Pompeyexile can afford, trying to get the best value for my money knowing that if for example I go for a combi boiler, I will hopefully get a good ten years out of it before it needs replacing. It costs me what it costs. I never think about payback, so why would I think about that if installing solar or an air source heat pump? If that is the type of heating I go for and it costs 5, 8 or 15 grand it is what it is, and as long as it does its job and lasts long enough then great. The only return I expect is for it to work for a number of years

The issue is specific and slightly different for all situations, plus much of the information on the Internet is misleading or way out of date, and the conclusions based on out of date information.

  • The various incentives have changed
  • FIT tariffs have changed and amounts can be very small, so it’s more important to use what you produce
  • Prices have not come down rather the reverse..the headline prices you see are never what you get quoted
  • Inverters don’t last as long as you think and are not factored into TCO
  • Panels degrade (life expectancy is around 30 years
  • Panels have to be cleaned or efficiency drops
  • The amount of power is often overestimated
  • You don’t get much power at all in winter

So when I asked for a quote for 3 kW or so on my Garage, perhaps 4 if I could get really high quality panels and a battery, it came to 23K….a ludicrous price. However lets take this system…apparently only from £13454..now we know it’s going to end up more, but lets pretend that it doesn’t rise.

https://worldofsolar.com/package-1/

I use about 8kW per day, sometimes 7…that costs me at the moment 34.5p per kW inc VAT, prices may not go up and I think long term they might well drop as I am not sure this is sustainable. Electric costs me around £82 per month. I won’t save on standing charge or anything like that.

Lets pretend my house roof faces the perfect direction and I get 80% (4.8kw) of generation for 6 hours a day)…that’s 28Kw per day on perfect days and lets say we get 75% of those for the summer May to Aug…5 months. April and Sep, perhaps we get an average of 6kW per day, and the other 6 months not that much, lets call it 1kW per day every day. The feed in tariff is usually around 5p but I have seen higher prices quoted by sites that sell solar power…..so lets go with a 10p payment for every unit you export…unlikely, but lets do it.

  • Summer months no electric costs and £1.50 per day (deducted electric standing charge) for the excess energy. for 4 months I made +£180
  • Spring and late autumn months my electric costs were only about £2.2 per day inc standing charge I’m -£122
  • Winter I’m paying around £3.50 per day inc standing charge so - £630

Realistic Caveats: The inverter will provide around 5kW draw max and then start using grind power above that, inverter lifespan is around 10-15 years and panel lifespan around 20…we will pretend no degradation, no charging losses and 100% efficiency. I’m also going to assume an inverter replacement halfway through the 20 year period at £2800 and that batteries last 20 years maintaining 100% efficiency (which they won’t). No faults with the system for 20 years are assumed. Panels cleaning costs are not included

  • My electric Bill without solar (6 months at 10kW and 6 months at 8kW per day = £711 for the other 6 summer months £586 all inc standing charge Total £1297 per annum

With solar

  • My electric Bill 4 months +£180 spring autumns £-122 ..that’s +£60 for the period.
  • The winter 6 months -£630
  • Inverter amortised replacement cost of once within 20 years -£140
  • Total cost 570+140 = £710 per annum, my saving being £587 per year.

So a 6kW system with 5kW battery costing £13.5K if you can actually get one for that (which I doubt), over a 20 year assumed life will save you £11750. However you spent £13.5K, so you will be £1760 down on the deal. At this time your inverter, batteries and panels will need replacement.

I have taken the most favourable view and it simply doesn’t cost in at even current electricity prices!

Contact me

    @“Cuprajake”#p4066Depends who you ask! Modern panels from reputable companies generally come with a minimum 25 year warranty so depends how you are defining obsolete. Old laptops in general continue to work - it’s our expectations and uses cases which makes them obsolete. So although panels from a reputable supplier should still be supported in a couple of decades from now - the industry is likley to have changed - the panels and invertors in 2040 and beyond will likely be cheaper and more efficient.

      sorry more how they degrade? do they loose the ability to charge as quick,

      Decent De1pro v1.45 - Niche Duo - Niche Zero - Decent is the best machine ever made -

        Cuprajake sorry more how they degrade? do they loose the ability to charge as quick,

        • Lithium Batteries degrade because of, age & cycles
        • Solar Cells degrade at approx 1% per year (from the best info I could fine, because of many different effects.
        • Inverters degrade primarily due to the big electrolytic capacitors, and less so because of the siilicon. It’s almost a certainty that 10 years or so is replacement time.

