There are many factors to think about if you’re trying to decide if installing solar PV (and possibly battery storage) is worth it for you.
The first question is, what do you want it for? Generally, people fall into 2 camps when answering this question. They either want it to help the planet, or to make a good investment. And it’s not a dichotomy; many people do it for both these reasons.
If you want it to help the planet, then the main factor to consider is your roof space. Any power you generate will replace power that comes from the grid, some of which comes from fossil fuels. Good stuff. But if you can only fit 4 panels on your roof, then the power you can generate won’t be very much, in which case there’s probably other ways you can more effectively spend your money to help the planet. If you can fit 12 panels on your roof, then you’ll offset triple the amount of carbon than you would if you can fit 4.
As well as the size of your roof space, it’s also important to look at which direction it is pointing, and if it is shaded. A lot of people think that you should only put solar on south facing roofs, and while it’s true that this is the best orientation for a solar panel in the northern hemisphere, if your roof points due east or due west, then panels that you put on it will yield around 82% of south facing panels. And if you have an east roof, there’s a good chance you have a west roof. Put panels on both roofs and your power will be generated throughout the whole day, giving you more chance to use it directly, which can mean that you can spend a little less on battery storage.
And if you’re getting solar panels on your south roof, and have high usage, you might want to put them on the north roof too. They’ll give you about 60% of what the south facing panels will.
I’ll try and put together a guide to maximizing your roof space to explain this further in the future.
A note on shading. It can affect the array more than you would expect it to. Without being optimised, a string of panels will yield as much as the lowest performing panel. So, when one panel in a string gets shaded or, worse, damaged, then unless it’s been optimised, the performance of the whole array is brought down.
Turning to finances now, and of course everything I’ve written so far applies here too; the more power you generate, the more money you can save or earn through export. The next factor dictating whether solar is a good financial investment is how much power you currently use. If you use lots of power, then you have more potential to save money. Typically, if you’re spending more than £70 per month on electricity, then solar PV may be worth looking at. And the more over £70 it is, the better an investment that solar is likely to be.
Power that you don’t use, and export to the grid, will still earn you money. See this page for a list of Smart Export Guarantee (SEG) rates that energy providers offer. But you’ll earn typically 15p per kWh, compared to around 24p per kWh that you’ll save for power that you use.
In summary, if you’re trying to work out whether solar is right for you, the main factors to consider are:
Do you have available roof space that is a good size, without significant shading and preferably facing not north? The more panels you can fit, the better it’ll be for both the planet and your bank balance.
Do you spend a reasonable amount on electricity? I would suggest that anything more than £70 per month makes solar worth looking into.
If you live in the Southwest and would like a free design consultation to see if solar would be worth it for you, fill in the contact form below.