*Spoiler alert* – There’s just no way of answering this question with perfect accuracy. We can’t aim to be the UK’s most trusted solar brand if we promise all customers everywhere £xxx savings or xxx% reduction in their energy bills.
The good news is that we can predict with reasonable certainty how much electricity your solar system should produce. Energy production will depend on how many panels you have, the angle and orientation of them and how sunny it is where you live. The ‘sun paths’ in your area will vary throughout the year (and of course some years it’ll be sunnier than others). We look at historical satellite data around your home to give us the best estimate here.
The next variable in the mix is how much of the electricity you’ve produced you’ll actually use. At the time of writing this, the retail price of electricity is much higher than the price you can sell back to the grid – so the more self-generated electricity you use to power your home, the better. This varies a lot between households, depending on things like if you have a battery, whether you’re at home during the day, if you have an electric vehicle and when you use your appliances. The good news is that this one is within your control and the variance here is between 25-85%.
Combining these two factors allows us to calculate an approximate figure for “grid independence” – the percentage of your electricity bill that you will save by installing solar. This could vary from 15% to 95%, so another wide range.
The biggest uncertainty in your savings calculations is the unknown – energy prices have been volatile in recent years and they continue to be tricky to predict. So the best that we or anyone can do is make some educated guesses. We can calculate this for you based on today’s energy price – but just remember to take any energy price forecast with a big pinch of salt.
What does the word “savings” even mean?
It’s worth being mindful of the word ‘savings’ as it can be used ambiguously and generously across the solar market. For example, savings can relate to the price difference between the cost of the same solar system from one company to the next, the energy savings themselves (i.e. using less energy), the savings you could make by offsetting the energy you’re using by the energy you’re selling back to the grid and so on. For customers who choose a finance option, the cost of borrowing (the APR%) will of course affect the calculation of true savings, too.
Is there a standard way companies calculate savings?
The Microgeneration Certification Scheme (MCS) is a set of standards for renewable energy products in the UK. Included in the set of standards is guidance on how to formulate a savings calculation. If your installer is MCS accredited (and please make sure they are!), savings should be calculated using the MCS methodology.
Although the MCS methodology is robust, it still leaves some areas down to the judgement of the installer doing the calculation. For example – how much shading will a particular tree cause? How much of the energy you produce will you use at home? What will energy price inflation be in the future?
Confusingly, this means that two different people calculating the savings from the same system might come out with different results.
So when you’re comparing quotes from different installers, the most important thing to compare is the size of the system and the price. After all, two identical 4kW systems on the same roof will most likely generate the same amount of electricity.
Long story short…
While savings can be estimated, it’s always a good idea to look into all the many benefits of solar, not just focus on the ‘savings’.
At Glowb, we’re committed to helping homeowners better understand how solar could work for them and we pride ourselves on our transparency. That’s why we insist on an on-site survey of your home before we prepare your quote – a quote which will give you a pretty good estimate of expected energy savings, too.