:38pm

The OP is looking at a battery in his system. Without one how many people will get to use the power they are generating?

Lots of people are at work when power is being generated, so little opportunity to use the power, timers for washing machine etc fair enough, but will more thaN 5O% of what you generate be used?

KCross · 25-03-2021 9:46pm

ec_pc wrote: »

The other factors include inflation in electricity costs, what will the unit cost be in in 5 years time? What about FIT rates too? I suspect as time passes and unit rates increase, then we will really see a return on investment, besides being nice to the environment of course.

The unit price hasnt changed much for me over the last 10 years. Change each year and get the best deals.

farmerval wrote: »

The OP is looking at a battery in his system. Without one how many people will get to use the power they are generating?

Lots of people are at work when power is being generated, so little opportunity to use the power, timers for washing machine etc fair enough, but will more thaN 5O% of what you generate be used?

No need to have a battery when there is a Feed-in-tariff on the way. The grid is your battery.

slave1 · 25-03-2021 10:07pm

KCross wrote: »

N need to have a battery when there is a Feed-in-tariff on the way. The grid is your battery.

..and in a few years so will your EV

mp3guy · 25-03-2021 10:22pm

slave1 wrote: »

..and in a few years so will your EV

Gotta factor in the cost of an EV that can do this though!

slave1 · 25-03-2021 11:16pm

It’s like the tide at this stage, no avoiding

Alkers · 26-03-2021 12:31am

Is there someone going to be home during the day long term?
IMO the best system interns of payback is a small 2.5-3kW array without a battery or hybrid inverter. Can be had for less than 2,500e after the grand and can be paid over ten years, so depending on your usage, you could see cashflow positive summer months off the bat

Patmwgs · 26-03-2021 9:14am

PGL wrote: »

Hi folks

Apologies if this question has been asked before, but I couldn't find it.

I am interested in getting a solar pv system installed in my home (typical 4-bed semi d). I am very much pro renewable energy in general, so I really want to get it installed. However I'm struggling to get my head around whether it makes financial sense at this point.

To date, I have only received one quote (won't name the company) of €8,600 including VAT and inclusive of the grant for a 4.125kWp system (11 x 375W panels) with a dual string hybrid inverter, 1 x 2.4kWh battery and an Eddi power diverter to heat my hot water cylinder. Based on my typical pre COVID annual electricity usage of 5,800kWh, the company in question are suggesting it will take just under 10 years for the system to pay for itself. If the battery is excluded, I'm told the price drops to €6,000, and the pay back period increases to 10-12 years.

Looking at SEAI's website, it appears that a 10 year pay back period is the norm at present.

Taking all of this on board, my initial thoughts are that if money is not an object, you don't hesitate and get onboard with renewable energy like domestic solar PV. However, for the average household (including myself) in this country, does a pay back period of roughly 10 years make sense? Taking the estate (constructed in 1997) that I live in as an example there are only 2 or 3 houses out of a total of 90 that have solar PV installed, and anecdotally looking further afield, it appears that apart from new houses, there is a very low uptake of solar PV - this would suggest it doesn't yet make financial sense.

The company that quoted me are of the view that SEAI will stop providing grants in the next few months once homes start getting paid for the unused solar energy that they export to the grid. Do you guys agree? I would have thought if the government are really serious about decarbonisation, they need to keep grants in place at the very least and also considering increasing them.

Interested to hear peoples thoughts on all of this in general and as to whether domestic solar PV is currently "eco bling" for the wealthy, is a 10 year payback reasonable, and whats the likelihood of costs reducing?

Thanks!

If you are serious about going green , then get a few more quotes and go for it. Ditch all the fancy stuff as repeated here already. Cheaper options than the eddi. If someone is home during the day then ditch the batteries also. Depreciation on these is fairly high. Invest in an ev eventually, (big outlay). They really need to encourage change in buying ev,s. I went green about 14 years ago and ver happy that i did. No grants back then and planning permission had to be paid for also. I would love to invest in an ev now, but but dont like pcp.
Go for it and enjoy it.

