Optimising Solar Performance with an East or West Facing Roof

How to Optimise Solar Performance with an East or West Facing Roof

South-facing roofs get all the love when it comes to installing solar panels. And for good reason.

In the UK they’re positioned perfectly to receive the most amount of sunlight every day. However, that’s not to say that other roof orientations can’t work with solar.

In fact, an east or west-facing roof, with the right set up, can still be highly effective – and in some cases perform BETTER than south facing panels.

We can show you how to maximise your solar panel performance with an east or west-facing roof, 

But first, we need to understand why your roof direction actually matters when it comes to solar.

How Roof Direction Affects Solar Panel Output

Think of south-facing roofs like south-facing gardens — they get sunlight for the longest period of the day.

Because the UK is in the Northern Hemisphere, the sun tracks across the southern part of the sky.

That’s why panels on a south-facing roof typically generate the most energy overall, peaking around midday, when the sun is directly south of us in the UK.

However, east/west-facing roofs still do a great job at generating solar power. Their energy generation just peaks at different times.

As the sun rises in the east, an east-facing roof will mean generation peaks in the morning. However, it’ll generate much less in the evening as the sun moves round to the west.

Once the sun moves to the west, generation will peak for west-facing panels. This will be in the afternoon/evening.

There is a natural period either in the evening or morning where your east or west-facing panels won’t be generating an awful lot of solar.

But, as you’ll soon discover, it’s not just about how much energy you generate. It’s about when you generate it, and how you use it.

Who an East or West-Facing System Works Best For

As solar installers, when we design a system, one of the first things we need to know is what your daily energy habits are.

When do you use most of your electricity? Is it before and after work? Are you out for most of the day? 

Answering these questions will help us design a system that work around you and your energy usage patterns.

As we know, East and West-facing roofs generate the most solar energy in the morning and evening respectively. For the typical weekday routine of many homeowners, this actually aligns perfectly with when you’ll need energy most. 

If you spend most of the day out at work, you’ll first use a lot of your energy in the morning when everyone’s getting up and ready for the day.

This is perfect for east-facing panels. They’ll be able to provide most of your electricity needs through solar power directly. Any excess energy can be stored in a battery for later, or exported back to the grid.

Then once everyone’s out at work, your panels might not be producing maximum output – but that’s ok. No one’s home to use it, so that solar power would either just be exported to the grid, or used to store in a battery which by that point, might be over capacity. 

When it gets to the evening and everyone’s getting back from work/school, it’s then the perfect time to make use of west-facing panels. 

Your panels will again generate energy exactly when your usage peaks. Meaning you use most of your solar power yourself without much need to store or export. 

If this aligns with your routine, an east/west panel layout may be ideal for you.

It may even reduce the need to have a larger battery storage capacity if your generation and usage are naturally synced up. 

However, battery storage can still play a vital, albeit slightly different role in East/West-facing systems…

Battery Strategy for East/West-Facing Roofs

Battery storage plays a slightly different role when your panels are on an east or west-facing roof. The best setup depends on how your system is designed.

Below, are two Tesla Powerwall batteries we recently installed for a customer.

Let’s say you have solar panels split across both your east and west-facing roof slopes.

That setup naturally spreads your solar generation throughout the day — peaking in the morning (east) and evening (west), with a gradual dip in between.

If you’re out at work all day and only home during those peak times, this kind of system aligns really well with how you use electricity. 

You’ll only really need to use a battery to top up your energy on cloudy days, or to carry you through to when your panels are at their peak output again.

We often tell customers with this setup that there’s less pressure to get a larger battery. This is because a large capacity will be wasted if their solar energy is being used right away.

We give the same advice if you spend most of the day at home. With east and west facing panels, you’ll get consistent energy generation throughout the day, and if you’re home a lot, your usage will remain fairly consistent. Again, you won’t be so reliant on a battery here as your usage aligns with the panels’ output. 

But if you only have panels on one side – just east or west – that’s where our advice changes.

With east-only panels, you’ll generate most of your solar while you’re getting ready for work. However, to continue using your solar later in the day, you’ll need to store the energy from the morning sun in your battery.

This is an issue for those with a smaller battery capacity, as you likely won’t be able to store enough energy to power your home throughout the rest of the day. 

The same applies for west-only panels. They won’t produce much until the afternoon, so to get through to the following morning on solar energy will be difficult on a smaller battery. 

In both cases, a larger battery capacity will help carry you through the times when your panels aren’t generating much. This is especially true if you want to make the most of off-peak charging or reduce reliance on the grid. 

Here’s our simplified battery recommendations: 

• Split East/West System + Typical Morning/Evening Usage = Smaller Battery Capacity Needed
• East OR West Roof Only = Higher Need For Battery Storage

Adding a battery still offers flexibility, and is great for carrying you through to when your panels are at their peak output – but a high capacity isn’t always essential with a well-balanced east/west layout.

What is essential though, is that your installer carefully designs your system to optimise for your roof layout.

Design Tips to Maximise Performance

Here are some key tips your installer should be taking into account to optimise solar performance with an east or west-facing roof:

• Panel placement – Installing panels on both east and west if you’ve got both sides available. This will give you a longer generation window and so you can power your home for longer.

• Make use of battery storage – Like we went through earlier, battery storage still has its place in an east/west system. However, if you’ve got panels on both east and west roofs, you can get away with a smaller capacity.

• Optimisers/Micro-Inverters – Your panels will have a limited time in the sun with east/west panels. So, you need to maximise output when they’re in the sun by using tech such as micro-inverters & optimisers. Read more about inverters and optimisers here.

• Smart Tariffs – You may not be storing so much solar with an East and West-facing system, but you may export a fair bit back to the grid. Making sure you’re on a smart tariff that rewards solar export will be important. Find out the best smart tariff for you here.

A well designed east/west system will often outperform a poorly thought-out south-facing one.

That’s where a specialist installer like JD Allen Solar adds value.

We don’t just install whatever system fits on your roof.

We tailor our systems to you and your usage patterns, taking in all external factors to deliver high performing solar panels.

Final Thoughts on East/West-Facing Roofs 

South-facing roofs may be the ideal, but with solar, you don’t need the ‘perfect’ setup to get results.

Take the above installation we completed last year as an example. 

A customer came to us with an east/west split – and no large south-facing roof. They weren’t sure if solar panels were something that would actually work for them. 

After careful consultation, and an in-person survey, we designed a system consisting of 25 panels, and a 15.6 kWh battery capacity. This complemented their usage patterns as they went to work in the morning, and came back in the evening. 

Just one year after installation, the results they saw were extraordinary. Through their first year, with our design and guidance, they were able to reduce their energy bills by over 70%!

Having been unsure if solar could work for their home before – they were blown away by the results.

But it just goes to show, the key isn’t having the perfect roof layout, it’s thought-out design, and matching your system to your routine.

Because when done right, an east/west-facing roof can drastically reduce your energy bills, reduce your reliance on the grid, and also have a positive impact on the planet!

But the importance of smart design cannot be overstated.

If you have an East/West-facing roof, but you aren’t sure what solar panel & battery configuration best suits your roof,

Get in touch with our team today.

As established solar panel installers in South-East London, we’ll help you get the most out of your solar investment, whatever direction your roof faces.

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