What to Expect During a Solar Site Survey (Philippines)

A solar site survey is the installer’s in-person check of your roof, electrical panel, shading, and usage pattern before finalizing your system design. It typically takes 1 to 2 hours and happens before or right after you sign, depending on the installer. Skipping it, or working from satellite photos alone, is how systems end up undersized, poorly angled, or running into electrical panel surprises mid-installation.

What does the installer check on the roof?

This is usually the biggest part of the visit.

• Material and condition. Whether it’s metal (common on Philippine homes), concrete, or tile changes the mounting hardware needed, and any existing rust, cracks, or leaks get flagged before panels go on top of them.
• Structural strength. Whether the roof framing can support the added weight of panels and mounting rails, especially on older homes.
• Orientation and tilt. Which direction sections of the roof face and at what angle, since this affects how much sun each section actually gets.
• Usable, unshaded area. How much roof space is actually clear of vents, water tanks, and other rooftop equipment, matched against how much roof space your system needs.
• Access and mounting path. How panels and equipment would physically get onto the roof, and where the cable run to the inverter and electrical panel would go.

What does the installer check on my electrical setup?

The second major piece is your main electrical panel and existing wiring.

• Panel capacity. Whether your main breaker and busbar can handle the added solar circuit, or whether an upgrade is needed first.
• Panel condition and age. Old or overloaded panels sometimes need work done before a solar connection can be added safely.
• Meter location and accessibility, since this is where the bi-directional meter eventually goes once net metering is approved.
• Grounding and wiring condition, particularly relevant in older homes where wiring may not meet current standards.

How does shading get assessed?

The installer looks at trees, neighboring buildings, water tanks, and antennas that could cast shadows across the array at different times of day and different seasons, not just what’s shaded at the moment they’re standing there. Even partial shading on part of an array can drag down output for the whole string, depending on the inverter setup, so this step matters more than it looks. See our how shading affects solar output guide for why a small shadow can cause an outsized drop in production.

What do I need to provide?

Mostly information, not equipment.

• 3 to 6 months of recent electric bills, so the installer can confirm your usage pattern matches what was used for the initial quote.
• Roof access, including keys or coordination if it’s not straightforward to reach.
• Any history worth mentioning: past roof leaks, recent repairs, planned renovations, or known electrical issues.
• Your daytime usage pattern, since a household running aircon and appliances during the day gets more value from a given system size than one that’s empty until evening.

Does the site survey change my quote?

Often, at least a little. Initial quotes are frequently built from your bill and satellite imagery before anyone has physically checked the roof, so a site survey that finds more shading, a smaller usable roof area than expected, or an electrical panel needing upgrade work can shift the final system size and price. This is normal and part of why the site survey happens before, not after, a final contract is signed. If the numbers move a lot from the initial estimate, that’s worth discussing directly with the installer rather than assuming the original quote was accurate.

What happens after the site survey?

The installer finalizes the system design based on what they found, confirms pricing, and moves into permitting and scheduling. See our how long does solar installation take guide for what the full timeline looks like from here. If you haven’t chosen an installer yet, our how to choose a solar installer guide covers what to check before you commit to one, and the roof types and solar mounting guide goes deeper on how your specific roof material affects the mounting plan.