PGL · 26-03-2021 10:08am

KCross wrote: »

Ditch the hybrid inverter for a standard 5kW+ one.

For my ignorance what is the difference between hybrid and standard inverters, and does anyone know why the company may have specified one?

Edit: The company are proposing two strings because they are proposing adding a few panels on the roof of a single story extension to the rear of the house. Would the need for two strings drive the need for a hybrid inverter?

KCross wrote: »

Ditch the battery and the eddi also, they just increase the cost now, and in the future when they need to be replaced, and they will need to be replaced.

I'm neutral on a battery and would be open to getting one if it makes sense, but I want a power divert to heat my hot water cylinder. Are you suggesting there is no need for a power diverter, or are you saying I should opt for a cheaper power diverter than an Eddi?

KCross wrote: »

Get a quote of ~€4500 (after grant) for a 4-5kWp system and then pull the trigger!

I presume this quote would exclude a battery and power diverter and therefore just the solar panels and a standard inverter?

PGL · 26-03-2021 10:11am

Alkers wrote: »

Is there someone going to be home during the day long term?

I have been working from home for the past 12 months now, while the wife and 3 kids are at school. However in the long term there generally won't be anyone home during the day for the next 15 to 20 years

unkel · 26-03-2021 10:17am

Patmwgs wrote: »

Invest in an ev eventually, (big outlay).

It doesn't have to be a big outlay at all

You can buy a Nissan Leaf from 2011/2012 from about €3k and you get a €600 subsidy to install a home charge point, which should make it free for a basic install if you pick up a second hand charge point

This will be an ideal short range second family car, with a lower total cost of ownership than a €500 petrol / diesel banger as the maintenance and fuel costs almost nothing and depreciation is almost non existent as the battery itself will still be worth €1500 even if you write the car off / is end of life

Patmwgs · 26-03-2021 11:40am

PGL wrote: »

For my ignorance what is the difference between hybrid and standard inverters, and does anyone know why the company may have specified one?

Edit: The company are proposing two strings because they are proposing adding a few panels on the roof of a single story extension to the rear of the house. Would the need for two strings drive the need for a hybrid inverter?

I'm neutral on a battery and would be open to getting one if it makes sense, but I want a power divert to heat my hot water cylinder. Are you suggesting there is no need for a power diverter, or are you saying I should opt for a cheaper power diverter than an Eddi?

I presume this quote would exclude a battery and power diverter and therefore just the solar panels and a standard inverter?

If you are just using a power diverter for hot water you will get on for a third of the price of an eddie. I would suggest you get a bigger hot water tank also , if you haven't one.

Patmwgs · 26-03-2021 11:42am

unkel wrote: »

It doesn't have to be a big outlay at all

You can buy a Nissan Leaf from 2011/2012 from about €3k and you get a €600 subsidy to install a home charge point, which should make it free for a basic install if you pick up a second hand charge point

This will be an ideal short range second family car, with a lower total cost of ownership than a €500 petrol / diesel banger as the maintenance and fuel costs almost nothing and depreciation is almost non existent as the battery itself will still be worth €1500 even if you write the car off / is end of life

Thanks, i will keep looking. At that age of car i would be worried about the battery condition.
I am lucky in a way as i could charge at night.

Alkers · 26-03-2021 12:42pm

PGL wrote: »

I have been working from home for the past 12 months now, while the wife and 3 kids are at school. However in the long term there generally won't be anyone home during the day for the next 15 to 20 years

This is your single biggest obstacle in terms of payback, you aren't at home to avail of the power generated. FIT will determine the financial viability for you.