        Contact me

          The panels will over time reduce their ability to capture the solar - i think mine will drop to 80% efficient after X years.

          I am on my second invertor in 12 years - that was 1k to replace - then a cable went on a panel - which took out the entire string - took minutes to fix but over 1k in scaffolding costs….

          If it had not been for the excellent FIT tariffs I would not have bothered back then.

          There is so much incorrect information regarding solar PV in the last several posts that I wouldn’t know where to start to correct it 😂

            I am sure I have used the wrong terminology along the way 😂

            Del_UK There is so much incorrect information regarding solar PV in the last several posts that I wouldn’t know where to start to correct it 😂

            Please correct it…I only posted from quotes I’ve had and information about the equipment gleaned over 7 years plus my own circumstances. If I have things wrong, I’d like to know what I am missing. 2 or 3 Quotes of 21 to 23K for just under 4kW with batteries and inverter, when my annual leeccy bills are £1300, simply don’t make sense? Especially as that was for my Garage roof with no scaffolding requirements!

            Contact me

                Pompeyexile Since the introduction of solar specifically, I hear people talk about when installing any sort of heating system other than a gas boiler about payback etc and ‘ooh it costs so much you would never get your money back or it would take years’.

                I think it depends on the alternative to your action. The alternative to no boiler is no hot water/heating, but If you have a boiler and get a more efficient one, then you might be more interested in ‘payback time’.

                With solar PV the alternative is power from the grid, so people tend to look at payback time as the main factor (the others being environmental, psychological etc.).

                DavecUK Please correct it…I only posted from quotes I’ve had and information about the equipment gleaned over 7 years plus my own circumstances.

                I have had solar panels installed 4 months ago, so I can give you some real-life information rather than estimates. My system has 12 panels (capacity is 4.5kw) and I also have a 7.2kWh battery. The total cost was £9,825 (£5,245 for the PV and £3,977 for the battery - got it via Solar Together group buy scheme). Yesterday was a sunny day and solar yield was 22kWh. Today we hardly saw a ray of sun so the yield is only 3.4kWh. The total yield for March has been 278kWh (with a few days to go). The yield in February was 284kWh, January was 204kWh. We didn’t have the panels during the summer months, but obviously I expect it to produce considerably more. I have not yet had any payment for energy I export to the grid, but I have a pending request with a supplier that currently pays 6p per kw. Eventually I hope to move to Octopus, which currently has the best export tariff at 15p per kw.

                Payback time is very hard to predict. We still don’t know how much we will save, and the numbers will change. We are currently on a fixed rate till October, then that will end. We don’t know what the prices will be in November, let alone in years to come. Appliances efficiency may change in the future. We might have an electric car. It’s hard to predict what will happen tomorrow, so how can we know what will be in a decade? If we save £80 per month, the system would be ‘free’ in ten years. If we only save £40 per month, it might be 20 years before ‘payback’.

                Although payback is definitely important, and I doubt if I would install solar if I could see into the future and know that buying energy from the grid would be better economy, I still think there is more to it than just payback time. I like the idea of getting energy from the sun, which would otherwise just be wasted. It just makes sense and makes me feel better when the sun is out and I can bake bread/roast coffee/wash cloths/dishes with energy hitting my roof. I like the fact that it’s renewable and environmentally friendly. I like that fact that it reduces my reliance on the grid, so if there is war/crisis/greed/whatever and prices will stay high or become higher, I have this little shield and I’m buying less from the grid.

