Sunlight to solar panels and greenhouses: the planning position

If a neighbour's extension will put your solar panels or your greenhouse in shadow, the planning system gives you less protection than you probably expect. There is no right to sunlight in planning law, the standard daylight and sunlight tests do not assess equipment, and no policy sets a threshold for how much generation you are allowed to lose.

Loss of output can still be a material consideration. It carries limited weight, and how you present it decides whether an officer can do anything with it.

Whether loss of sunlight to panels is a material consideration

A material consideration is anything that relates to the use and development of land and is fairly and reasonably related to the application. The output of an existing renewable installation on a neighbouring property meets that description, so a case officer can take it into account.

That is different from saying it will change the outcome. Three things limit the weight it carries.

There is no policy test. Compare that with daylight to a habitable room, where BRE 209 provides numbers an officer can apply, and with garden amenity, where the sun on ground test does the same. For panels there is nothing.

There is no protected expectation. Installing panels does not create any entitlement to the sunlight that reaches them, in the same way that planting a garden does not.

And national policy pulls in both directions. It supports renewable energy generation, which favours the panels. It also supports householder development and the efficient use of land, which favours the extension.

How the argument tends to be treated

Officers and inspectors deal with this by weighing the actual loss against the actual benefit of the proposal. That means the objection lives or dies on evidence of the loss.

Objections that assert the panels will be shaded, without saying by how much or when, are recorded and given no weight. Objections that quantify the loss get engaged with, even where they do not carry the day.

Do not present appeal decisions as if they bind the council. They are indicative of how inspectors have approached similar arguments, and a case officer may find them useful, but each case turns on its own facts.

Greenhouses and food growing structures sit in a slightly different place. Loss of sunlight to a greenhouse can be framed as loss of amenity to the garden as a whole, which does have a test behind it. That framing is usually stronger than treating the greenhouse as equipment.

The evidence that supports an objection

Four items, in order of usefulness.

A shadow study showing the array under existing and proposed conditions, at hourly intervals, on 21 March, 21 June and 21 December. This is the same method used in an Overshadowing Study, and it can be produced from the applicant's own drawings plus a measured position for the array.

A modelled annual output comparison, using the array's orientation, tilt, capacity and the shading geometry, showing the estimated reduction in kilowatt hours per year. Use a recognised modelling method and say which one. An installer or an accredited assessor can usually produce this.

The array's installation details: capacity, panel positions, inverter arrangement and whether the strings are affected as a whole or in part. String layout matters more than people realise, because partial shading of one panel can reduce the output of a whole string.

And, where relevant, evidence of the financial arrangement the installation sits within, though this is the weakest of the four because private financial loss is not usually a material consideration in itself.

Keep the objection to the planning point. The effect on renewable generation, and any loss of garden amenity, are planning matters. Loss of property value is not.

The absence of a right to sunlight in planning

Two separate ideas get conflated here, and separating them saves a lot of wasted effort.

Planning assesses the effect of a proposal on living conditions, using the daylight and sunlight tests where they apply. A Daylight and Sunlight Assessment tests windows serving habitable rooms and, separately, sunlight to amenity areas. Neither test looks at a roof-mounted array, because BRE 209 is about people in rooms and people in gardens.

The civil law of rights of light is an easement, acquired over time in respect of light passing through a defined aperture in a building to a room behind it. A solar panel is not an aperture and a garden is not a room, so no easement can arise for either. That is why the civil route almost never helps.

The practical result is that if you want the sunlight to your array protected, the moment to do it is when the neighbouring site is being designed, not after permission is granted.

Design responses that reduce the conflict

Objecting is the weaker move. Proposing a change is the stronger one, and case officers welcome it because it gives them something to negotiate with.

• Reducing the height of the nearest part of the extension by a course or two, which on a single storey rear extension can clear a low winter sun angle
• Pulling the extension away from the shared boundary, even by half a metre, which changes the shadow far more than the same distance in depth
• Changing a pitched roof to a mono-pitch falling away from the boundary
• Setting back an upper storey on the boundary side
• Relocating a flue, aerial or plant enclosure that casts a narrow but damaging shadow across a string

Put the suggestion in the objection letter with a sketch. An officer can ask for an amendment. They cannot invent one.

An illustrative example. A two storey side extension is proposed 800 mm from the boundary, opposite a neighbour's south-facing array. The neighbour's shadow study shows the top two rows of panels shaded from about 14:00 in December, and modelling estimates a reduction in annual output in the low single-figure percentage range. The officer asks for the second storey to be set back 1.5 metres from the boundary, which removes most of the winter shading. The applicant agrees, because the loss is a corner of a bedroom. Nothing about that outcome would have happened without the shadow study.

Framing an objection that officers can act on

Keep it to one page and structure it like this.

1. Your address, the application reference and the date.
2. One sentence stating what you are objecting to and why.
3. The array or structure described factually: position, orientation, capacity, date installed.
4. The evidence, attached: shadow plots and output modelling.
5. The specific change you are asking for, drawn or described precisely.
6. A note that you are content for the officer to contact you to discuss it.

Submit it within the consultation period, which is usually 21 days from the site notice or the neighbour letter. Late representations are considered where they arrive before the decision, but a late objection to a delegated application often arrives after the report is written.

And speak to the applicant. A large share of these disputes settle between neighbours over a drawing, because the change that protects the array is frequently trivial for the scheme.

PlanScope drafts overshadowing and daylight documents structured to UK planning policy, with a "to be confirmed" flag wherever modelling outputs are missing. Councils expect a suitably qualified author for daylight and sunlight work, and professional review is strongly advised. This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. Enter your postcode to see which reports a site is likely to need.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.