Patmwgs · 26-03-2021 1:13pm

Alkers wrote: »

This is your single biggest obstacle in terms of payback, you aren't at home to avail of the power generated. FIT will determine the financial viability for you.[/QUOTE
The original micro generation payment made an enormous difference to my payback. Unfortunately wont be be anywhere as good as it was. You need to self consume as much as possible.

Ubbquittious · 26-03-2021 1:58pm

Patmwgs wrote: »

Thanks, i will keep looking. At that age of car i would be worried about the battery condition.
I am lucky in a way as i could charge at night.

When you start taking a gamble on some 10 year old electric car in order to break even you're headed down a slippery slope. Maybe if you're prepared to do your own repair work on it you can make it pay. You have to tax and insure and NCT the thing and this already costs more than what power you'd generate in a year

I'd be inclined to find a cheaper way of using up the excess power. Come up with some heavy load that you can swithc on remotely if it's sunny or a couple of them

slave1 · 26-03-2021 2:07pm

Ubbquittious wrote: »

I'd be inclined to find a cheaper way of using up the excess power.

FIT

Patmwgs · 26-03-2021 3:30pm

Ubbquittious wrote: »

When you start taking a gamble on some 10 year old electric car in order to break even you're headed down a slippery slope. Maybe if you're prepared to do your own repair work on it you can make it pay. You have to tax and insure and NCT the thing and this already costs more than what power you'd generate in a year

I'd be inclined to find a cheaper way of using up the excess power. Come up with some heavy load that you can swithc on remotely if it's sunny or a couple of them

Its wind i need, which seems to be very plentiful on the donegal coast.

Ubbquittious · 26-03-2021 4:00pm

Patmwgs wrote: »

Its wind i need, which seems to be very plentiful on the donegal coast.

I was looking at a TESUP turbine not so long ago, wonder are they any good

Lots of people have problems with small turbines though anyone I know who has one has had trouble. Where about in Donegal are you? far inland?

slave1 · 26-03-2021 4:12pm

Decent wind turbines cost multiple the cost of equivalent solar panels, if this thread is say 14years payback as a example then surely multiple of that for wind payback and that payback would be eliminated if turbine needs to be replaced whereas panels last 20/30yrs

Patmwgs · 26-03-2021 4:58pm

slave1 wrote: »

Decent wind turbines cost multiple the cost of equivalent solar panels, if this thread is say 14years payback as a example then surely multiple of that for wind payback and that payback would be eliminated if turbine needs to be replaced whereas panels last 20/30yrs

Up to a month ago my turbine has produced 1151061kwh in 97498 hours and with the 19 cent
Micro generation scheme it brought payback well down. Self install 6kw on 15m tower. It cancelled out our yearly electric use. We were almost always in credit. You do need to service it every 2 years to keep it running smoothly. The beaty of pv is very little up keep. Lifespan of turbine is quoted for 25years. Its coastal rated.

Patmwgs · 26-03-2021 5:05pm

Ubbquittious wrote: »

I was looking at a TESUP turbine not so long ago, wonder are they any good

Lots of people have problems with small turbines though anyone I know who has one has had trouble. Where about in Donegal are you? far inland?

I dont know tesup turbine, i will look it up. Alot of small wind turbine are very problematic and if you dont service them yourself it will be costly. South donegalabout 3 kms inland.

KCross · 26-03-2021 7:05pm

PGL wrote: »

For my ignorance what is the difference between hybrid and standard inverters, and does anyone know why the company may have specified one?

Hybrid is required for batteries. Significantly increases the cost of the inverter to get a hybrid. Some might say get hybrid to future proof for batteries but thats just mad, imo, the grid is your battery... FiT is where its at.

If you decide to go battery later you can always sell your standard one and get hybrid in after. No sense to do it up front with FiT on the way.

PGL wrote: »

Edit: The company are proposing two strings because they are proposing adding a few panels on the roof of a single story extension to the rear of the house. Would the need for two strings drive the need for a hybrid inverter?

As above, standard inverters will support dual string also.

