How to Compare Solar Panel Installers in Sussex: Roof, Output, Inverter and Handover

If you are comparing solar panel installers in Sussex, look past the number of panels and ask how the installer arrived at the design, generation assumptions and roof layout.

Two proposals with similar headline capacity can differ in roof suitability, shading, inverter design, scaffolding, warranties, monitoring and the quality of the handover.

Start with the roof before the equipment

Solar panels can remain on a roof for years, so this is the wrong time to ignore existing roof defects.

Ask the surveyor to consider:

• tile/slate condition;
• previous repairs;
• signs of leaks;
• roof age;
• ridges/flashings;
• usable roof area;
• structural concerns where relevant;
• safe installation access.

If the roof needs meaningful work, coordinate that before fitting panels where practical.

A roofer may be needed separately if defects fall outside the solar installer's scope.

Orientation and shading should be part of the design

Ask the installer what assumptions they have made about:

• roof direction;
• pitch;
• shading from trees;
• chimneys;
• dormers;
• neighbouring buildings;
• different roof faces.

A design that simply fills every possible space may not be the most useful layout.

If shading materially affects a section of the roof, ask how the system design accounts for it.

Compare generation assumptions, not sales promises

A solar proposal will often include an estimated annual output.

Ask:

• what data/model produced it;
• what shading assumptions were used;
• whether degradation is considered;
• whether the figure is generation or financial saving;
• what electricity price assumptions sit behind any savings illustration.

Generation and bill savings are not the same thing.

How much you save depends on when you use electricity, your tariff, export arrangements, system performance and future energy prices.

Treat forecasts as planning estimates, not guarantees.

Panel count is only one design variable

Compare:

• panel model;
• panel rating;
• total array size;
• roof coverage;
• mounting system;
• inverter design;
• monitoring;
• warranties.

Do not assume that the highest individual panel wattage automatically creates the best system for the roof.

Physical dimensions, roof geometry and electrical design all matter.

The inverter deserves attention

The inverter is central to the system.

Ask:

• model and rating;
• mounting location;
• ventilation/clearance needs;
• noise;
• warranty;
• monitoring;
• whether future battery integration is possible;
• what happens if one roof section is shaded.

If the inverter is going in a loft, garage or utility area, look at practical access for future servicing.

Battery or no battery?

A battery can be useful, but it should solve a defined problem.

Ask what the battery is intended to do:

• increase use of your own solar generation;
• charge during cheaper tariff periods;
• provide backup where supported;
• support export/tariff strategies.

Request the solar-only option and solar-plus-battery option separately.

That makes the additional cost and function easier to understand.

Do not forget scaffolding and access

A quote should say whether safe roof access is included.

Check:

• scaffolding;
• edge protection;
• difficult rear access;
• conservatory roofs;
• neighbouring land;
• shared drives.

A cheap quote that excludes scaffolding is not directly comparable with one that includes a complete access plan.

Planning and Building Regulations are separate questions

Many householder solar installations in England can be permitted development if the relevant limits and conditions are met.

That does not mean every property is automatically covered.

Listed buildings, designated areas, unusual mounting positions and other constraints can change the planning position.

Separately, building and electrical safety requirements still matter.

Ask the installer what permissions, notifications and certification apply to your exact installation.

Electrical route and equipment location

Discuss:

• cable path from roof to inverter;
• inverter position;
• route to consumer unit;
• isolators;
• meter area;
• internet/network connection for monitoring;
• battery location if included.

You should know where visible equipment will end up before installation day.

Export arrangements and paperwork

If you expect to export electricity, ask what needs to happen with the network/operator and electricity supplier.

Do not assume the installer controls every part of that process.

At handover, retain:

• final system layout;
• equipment datasheets;
• warranties;
• electrical certificates;
• commissioning information;
• monitoring login;
• network/export paperwork where applicable;
• installer contact details.

Keep these with the property records.

Landlords and property managers

For rental property, decide who will:

• own monitoring accounts;
• see generation data;
• respond to faults;
• manage inverter/battery access;
• retain warranties;
• explain the system to tenants.

Also think about future roof maintenance. Record isolators, cable routes and equipment positions clearly.

Using TradeKind

You can browse solar panel installers across Sussex or post the project.

A useful brief might say:

“Detached house in Lewes. Main rear roof faces roughly south-west, tiled roof, chimney causes afternoon shade on one section. Roof covering appears sound but is around 20 years old. Interested in solar-only and solar-plus-battery options with full scaffolding included.”

That gives an installer a real design brief.

Before accepting the quote

Check:

• roof condition;
• orientation/shading;
• array layout;
• generation assumptions;
• panel specification;
• inverter;
• battery option;
• scaffolding;
• cable/equipment positions;
• planning/compliance route;
• handover documents.

A strong solar quote explains the whole system, not just how many panels fit on the roof.