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Solar - what do I need to know?

EssexHebridean
EssexHebridean Posts: 23,862 Forumite
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edited 11 January 2024 at 6:53PM in Green & ethical MoneySaving
** edit - the house described here is not the one we are now living in, so please bear in mind the description here regarding orientation is out of date!* We are hoping to be moving into a house later this year, and will be looking to get solar panels installed, so I’m starting to try to get my head around it. If we get the house we’re hoping for then it’s a standard terrace with a tiled roof. Next door have a solar array on the front - which faces north east - which seems a little odd to me, but presumably they have their reasons. It follows however that the back faces south west - and that is where we would ideally like to place our panels, unless there is some reason why this isn’t possible. (There is decent access to the rear of the house). 

What do I need to know? What have other people learned from experience that they wish someone had told them sooner? How much work is involved? How easy is it to add battery storage - is this achievable in a small terraced house or does it require more space than that? How much of my usage could I reasonably expect the panels to cover say during the summer months - I’m aware that without batteries there will be big chunks of time during the winter where the answer would be “nothing”. What is the minimum size array to make it worth the bother, and similar question for batteries too. 

All info welcomed - and if there are any links to solid information that ai should be reading (Solar panels for Dummies, probably!) then please do pop them into the thread for me!  Let’s have your idiots guide to solar panels please! 

TYVM. 🙂
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Comments

  • ABrass
    ABrass Posts: 1,005 Forumite
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    edited 15 January 2023 at 7:24PM
    Have a browse through some of the threads here, you'll pick up most of the details.

    Talk to your neighbours and see why they went NE, and how much they get out of it. It may be that it's worth getting both aspects done.

    Installation should take a day or two at most. Often with scaffolding but sometimes just with ladders.

    Solar power is absurdly variable. Without a battery to save up the surpluses you'll export most of your power to the grid. This is fine and you will get paid for it. With a battery you'll use a lot more but you'll still export a fair bit. The winter months have very little generation and the summer too much.

    Batteries may or may not be worth it for you, they're borderline at the moment.
    8kW (4kW WNW, 4kW SSE) 6kW inverter. 6.5kWh battery.
  • EssexHebridean
    EssexHebridean Posts: 23,862 Forumite
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    Good gen - thank you, getting both sides of the roof done hadn’t occurred to me I must admit! 
    🎉 MORTGAGE FREE (First time!) 30/09/2016 🎉 And now we go again…New mortgage taken 01/09/23 🏡
    Balance as at 01/09/23 = £115,000.00 Balance as at 31/12/23 = £112,000.00
    Balance as at 31/08/24 = £105,400.00 Balance as at 31/12/24 = £102,500.00
    SOA CALCULATOR (for DFW newbies): SOA Calculator
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  • Alnat1
    Alnat1 Posts: 3,631 Forumite
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    Is this a modern or older terrace? Will you have a loft space or is the house likely to have an attic bedroom? Is there a (dry) cellar? Thinking of where an inverter/battery could be sited in a terraced house.
    Barnsley, South Yorkshire
    Solar PV 5.25kWp SW facing (14 x 375) Lux 3.6kw hybrid inverter and 4.8kw Pylontech battery storage installed Mar 22
    Daikin 8kW ASHP installed Jan 25
    Octopus Cosy/Fixed Outgoing 
  • Ectophile
    Ectophile Posts: 7,766 Forumite
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    If you are thinking about batteries, then make sure you get an inverter that's compatible.  That way, all the installer needs to do is mount the batteries next to the inverter and run the wires across. My battery is pretty modest, smaller than a suitcase.
    If it sticks, force it.
    If it breaks, well it wasn't working right anyway.
  • The true cost of electricity varies according to the time of day.  It tends to be most expensive at about the time the sun is in the south west so that would seem to be the optimum orientation for your panels.  
    Reed
  • Krakkkers
    Krakkkers Posts: 1,272 Forumite
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    How much room do you have on the SW roof? How many panels could you fit on there?
  • jimjames
    jimjames Posts: 18,264 Forumite
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    How much of my usage could I reasonably expect the panels to cover say during the summer months - I’m aware that without batteries there will be big chunks of time during the winter where the answer would be “nothing”. What is the minimum size array to make it worth the bother, and similar question for batteries too. 

    TYVM. 🙂
    Even with batteries it's unlikely you will generate much over the winter to cover your use especially in November/December. You're obviously aware of the monthly variation but as well as generating more over the summer the day is extended so that higher amount is spread over a longer time

    http://solar-panels-review.321web.co.uk/index.php/yearly-comparison-of-solar-pv

    You can see here that panels started at 0800 and finished at 1545 in December
    http://solar-panels-review.321web.co.uk/index.php/solar-power-month-by-month/12-monthly-data/12-monthly-uk-solar-panel-electricity-output-for-december

    yet in June that was 0510 and 2100 so 16 hours of generation compared under 8 in winter.
    http://solar-panels-review.321web.co.uk/index.php/solar-power-month-by-month/12-monthly-data/16-monthly-uk-solar-panel-electricity-output-for-june

    If you can time loads that use electricity to daytime then you will make more savings. Depending on your location (Essex?) you'll get more generation that more northerly places.
    Remember the saying: if it looks too good to be true it almost certainly is.
  • dunstonh
    dunstonh Posts: 118,550 Forumite
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    For reference, the site that jimjames links to with its useful data is an array of 14 panels of 210w = 3kWp 

    If you are installing today, the panels would be circa 410w and efficiency has improved (although ignore the efficiency differences as margin of error).  So, a similar-sized array in terms of construction installed today would generate almost twice as much energy.

