Most installers will tell you to point solar panels south. But many roofs face east and west, and flat roofs can take panels either way. So are east-west solar panels a poor second choice? Not always. They make less power over a year, but they spread it across the morning and evening, when many homes use the most electricity. This guide shows the trade in numbers, so you can decide for your own roof.
Key takeaways
In the UK and Germany, east-west panels make roughly 10 to 20 percent less power a year than the same panels facing south.
They make more in the early morning and late afternoon, so more of the power is used at home instead of sold cheaply.
On a flat roof you can usually fit more east-west panels, which can make up the gap.
How east-west solar panels spread power across the day
A south-facing panel looks straight at the sun as it climbs to its highest point around midday. An east-west system splits the panels into two groups. One group catches the morning sun, the other the afternoon sun. Neither group faces the sun head-on at noon, so the peak is lower. But the system starts earlier and finishes later. The chart below shows a 4 kW system on a clear June day in southern England.
| kW | South-facing | East-west |
|---|---|---|
| 06:00 | 0.1 | 0.3 |
| 07:00 | 0.4 | 0.8 |
| 08:00 | 0.9 | 1.3 |
| 09:00 | 1.6 | 1.7 |
| 10:00 | 2.3 | 2 |
| 11:00 | 2.8 | 2.1 |
| 12:00 | 3.1 | 2.2 |
| 13:00 | 3.1 | 2.2 |
| 14:00 | 2.8 | 2.1 |
| 15:00 | 2.3 | 2 |
| 16:00 | 1.6 | 1.7 |
| 17:00 | 0.9 | 1.3 |
| 18:00 | 0.4 | 0.8 |
| 19:00 | 0.15 | 0.4 |
| 20:00 | 0.05 | 0.1 |
Hourly averages for 4 kW of panels at a 15 degree tilt with no shade. The east-west system has 2 kW on each side. Rounded example figures.
Source: Everyday Solar Lab worked example, 2026
The south-facing system peaks at about 3.1 kW around midday. The east-west system never goes above 2.2 kW, but it makes more before 9 am and after 5 pm. Across the whole day it makes about 92 percent of what the south-facing system makes.
Tip South of the equator, swap south for north. In Australia and New Zealand the sun crosses the northern sky, so north-facing panels make the most power and east-west is compared against north.
How much less power do they make in a year?
June flatters east-west panels. In summer the sun rises in the north-east and sets in the north-west, so both sides get long hours of light. In winter the sun stays low in the southern sky, and the east and west sides see much less of it. Over a full year, east-west solar panels usually make 10 to 20 percent less than south-facing ones at the same tilt. A shallow tilt narrows the gap, and a steep tilt widens it.
To see the figures for your own address, try the free PVGIS calculator from the European Commission's Joint Research Centre. Enter your location, set the azimuth to 0 for south, then run it again with -90 and 90 for the east and west halves.
When the power arrives matters as much as how much
Power you use at home saves you the full price of electricity. Power you send to the grid usually earns much less. In the UK, many export tariffs pay a fraction of what you pay to buy a unit, and in Germany the feed-in rate for new small systems is also well below the price of grid power. So a system that makes slightly less, but more of it when you are home, can be worth almost as much.
A worked example
Take a family in southern England with room for 4 kW of panels. Electricity costs them 25p a unit, and their export tariff pays 5p.
Facing south, the panels make about 3,800 kWh a year. Facing east and west, they make about 3,300 kWh, roughly 13 percent less.
With south-facing panels the family uses 35 percent at home, which is 1,330 kWh. The other 2,470 kWh goes to the grid.
The flatter east-west curve lifts home use to 42 percent, about 1,390 kWh. Only 1,910 kWh is exported.
Multiply home use by 25p and exports by 5p. South earns about £456 a year and east-west about £443, a gap of only £13.
Table 1. The worked example in numbers
Per year | South-facing | East-west |
|---|---|---|
Power made | 3,800 kWh | 3,300 kWh |
Used at home | 1,330 kWh (35%) | 1,390 kWh (42%) |
Exported | 2,470 kWh | 1,910 kWh |
Yearly value | £456 | £443 |
Warning These prices are examples. If your export rate is close to the price you pay for electricity, south-facing panels win by a wider margin. Run the sums with your own tariff before you choose.
Flat roofs: where east-west solar panels shine
On a flat roof, south-facing panels sit in rows on tilted frames. Each row needs a gap behind it so it does not shade the next one, and that gap wastes space. East-west panels sit back to back in a low tent shape, so the rows can almost touch. On the same roof you can often fit noticeably more of them, which can close most of the gap in yearly output.
Other reasons installers like east-west on flat roofs:
The low frames catch less wind, so they often need less ballast to hold them down.
The two sides peak at different times, so a smaller inverter can handle the whole system.
The output curve is gentler, which suits homes without a battery.
Note A smaller inverter than the total panel size is normal for east-west systems. On the sunniest hours a little power is clipped. Ask your installer to show the expected loss before you agree; it is usually small.
Should you choose east-west or south?
If your roof faces south and you have room for all the panels you want, south still makes the most power. Choose east-west solar panels when:
your roof faces east and west, so south is not an option;
you have a flat roof and want to fit as many panels as possible;
your export rate is low and you use most power in the morning and evening.
A battery changes the sums, because it stores midday power for the evening. If you are thinking about one, read how big a home battery you need before you decide on panel direction.
Frequently asked questions
Do east-west solar panels work in winter?
Yes, but they lose more than south-facing panels in winter, because the low sun stays in the southern sky. Expect most of the yearly gap to come from November to February. In summer the two layouts are much closer.
Can I mix south and west panels on one system?
Yes. Panels facing different ways should go on separate strings, or use an inverter with two inputs or microinverters, so one side does not drag the other down. Adding a few west-facing panels is a common way to stretch output into the evening.
