Is my roof suitable for solar panels? The honest answer before the survey

Right after the grant question comes the roof question. Most callers ask it in some form — “will it even work on my roof?” — and it’s tempting to guess from the sound of their address. Don’t. Most of it genuinely can’t be answered without eyes on the roof, but the parts that can be answered on the phone are worth knowing cold, because they rule almost nobody out.

“Does my roof have to face south?”

No, and this is the single most common misconception on the call. SEAI’s own guidance is that the largest solar gain comes from a south-facing roof tilted 35–40 degrees — but southeast or southwest-facing roofs still produce roughly 95% of that output, and east or west-facing roofs still produce roughly 80–85%. North-facing is the real exception, not east/west. Tell callers this straight: unless their roof faces directly north, orientation almost never rules a job out on its own — it changes the system size needed to hit a given output, which is survey territory, not a phone-call estimate.

“Is my roof too steep, or not steep enough?”

Almost never an issue in Ireland. Most Irish pitched roofs already sit somewhere in the 30–45 degree range, close enough to the ideal tilt that panels mounted flush to the roof need no extra framing. The difference in annual output between a 20-degree and a 45-degree pitch is small — pitch is rarely the thing that decides a job either way, unless the roof is genuinely flat or unusually steep, both of which an installer can hear about on the phone but only judge properly in person.

“What actually stops a roof from working?”

Shading, more than orientation or pitch. A chimney, a dormer, a neighbour’s extension, or a mature tree can cut a system’s real-world output far more than a few degrees of the “wrong” direction — and shading is exactly the kind of thing that’s impossible to judge from a phone call or a satellite photo. This is the honest line to give a caller: nothing about their roof can be ruled in or ruled out for certain until someone measures it in person, which is what the free survey is actually for.

“Do I need planning permission?”

For most homes, no. Rooftop solar panels on an ordinary house have counted as exempted development since October 2022, under the Planning and Development Act 2000 (Exempted Development) Regulations of that year — meaning no planning application is needed as long as the panels don’t project more than 15cm above the roof surface and don’t extend above the ridge line. The exemption doesn’t apply to Protected Structures, homes in an Architectural Conservation Area, or sites inside a Solar Safeguarding Zone (mostly land near airports and aerodromes, covered by a companion 2022 regulation) — a short, specific list rather than a general grey area. This is well-corroborated across independent sources, including two Irish law firms citing the exact statutory instruments, though this session couldn’t reach gov.ie or SEAI directly to confirm the wording first-hand, so treat it as a strong steer rather than legal advice for an edge case.

The honest bottom line

On the phone, an installer can rule almost nothing in or out for certain — and shouldn’t try to. What a good call can do is remove the myths (south-only, steep-only, permission-required) that stop people from booking a survey in the first place, then get the free survey booked while the roof, the bill, and the grant question are all still fresh in the caller’s mind. That’s the exact shape of qualification we’ve built into Nula: she asks about the roof, the bills, and the grant, gives the honest general picture above, and books the survey rather than guessing at a number she can’t actually see.