PGL wrote: »

I'm neutral on a battery and would be open to getting one if it makes sense, but I want a power divert to heat my hot water cylinder. Are you suggesting there is no need for a power diverter, or are you saying I should opt for a cheaper power diverter than an Eddi?

I'm saying if you want to reduce the time for your ROI then get a simpler system that will be cheaper to buy and maintain/replace and then maximise self-consumption. The replacement costs on the battery and hybrid inverter after 10-15 years will be significant in terms fo payback/ROI.

If you can get a cheper diverter then by all means get that but just bear in mind that the diverter will take a long time to pay for itself unless you are currently heating your water by immersion or some other expensive method.

If you already have cheap hot water (e.g. heat pump on night rate) the diverter would literally never pay for itself so dont assume that its a good investment. Do the math.

Finally, with FiT on the way you would need to consider would you be better off getting the FiT payment or dumping the excess into a diverter. The FiT payment is likely to be a better option since there is no capital outlay on that... you just export and get paid. The diverter you have to buy/maintain/replace.

PGL wrote: »

I presume this quote would exclude a battery and power diverter and therefore just the solar panels and a standard inverter?

Yes.

DrPhilG · 26-03-2021 9:31pm

PGL wrote: »

To date, I have only received one quote (won't name the company) of €8,600 including VAT and inclusive of the grant for a 4.125kWp system (11 x 375W panels) with a dual string hybrid inverter, 1 x 2.4kWh battery and an Eddi power diverter

If the battery is excluded, I'm told the price drops to €6,000

Have you a breakdown of that quote?

I'm not sure how he's dropping the price by €2,600 by removing a battery that (minus grant) should be costing you no more than €5-600 unless I'm missing something?

You didn't specify, but maybe on the no battery option he's changing the hybrid for a standard inverter which would be another maybe €6-700 difference.

I'd be very keen to see the breakdowns if you have them.

Either way it's too expensive. I paid a lot less than your higher price for a lot more kit. 6.2kwp with 5kw hybrid, 2.4kWh storage and a new Zappi 2 charger (replacing an older install in fairness).

PGL · 29-03-2021 10:45am

DrPhilG wrote: »

Have you a breakdown of that quote?

I'm not sure how he's dropping the price by €2,600 by removing a battery that (minus grant) should be costing you no more than €5-600 unless I'm missing something?

You didn't specify, but maybe on the no battery option he's changing the hybrid for a standard inverter which would be another maybe €6-700 difference.

I'd be very keen to see the breakdowns if you have them.

Either way it's too expensive. I paid a lot less than your higher price for a lot more kit. 6.2kwp with 5kw hybrid, 2.4kWh storage and a new Zappi 2 charger (replacing an older install in fairness).

I didn't receive a breakdown, but will request it, and am also chasing down a couple more quotes.

Do you mind me asking how much you roughly paid for your system?

DrPhilG · 29-03-2021 11:05am

PGL wrote: »

I didn't receive a breakdown, but will request it, and am also chasing down a couple more quotes.

Do you mind me asking how much you roughly paid for your system?

€6.7k was the first quote I think, that was 20 panels, 5kw hybrid inverter, iBoost diverter (I later changed to an Eddi), myenergi hub, Zappi 2 charger, monitoring/app etc.

PGL · 29-03-2021 11:07am

KCross wrote: »

I'm saying if you want to reduce the time for your ROI then get a simpler system that will be cheaper to buy and maintain/replace and then maximise self-consumption. The replacement costs on the battery and hybrid inverter after 10-15 years will be significant in terms fo payback/ROI.

If you can get a cheper diverter then by all means get that but just bear in mind that the diverter will take a long time to pay for itself unless you are currently heating your water by immersion or some other expensive method.

If you already have cheap hot water (e.g. heat pump on night rate) the diverter would literally never pay for itself so dont assume that its a good investment. Do the math.

