How Many Solar Panels Do I Need for My Home in the UK?

How Many Solar Panels Do I Need for My Home in the UK?

 

When they’re first thinking about switching to solar power, one of the most common questions homeowners ask is ‘How many solar panels do I need?’ 

And although it’s asked so often, it’s not always a straightforward answer.

There are so many different factors at play, from your roof size, to your energy usage, your budget and what your actual goals are for your system – and everyone’s different.

At JD Allen we’ve installed systems with as few as 6, and as many as 25 panels on a single home, which is a big difference in power output and price. 

It can be confusing to know what’s best for you – especially when different solar installers give you different advice. 

But whilst there’s no ‘one size fits all’ answer, there are patterns we can follow to understand how many panels someone will benefit from the most.

We’re going to break it down as simply as we can to help you understand:

1. What affects the number of panels you need 
2. How to work out the right number of panels for you 
3. The approach we take as installers when deciding on the number of panels

Let’s dive in!

 

What Affects How Many Solar Panels I Need For My Home?

It’s rarely just a case of putting as many panels as possible on the roof. Whilst roof space does matter, there are several other factors that affect how many panels you need.

Energy Usage

When deciding how many solar panels you need, the first place to start is always your energy usage. 

The more energy your household uses, the more panels you’ll need to meet that demand.

Your energy usage is typically measured in kilowatt-hours (kWh). You’ll find this number on your electricity bill, but here’s a rough guide for most UK homes: 

Home Size	Number of People	Average Energy Usage
1 Bed Flat	1-2 people	1,800 – 2,700 kWh
2-3 Bed House	2-3 people	2,700 – 4,100 kWh
4+ Bed Detached House	4+ people	4,100 – 6,500kWh

(These figures are taken from Ofgem – the UK’s energy regulator)

This may vary for your home depending on how much you’re at your property, whether you work from home or run appliances regularly. 

At JD Allen, we’ll always check your energy bills for the last year, that way we can see your average usage over the last 12 months and tailor a system accordingly.

Roof Layout

The number of solar panels you need is also dependent on how your roof’s laid out.

Obviously the number of panels you get on there is limited by your roof size, but the direction matters too. 

Solar panels work best on south facing roofs in the UK, and so you may be able to get away with less if your roof allows. 

With an east/west facing roof, as they will be in the sun for a shorter time frame, you might benefit from having a few more panels on each side. That way you’ll maximise how much solar you generate.

Budget and Goals

People often assume that if you’re getting solar panels, you’re trying to wipe out your bills entirely, but that’s not always the case 

It’s not always about covering 100% of your energy usage. In fact, the smartest setups balance:

• What you want (e.g. reducing bills, cutting carbon emissions, future-proofing), with
• What you can invest right now 

Some homeowners just want to take 30-40% off their energy bill – others want to go fully off the grid.

You don’t even have to decide everything in one go. We design our systems to be flexible, so that if your goals change at a later date and you want to expand your system – you can do that 

Battery Storage Plans

If you don’t have a battery, you’ll likely need a few more panels than those who do. 

Batteries allow you to store the excess solar that you don’t use, meaning you’ll increase your self-consumption, and likely be able to hit your savings goal with fewer panels. 

Whereas if you don’t have a battery, all your excess solar will go to the grid in exchange for an export payment. 

This is still good news as you’ll be able to make a small amount of money on what you don’t use, but you may need more panels to get the most from your system. 

(Pro tip – combining solar panels and battery storage with the right Smart Tariff will help you use more of the solar you generate, and boost your savings. Learn more about the synergy between them here.)

How Many Solar Panels Do I Need?

We never like to tell people exactly what they need without knowing their exact situation. 

That said, these are some rough guidelines for what might be needed for each home size:

Home Size	Annual Electricity Consumption	Solar Panels Needed (440W)	Average Annual Output
1 Bed Flat (1-2 people)	1,800 – 2,700 kWh	5 – 7 panels	1,800 – 2520 kWh
2-3 Bed House (2-3 people)	2,700 – 4,100 kWh	8 – 12 panels	2,880 – 4,320 kWh
4+ Bed Detached House (4+ people)	4,100 – 6,500 kWh	12 – 18 panels	4,320 – 6,480 kWh
Larger Energy Consumer	7,000+ kWh	20 panels +	7,200+ kWh

This is based on 440W panels being used, which are now commonly used in the industry. If your installer is using lower power panels, you may need slightly more panels than stated in the table above.

Every home is unique, so it’s always difficult to give estimates on what works for everyone. It’s always best to have an accredited installer review your property to find out the exact number of panels you need. Click here for a free consultation call, in which we’ll let you know the optimal number of panels for your property.

Why More Panels Isn’t Always Better

It can be tempting think that ‘The more panels I chuck on my roof, the better returns I’ll get’

And whilst this is true to an extent, there are diminishing returns if how much your producing far-outweighs your needs

Any energy that you don’t use or store from solar panels will be exported back to the grid. Yes you’ll get an export payment from that, but it pays less than saving on bills. 

Meaning that if you’re exporting a lot more than what you need each day, it’ll take much longer to pay off your system.

There’s a sweet spot, where you’re using as much as you can, and exporting very little. For most, this is around 10-12 panels, but it can vary

Normally, any more than 12 panels and you’re looking at exporting a little more – unless you’re a heavy consumer. 

Another factor to bear in mind if you’re trying to add as many panels as you can is scaffolding costs. Especially if your panels are on different sides of the roof, as this will further push up the price of installation.

If you’re looking to add panels onto another roof, the extra cost of scaffolding needs to be justified by the amount those extra panels will generate. Otherwise, again, you’ll find your system payback period is much longer. 

The JD Allen Approach

Whilst we’ve given rough figures, at JD Allen, we don’t believe in cookie-cutter solutions. We know every home is different, and not everyone in solar has the same goals. 

A 10-panel system may be more than enough for a family who are trying to cut down their impact on the environment. 

But for a family trying to remove the burden of their energy bill entirely, they might need extra panels on their roof (and a couple battery storage units too!)

Our team of designers will sit down and listen to your goals, your budget and your energy usage before we even get to your roof. 

Then once we know what you’re looking to achieve, we get to work on making your goals a reality.

We’re a family run business that does things the right way.  We won’t sell you a system we don’t think you need and will only recommend what’s genuinely right for you.

What’s Next? 

Whilst we can’t tell you exactly how many panels you should get yet, you should now know roughly how many solar panels you need for your home.

You’re halfway there to reducing your energy bill, being less reliant on the grid and lowering your carbon footprint.

Now you’ve got a rough idea, your next steps are finding out the exact system that will help you hit your energy goals. 

JD Allen Solar are solar installers in South London, and we offer free estimates and site surveys prior to installation, so we can design a system that works for you.

Simply enquire on the button below, and we’ll help design a system for your home