    We have a 24 panel (final number should be confirmed later today) being installed around April on a SW face.    There could well be a second stage installed on a NE face.  NE is not as good but it can still be viable.   North is not viable but upto about NNE can be.

    We are having a 8.6kWh battery initially (expanded it with the second stage later on).   And we are on economy 7.  So, when the solar doesn't generate enough, it will top the battery up from the off peak rate (just under 7p kWh at the moment).




    I am an Independent Financial Adviser (IFA). The comments I make are just my opinion and are for discussion purposes only. They are not financial advice and you should not treat them as such. If you feel an area discussed may be relevant to you, then please seek advice from an Independent Financial Adviser local to you.
  • EssexHebridean
    EssexHebridean Posts: 23,862 Forumite
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    edited 16 January 2023 at 12:44PM
    Alnat1 said:
    Is this a modern or older terrace? Will you have a loft space or is the house likely to have an attic bedroom? Is there a (dry) cellar? Thinking of where an inverter/battery could be sited in a terraced house.
    late 50's/early 60's as far as we know. Yes to a loft, no to a cellar.
    Edit to add - at the house we are hoping for there is also an original construction reasonably sized brick built shed which could potentially be an option? 

    Ectophile said:
    If you are thinking about batteries, then make sure you get an inverter that's compatible.  That way, all the installer needs to do is mount the batteries next to the inverter and run the wires across. My battery is pretty modest, smaller than a suitcase.
    This is the sort of thing that I would simply have no idea about right now, so thank you for mentioning it. I presume if the same installer does the lot they would advise anyway.

    The true cost of electricity varies according to the time of day.  It tends to be most expensive at about the time the sun is in the south west so that would seem to be the optimum orientation for your panels.  
    This was exactly my thinking. 

    Krakkkers said:
    How much room do you have on the SW roof? How many panels could you fit on there?
    Unknown at present - next door appear to have 10 though, which also seems to be relatively standard for our local area for similarly sized houses. 

    @jimjames thank you - great info from those links. We're in the interesting position of potentially going from load shifting almost everything overnight on E7, to having to switch the mindset to run things during the day if we end up with the solar! Some of the tables on that site make really interesting reading though, and help to give an idea of what might be reasonable to expect. 

    And yes @dunstonh - the possibility of being able to revert back to E7 to top up batteries on the cheaper rate had already occurred to us. It would obviously work best if we were willing to go to EDF though (assuming their maintained their position of pricing on the day/night split), which right now we really wouldn't be. Thanks for the clarification about the size of array the JimJames links refer to also. Also - that information that todays panels are 410w - that makes a lot more sense of the array sizes I'm most commonly seeing locally to us. Most of what I'd seen previously said 250w. 

    🎉 MORTGAGE FREE (First time!) 30/09/2016 🎉 And now we go again…New mortgage taken 01/09/23 🏡
    Balance as at 01/09/23 = £115,000.00 Balance as at 31/12/23 = £112,000.00
    Balance as at 31/08/24 = £105,400.00 Balance as at 31/12/24 = £102,500.00
    SOA CALCULATOR (for DFW newbies): SOA Calculator
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  • Screwdriva
    Screwdriva Posts: 1,332 Forumite
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    edited 16 January 2023 at 2:02PM
    Lots of excellent collective experience on this forum, already reflected in the responses so far. 

    I’ll add to them by sharing one key bit of advice: Always purchase quality brands:

    For me, those are:

    1. For panels: Sharp / Hyundai / Solarwatt / Panasonic / REC / Sunpower 400+ Watt panels

    2. For standalone inverters: Enphase or SolarEdge or GivEnergy w 20+ year warranty.

    3. For batteries w/ built in inverter : Tesla or Myenergi Libbi or GivEnergy (battery really makes sense only if you have a heat pump or EV)

    I’ve attached feedback from an installer who tried getting after sales support from Growatt, a known Chinese brand on these forums, to help illustrate why I would only purchase from the lists above. 
    -  10 x 400w LG + 6 x 550W SHARP BiFacial Panels + SE 3680 HD Wave Inverter + SE Optimizers. SE London.
    -  Triple aspect. (22% ENE/ 33% SSE/ 45% WSW)
    -  Viessmann 200-W on Advanced Weather Comp. (the most efficient gas boiler sold)

    Feel free to DM me if I can help with any energy saving!
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