                It’s not that I’m not hoping for a good ‘payback time’, but I look at it slightly differently than be all end all. On day 1, the system cost me X. Every month that I’m paying less for electricity, the cost of the system to me reduces. So even now, 4 months after I got it, it’s already a little cheaper for me to have it than it was initially. In a few years time it would be considerably less. Eventually, I do expect it to cost me nothing, and hopefully it will still be there on the roof and produce free electricity on nice sunny days. And if it doesn’t - then I’m sure it still won’t be my worst financial decision. Probably not even close.

                      Doram The total cost was £9,825 (£5,245 for the PV and £3,977 for the battery - got it via Solar Together group buy scheme).

                      Your cost was incredibly cheap for what you got…….

                      Contact me

                          DavecUK Your cost was incredibly cheap for what you got…….

                          I know there is a trend here to to try and find the most expensive way to do things, but I’m old school so prefer to get a good deal when possible. ;-)

                              Doram That price is about what I’d estimate., and much more realistic than the £20k previously stated… The prices are at least half what they were 5 years ago

                              Warranty periods vary from manufacturers, but Solar Edge offer 12+ (sometimes 20) years on their inverters and 25 on optimisers. A replacement will be £400-1200 depending on model at current prices.

                              Panels usually out preform their spec sheet out of the box, my Perlight 295s have a measured max of about 309w. It therefore takes a few years before they degrade to their official wattage, and even then they won’t degrade that much. Manufactures usually guarantee 80% after 10 or 15 years, but it’s unlikely they will fall anywhere near that. A system I fitted for someone nearly 11 years ago was attacked by squirrels (add that to the list of downsides 😁). After repairing it, it was producing 3.9kw of power at its peak. It is a 4.1kw system on a 4kw Sunnyboy inverter. And, those panels have never been cleaned.

                              Another site I fitted last year, 5.8kw of panels but only a 3.68kw inverter, produced 790kwh in July last year, and has produced 330kwh so far this month. Winter reduces it, but to say you won’t get much at all is a bit of a leap.

                                  Del_UK Doram That price is about what I’d estimate., and much more realistic than the £20k previously stated… The prices are at least half what they were 5 years ago

                                  My system was actually a few hundred quid less than I said. The total price I quoted included some extra bits, such as the bird (and hopefully squirrel) protection net…

                                  For anyone thinking I got inferior components, then no: QCELLS 375W Panels, Solis Hybrid inverter, Pylon Batteries. Panels have a 12-year product warranty and 25-year linear performance warranty, Inverter and batteries have at least 10 years warranty, but I think more (can’t remember for sure). Installation and service were first class.

                                      Doram Some good kit there. I like the Solis stuff, and Qcells seem well built too. Not tried/fitted the Pylon stuff, but it’d be something I’d consider as it’s cheap and you can easily AC couple it and monitor with my existing Solaredge software, whereas a lot of the kit doesn’t play nice with Solaredge.

                                        Doram I know there is a trend here to to try and find the most expensive way to do things, but I’m old school so prefer to get a good deal when possible. ;-)

                                        I had 3 quotes for PV on the garage, none of them were less than 15K for 4kw and battery…ridiculous prices.

                                        Contact me

                                            DavecUK I had 3 quotes for PV on the garage, none of them were less than 15K for 4kw and battery…ridiculous prices

                                            I also had a couple of quotes for considerably more, but also another one very similar to the one I went for. As with everything, I guess you need to shop around.

                                                Doram I also had a couple of quotes for considerably more, but also another one very similar to the one I went for. As with everything, I guess you need to shop around.

                                                Perhaps it’s just the area I live in…

                                                Contact me

                                                    DavecUK Perhaps it’s just the area I live in…

                                                    Maybe. I live in a deprived area of the UK - Cambridge… :)

                                                        Doram Maybe. I live in a deprived area of the UK - Cambridge… :)

                                                        Perhaps, you saw the link, and I assure you my prices from 3 companies have been so expensive it couldn’t possibly be worth it? (If I could get it at a sensible price, I would do it.

                                                        Contact me

                                                            DavecUK If I could get it at a sensible price, I would do it.

                                                            The other reasonable quote I got was from E.on solar. Prices may have gone up since, but maybe worth checking?