Finally, with FiT on the way you would need to consider would you be better off getting the FiT payment or dumping the excess into a diverter. The FiT payment is likely to be a better option since there is no capital outlay on that... you just export and get paid. The diverter you have to buy/maintain/replace.

My existing hot water cylinder is currently heated by both my gas boiler and the immersion heater. Its not a large cylinder (100L i'd say), and the amount of hot water tends to get used up quickly enough (2 adults and 3 small kids), so I think I probably need a larger cylinder regardless of whether or not I get solar panels and a power diverter. I have no idea how much it costs to heat it at present, but do people think it will make more sense to export unused solar power versus heating the hot water cylinder first?

slave1 · 29-03-2021 11:49am

Hot water breaks the financial perspective for me as hot water is also convenient, with a house of women apart from me there is the hair washes and the amount of water used up, for us it is very convenient to just let the excess PV heat the water so if an evening hair wash or whatever requires hot water then it's there and I don't need to go upstairs and put on the immersion (no gas heating).
You will need to increase your cylinder to at least 300L as otherwise you will lose any benefit in investing in a hot water diverter.

Again, hot water diverters rarely make any financial sense, it's more convenience.
November through February will do sweet fanny adams in terms of heating water unless you have larger south facing array.

unkel · 29-03-2021 2:26pm

Heating hot water is only worth 5c / kWh, so it would take a long time to get your investment of €500, to get a diverter installed, back. If ever. And if we get a feed in tariff even if only a few cents, it's guaranteed never to pay for itself

irishchris · 29-03-2021 2:55pm

unkel wrote: »

Heating hot water is only worth 5c / kWh, so it would take a long time to get your investment of €500, to get a diverter installed, back. If ever. And if we get a feed in tariff even if only a few cents, it's guaranteed never to pay for itself

But again as slave says it's more about convenience. For me I have oil or pellet stove heating but from here to summer it is rarely on and find the eddi diverter priceless for convenience of having hot water on demand instead of herself or kids going for shower and then thinking oh crap forgot to turn on the oil earlier so wait a half hour for it to heat up.

Alkers · 29-03-2021 3:56pm

slave1 wrote: »

Hot water breaks the financial perspective for me as hot water is also convenient, with a house of women apart from me there is the hair washes and the amount of water used up, for us it is very convenient to just let the excess PV heat the water so if an evening hair wash or whatever requires hot water then it's there and I don't need to go upstairs and put on the immersion (no gas heating).
You will need to increase your cylinder to at least 300L as otherwise you will lose any benefit in investing in a hot water diverter.

Again, hot water diverters rarely make any financial sense, it's more convenience.
November through February will do sweet fanny adams in terms of heating water unless you have larger south facing array.

You still need to do the math. If you value the convenience, see how much it would cost to get a combi boiler instead of your current setup and have all the instant-access hot water you want, it could work out well cheaper than a new hot water tank PV diverter etc and not use up the surplus electricity that you'll be able to get a FIT (at some stage for).

slave1 · 29-03-2021 4:07pm

Alkers wrote: »

You still need to do the math. If you value the convenience, see how much it would cost to get a combi boiler instead of your current setup and have all the instant-access hot water you want, it could work out well cheaper than a new hot water tank PV diverter etc and not use up the surplus electricity that you'll be able to get a FIT (at some stage for).

No gas available and I'm not going the tank route given location of hot press.
The Diverter was self install so just the equipment cost, it was around €360 for an EDDI and then a couple of neon isolation switches.
Can't really place a value of convenience.

Patmwgs · 29-03-2021 4:30pm

I have installed a solic 200 wireless version , the convenience factor is big one for me as i produce lecci at night also. I used to switch on 3kw or 2kw or one kw immersion manually at night and hoped the wind kept up. I now have the diverter wired to bottom 3kw of a 500ltr tank and its fantastic. Would of got it ages ago but alot of early diverters had lots of teething trouble.

