What Happens During an ECO4 Solar Suitability Survey?
If you are being considered for solar panels through ECO4, a solar suitability survey is an important step before installation. It allows the installer to assess whether your property can safely and effectively accommodate a solar PV system, and helps determine the appropriate system design.
The survey is more than simply checking whether your roof has enough space. An assessor will typically look at the roof’s condition, orientation and inclination, available installation area, shading, electrical arrangements, access, and other factors that could affect the proposed system.
This matters because solar PV performance depends heavily on the property and installation design. Ofgem’s current ECO4 guidance specifically accounts for factors such as solar PV capacity, roof orientation and inclination when calculating the measure’s ECO4 score.
For homeowners, the survey is also an opportunity to understand what is being proposed, where the panels and inverter could be installed, and whether any issues need to be addressed before work begins.
Quick Answer: What Happens During an ECO4 Solar Survey?
During an ECO4 solar suitability survey, an installer or qualified assessor examines your property to determine whether solar PV can be installed safely and effectively. They may inspect the roof, measure available space, assess its orientation and pitch, identify shading, check the roof’s condition, inspect the electrical installation and determine suitable locations for equipment such as the inverter. They may also take photographs, measurements and other information needed for the system design and ECO4 documentation. The assessment helps establish the likely panel layout, system capacity and installation requirements. ECO4 solar PV installations must satisfy relevant scheme and industry requirements, with MCS and other standards applying where appropriate.
ECO4 Solar Suitability Survey: What Is Checked?
| Survey Area | What Is Typically Assessed | Why It Matters |
|---|---|---|
| Roof | Condition, size, pitch and available space | Determines whether panels can be installed safely |
| Orientation | Direction and inclination | Affects expected solar generation |
| Shading | Trees, buildings, chimneys and other obstructions | Can reduce generation |
| Electrical system | Consumer unit, cabling and proposed connection | Helps establish installation requirements |
| Equipment locations | Inverter, cables and other components | Ensures practical system design |
1. The Roof
The roof is one of the first areas an assessor will examine.
They may check:
- Available roof area
- Roof pitch
- Roof orientation
- Roof covering
- Visible signs of damage
- Chimneys and roof windows
- Existing solar panels
- Potential fixing locations
- Access requirements
The survey is not necessarily a structural engineering inspection. If the assessor identifies concerns about the roof structure or condition, further investigation may be required before installation.
2. Roof Orientation and Inclination
The direction your roof faces can affect solar generation.
South-facing roofs are traditionally favourable, but a property does not necessarily need a south-facing roof to benefit from solar PV.
East- and west-facing roofs can also be suitable, depending on the property and system design.
ECO4’s current delivery guidance specifically requires the orientation and inclination of a solar installation to be taken into account when determining the appropriate scoring factor.
This means the surveyor needs accurate information rather than simply recording that the roof is “suitable for solar”.
3. Shading
The assessor will look for potential sources of shading, including:
- Trees
- Nearby buildings
- Chimneys
- Dormers
- Roof structures
- Other parts of the property
Shading can reduce the amount of sunlight reaching the panels and therefore affect generation.
The impact depends on factors such as the size, location and timing of the shade. A tree that shades the roof for part of the day may have a different impact from a permanently obstructing building.
4. Existing Solar Panels
If the property already has solar PV, this will normally be recorded.
This is particularly important under ECO4 because the scheme distinguishes between existing generation capacity and additional capacity installed through an ECO4 project. Ofgem’s current guidance states that where a home already has solar PV, only the additional generation capacity should be included in the relevant ECO4 calculation.
The assessor may therefore record details of the existing system, including the panels, inverter and available documentation where relevant.
5. Electrical Installation
The survey will also consider how the proposed solar PV system can connect to the property’s electrical installation.
The installer may inspect:
- Consumer unit
- Existing electrical equipment
- Cable routes
- Meter location
- Potential inverter location
- Earthing and bonding arrangements
- Space for required equipment
The precise checks depend on the property and proposed system.
The objective is to establish how the solar installation can be integrated safely into the home’s electrical system.
6. Where Will the Inverter Go?
The inverter converts electricity generated by the solar panels into electricity that can be used within the property.
During the survey, the installer may identify a suitable location for the inverter.
Considerations can include:
- Ventilation
- Temperature
- Accessibility
- Distance from the panels
- Cable routing
- Available wall space
- Proximity to electrical equipment
The inverter should not simply be placed wherever there happens to be spare wall space.
7. Measurements and Photographs
The assessor will usually gather information needed to design the installation.
