The short answer: south-facing at a pitch of 30 to 40 degrees is best. East and west roofs still work well. North-facing roofs produce about half as much and rarely pay back.
Output by roof direction
| Roof faces | Output compared with south | 4 kW system, kWh a year |
|---|---|---|
| South | 100% | 3,400 |
| South-east or south-west | About 95% | 3,230 |
| East or west | About 80 to 85% | 2,720 to 2,890 |
| North-east or north-west | About 65 to 70% | 2,210 to 2,380 |
| North | About 50 to 60% | 1,700 to 2,040 |
These are typical figures for a pitched roof. A certified installer will calculate the figure for your own roof using the MCS method.
Why direction matters so much
Panels produce the most when sunlight hits them square on. In the UK the sun is always in the southern half of the sky, so a south-facing panel catches it for most of the day. A north-facing panel mostly receives indirect light.
Because the cost of the system is the same whichever way it faces, a roof that produces half as much takes about twice as long to pay for itself.
The case for east and west
An east-west split loses 15 to 20% of the output, but it spreads generation across the morning and the evening. Those are the times most households are at home. You use more of the power yourself, at about 26p a unit, and export less at around 15p. For a household that is out all day, an east-west roof can be nearly as valuable as a south-facing one.
The best angle
- 30 to 40 degrees is ideal, and most UK pitched roofs are in or near that range.
- Shallower roofs lose a little output and shed dirt less well.
- Steeper roofs lose a little in summer but do slightly better in winter.
- Flat roofs use angled frames. See solar panels on a flat roof.
Pitch matters far less than direction. Do not rule out a roof because of its angle.
Shade can matter more than direction
A south-facing roof shaded by a tree or chimney can produce less than an unshaded east-facing one. Ask the installer how shading has been assessed in their estimate.
Solar cost calculator UK edition
What would solar cost, and what would it be worth to you?
Six questions. No email address, no phone number. You get a size, a price range, a yearly figure and a payback range, with every assumption shown underneath.
Question 1 of 6
Your estimate
This is an estimate for general information, not a quote. It was correct at the time of publication and uses the assumptions shown. The performance of solar PV systems is impossible to predict with certainty, because sunlight varies from place to place and year to year. Only a survey by a certified installer can give you an accurate design and price. This is not financial advice.
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How we worked this out
| Assumption | Value | Source |
|---|---|---|
| Installed cost | 3 kW solar: £5,000–£6,000; 4 kW solar: £6,000–£8,000; 5 kW solar: £7,000–£9,000; 6 kW solar: £8,000–£11,000; 5 kWh battery: £2,500–£5,000; 10 kWh battery: £4,500–£8,000 | Published UK price guides, government installation cost data (2025/26) and MCS installation costs (2025) |
| Electricity price | 26.32p per kWh | Ofgem price cap, Direct Debit, October to December 2026 |
| Export rate | 15p per kWh | Which? fixed export tariff comparison, April 2026 |
| Output per kW | 850 kWh per year for a south-facing roof | National estimate used by this calculator: a 4 kW system generating 3,400 kWh per year |
| Roof direction factors | South: 100%; South-east: 95%; South-west: 95%; East: 82%; West: 82%; North-east: 67%; North-west: 67%; North: 55%; Flat roof: 90%; Not sure: 82% | Published UK output tables; indicative factors used by this calculator |
| Shade factors | No shade: 100%; Some shade: 90%; Heavy shade: 75% | Calculator estimates; an MCS installer measures shade on site |
| How home use is estimated | Home use of solar power is estimated using an approximation based on MCS 032 | |
Back to is my home suitable for solar panels.
Sources
Correct at the time of publication, 14 November 2026.
- MCS, solar panels: costs and considerations: https://mcscertified.com/consumers/technologies/solar-photovoltaic-pv/
- Ofgem, energy price cap unit rates: https://www.ofgem.gov.uk/your-energy-supply/your-energy-bill/energy-price-cap-unit-rates-and-standing-charges
- Output percentages are drawn from published UK output tables, including Switch Together (https://switchtogether.co.uk/resource-hub/blog/best-direction-for-solar-panels-uk). The kWh column is our own calculation.