Alkers · 29-03-2021 6:05pm

slave1 wrote: »

No gas available and I'm not going the tank route given location of hot press.
The Diverter was self install so just the equipment cost, it was around €360 for an EDDI and then a couple of neon isolation switches.
Can't really place a value of convenience.

That's fair enough but quite specific to your particular situation. In general, PV diverter is not the best way to provide hot water.

KCross · 29-03-2021 9:19pm

irishchris wrote: »

But again as slave says it's more about convenience. For me I have oil or pellet stove heating but from here to summer it is rarely on and find the eddi diverter priceless for convenience of having hot water on demand instead of herself or kids going for shower and then thinking oh crap forgot to turn on the oil earlier so wait a half hour for it to heat up.

Unless you control the sun its not really on-demand though!

So you still have the exact same issue of potentially running out of water. It might happen less often but there will be days in the summer where it will give you zilch so you cant rely on it at any time really.

Instead of spending it on a diverter spend it on a few extra panels and have money coming in for FiT. But I understand its a case of each to their own on this one just as long as you do it with your eyes open and not thinking that you are saving money by putting in a diverter... thats the main point.

Patmwgs · 29-03-2021 9:56pm

KCross wrote: »

Unless you control the sun its not really on-demand though!

So you still have the exact same issue of potentially running out of water. It might happen less often but there will be days in the summer where it will give you zilch so you cant rely on it at any time really.

Instead of spending it on a diverter spend it on a few extra panels and have money coming in for FiT. But I understand its a case of each to their own on this one just as long as you do it with your eyes open and not thinking that you are saving money by putting in a diverter... thats the main point.

You are right of course about making back the price of anything you add to the system.
I just have the mrs to talk to. I dont have eddie that talks to zappi who in turn talks to harvi, or is it the other way round. I would love these gadgets too one day.

Manic Moran · 31-03-2021 11:06pm

Really it depends on how long you're planning on owning the house.

In my case, electricity from the grid here is dirt cheap, I don't think I'm going to get it 'paid back', as it were, until about 32-33 years. That's on the basis of whatever the current rates are for kWh. If base electricity prices go up, then I'll make it back a bit sooner. Regardless, it is still, for me, purely an economical decision, and a peace of mind decision. Much though I don't mind helping the planet, that is purely under the category of 'beneficial side effect.' I got an install, not which covers my full usage, but which covers my typical usage, and I'll still buy from the grid for the few months where my usage exceeds generating capacity.

In 30 years time, when I'm retired and on my pension and life savings, electricity bills will be one less thing I need to worry about, I'll have the majority of it on the roof. Even if I do end up selling the house, the value increase of the house ought to cover the vast majority of the cost of the installation.

I do not expect to make any meaningful money from exporting to the grid. I don't know how FiT will work for you guys, but here we are paid "wholesale" prices for kWh, which is about a quarter of what is billed to the final user (This is separate to net metering, which is a 1-for-1 deal). I'll be happy if my exports cover the connection fee.

The financial question is "If I took that money, and the interest I'm paying on the payments, and instead invested some and spent the rest on the electricity bills, would I be better off with solar or no?" It's difficult to say, as solar will continue to get cheaper. I might be better off investing for five years, then spending the next 25 on a solar install which because the panels were cheaper to make, cost only half as much (Or whatever). You need to make a judgement call and a gamble.

In my case, I decided that the costs I knew (i.e. cost of solar install) were acceptable, no matter what the alternatives may have been with the aid of a crystal ball. I'm not planning on leaving this house, I like having a fixed cost for most of my power needs and being immune to rate changes. And I like having 2/3 of my electricity for free in retirement. So if I can consider 30 years to be a financially sensible move, 10 years for you may not be too bad....

garbanzo · 11-05-2022 9:04pm

https://www.boards.ie/discussion/comment/116691919#Comment_116691919

Just to say that’s exactly what I’ve done. Deposit paid. Install in June.