This can include:
- Roof measurements
- Panel installation areas
- Equipment locations
- Electrical equipment
- Roof features
- Access points
- Potential cable routes
Photographs can also form part of the property’s survey and project documentation.
ECO4 requires evidence to support measure eligibility and project and measure-level information, while specific approved solar innovation measures can have additional evidence requirements.
What Could Make a Home Unsuitable for ECO4 Solar?
A survey does not guarantee that solar panels will be installed.
Potential problems can include:
- Insufficient suitable roof space
- Significant shading
- Poor roof condition
- Structural concerns
- Difficult or unsafe access
- Electrical limitations
- Planning or property restrictions
- A system design that does not meet applicable requirements
Sometimes the property is not completely unsuitable, but the original proposed design needs to be changed.
For example, an installer might recommend a different panel arrangement, equipment location or system capacity.
How Is the Solar System Designed?
Once the survey information has been collected, the installer can develop a more accurate system design.
This can involve determining:
- How many panels can reasonably be installed.
- Where the panels should be positioned.
- The expected system capacity in kWp.
- Where the inverter should be located.
- How cables can be routed.
- How the system will connect to the home’s electrical installation.
- What additional work may be required.
Ofgem’s ECO4 guidance uses installed PV capacity in kWp and adjusts the relevant scoring methodology according to factors including orientation and inclination.
What Happens After the Survey?
After the survey, the installer reviews the information and determines whether the proposed solar installation can proceed.
Depending on the project, this can involve:
- Finalising the system design
- Confirming equipment
- Completing ECO4 documentation
- Checking relevant technical requirements
- Confirming installation arrangements
- Addressing any issues identified during the survey
- Arranging the installation
ECO4 requires appropriate evidence and documentation around eligibility and installed measures.
It is therefore important that the survey is completed properly rather than treated as a quick formality.
How Much Does an ECO4 Solar Suitability Survey Cost?
For households receiving solar through an ECO4-funded project, the suitability assessment is generally part of the overall installation process rather than a standalone service that the homeowner should assume they need to purchase separately.
However, arrangements can differ between installers and funding routes.
If additional work is identified — such as roof repairs, structural investigations or electrical upgrades — that does not necessarily mean the work itself is covered by ECO4.
Always ask the installer what is included before agreeing to proceed.
How to Prepare for an ECO4 Solar Survey
You can make the appointment easier by:
- Make sure the assessor can access the property.
- Clear access to the consumer unit and relevant electrical equipment.
- Tell the installer about existing solar panels or batteries.
- Mention any known roof problems.
- Provide details of previous solar or electrical work if available.
- Keep relevant documents available, such as existing solar installation paperwork.
- Ask questions about the proposed panel location and equipment.
You do not normally need to prepare the roof yourself. The installer should explain if additional access equipment or specialist inspections are required.
Why the Installer Matters
A good solar survey should produce more than a simple “yes” or “no”.
The information collected should contribute to a properly designed installation that considers the property’s characteristics, electrical system, expected generation and applicable standards.
ECO4 measures are subject to quality and compliance requirements, and Ofgem states that ECO4 measures generally need to be delivered by TrustMark Registered Businesses. Relevant technologies may also need to meet MCS requirements.
The quality of the installation can affect:
- System performance
- Reliability
- Safety
- Long-term maintenance
- Warranty arrangements
- Customer satisfaction
An installer should be willing to explain the proposed design rather than simply asking you to accept a standard package.
ECO4 Solar Survey: What Should You Ask?
Before installation, consider asking:
- How many panels are proposed?
- What is the system capacity in kWp?
- Which roof areas will be used?
- Has shading been considered?
- Where will the inverter be installed?
- What happens if roof repairs are required?
- What warranty applies?
- Who will complete the installation?
- What documentation will I receive?
- Is the installation MCS certified where required?
- Are there any additional costs I need to know about?
These questions can help you understand exactly what is being proposed.
Frequently asked questions (FAQs)
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An ECO4 solar suitability survey is designed to establish whether solar PV can be installed safely and effectively at your property.
The assessor considers much more than roof size. Roof condition, available space, orientation, inclination, shading, electrical arrangements, equipment locations and access can all influence the final design.
A thorough survey also gives you an opportunity to understand the proposed system before installation begins.
If you are considering ECO4 solar, the best approach is to choose an installer that can clearly explain the survey findings, proposed system, applicable standards and what happens next.
Simple Green Energy can help homeowners understand whether their property may be suitable for an ECO4 solar installation. Contact our team to discuss your property and arrange an assessment.