Will report back.

g

spose · 12-05-2022 3:43pm

For those of us on oil it’s not 5c a kWh to heat that water either more like 15c at the moment.

bullit_dodger · 12-05-2022 4:37pm

Good call spose! I was curious to get a more exact price. I include the below to anyone else interested ......

So average price is €1.42/liter for heating oil in Ireland at the moment.

Heating Oil Prices in Ireland (1000 Litres) - Oil Prices Ireland

1 Liter of heating oil has ~10.3khr of energy. Putting it at €0.137 / Kwhr (kerosene). Then factor in some losses as a boiler isn't 100% efficient, as opposed to your immersion which typically is like 98-99% efficient. Let's call the boiler 85% efficient. Therefore heating water from a kerosene boiler would be...

€0.137 * 1.15 = €0.157

Cheaper to heat your water on night rate and then "top up" if needed the heat during the day

loyatemu · 12-05-2022 8:40pm

I'm on gas and I'd generally use 60% as the efficiency for comparing hot water heating - even if your boiler is 80% efficient (which is generally a best case scenario when it's running at full heat) we've long pipe runs to the HW tank which reduces that further. Having said that, I don't think we're spending more than a euro a day on hot water even at current gas prices.

The big problem with solar from the payback perspective is that you get the most power in the summer when you use the least. We're usually away for 3 weeks over the summer months, that's 5% of the year at the time of maximum production when we wouldn't be able to use any of it. Also last time I looked at the "smart" tariffs required to sell back to the grid, they were terrible value, custom designed to more than cancel out any money you make from feed-in unless you're prepared to do all your washing and cooking at 3am on a Sunday morning (might be a different calculation if you have an EV though),.

bullit_dodger · 13-05-2022 12:15am

Condenser boilers typically are pretty good on gas. ~90% or so. If you haven't had one cleaned for a bit probably 80-85%. But that's a good point, I used 85%, but an oil boiler is probably lower. Maybe in the 70's. Either way, even giving it the benefit of the doubt.....night rate leccie is now about 20-30% cheaper than oil anyway. Kinda crazy how much oil has gone up.

steamdave · 19-06-2022 2:16pm

I'm pretty new to this Solar PV thing and been reading through the various posts about it. I've even progressed to getting a few quotes and have decided to go ahead with installing a system.

This thread started last year and it appeared to some like it was touch and go whether it was worth putting up a system because of the possible 10 year payback. How times have changed.

There are 44 posts on this subject on 2 pages, but look at the PV Quotes thread and there are 2545 posts over 85 pages!

Instead of 'eco-bling' last year, it is full steam ahead to get a system quoted for and installed this year. The rocketing costs of electricity have certainly changed folks' perspective on whether a Solar PV system is a desirable asset. So the 10 year pay-back time has come down to about 8.5 years or thereabouts, depending on the system size and parts making it more desirable.

I believe the FIT is a red herring and maybe there will be some reward but the electricity companies are sure going to do their utmost to get their payout back or at least make it not worthwhile considering.

Let's see which camp is right in the long run. I guess it will be the folk who get a system installed sooner rather than later who will benefit compared to the 'eco-bling' believers.

Dave

THE ALM · 20-06-2022 10:34am

Certainly glad we had our installed last year and it seems like fortuitous timing that we did.

Several family and friends are currently waiting on installs and prices have certainly crept up even though ours only went live at the beginning of December.

I'll be interested to see after the first year how things are playing out but we are expecting considerable enough savings taking into account the the pv is currently powering the house, heating the water and fuelling the car.

We are not flush with money but it is an investment we are glad to have made and one that adds to the houses value should we look to sell. I think people buying a house look at all these 'extras' and makes a house a more attractive proposition with them and will pay a premium for well installed systems.

Domestic Solar PV: "Eco Bling" or does 10+ year payback make sense?

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