The 29 Best Counties in Ireland for Commercial Solar (Ranked by Data)

Irish solar installers are prospecting blind. There's no single authoritative source for where the commercial solar opportunity actually is — no ranked list, no territory map, no way to know whether Galway is twice the opportunity of Limerick or half of it. Most installers rely on word of mouth, existing relationships, driving routes they already know, or gut feel built from years on the road. That's fine when the market is thin. It's a real competitive disadvantage now that the market isn't.

VantageHQ processed 156,092 commercial buildings across the Republic of Ireland through a four-layer analysis — Tailte Éireann property records, ArcGIS satellite imagery, PVGIS irradiance data, and Gemini Vision AI roof assessment — to produce this ranking. Every county, scored by the same methodology, sorted by the metric that matters for installers: how many buildings in this territory are genuinely viable solar prospects.

How we ranked the counties

Not every commercial building is a solar prospect. A warehouse with north-facing skylights and a heavily shaded roof is a waste of your time. We applied three filters to strip out buildings that won't convert, leaving only what we call ICP buildings — Ideal Customer Profile.

A building qualifies as an ICP if it passes all three gates:

• Roof area ≥ 100m² — derived from Tailte Éireann floor area records as a proxy for usable roof space. Smaller than this and a commercial system doesn't make economic sense.
• Irradiance ≥ 900 kWh/m²/year — sourced from PVGIS, the EU's authoritative solar resource database. Ireland's south and east coasts clear this threshold comfortably; the north-west does not in every case.
• Viable roof confirmed by AI assessment — Gemini Vision AI runs a three-pass analysis on each building's satellite imagery: roof pitch and orientation, shading obstructions, and structural suitability confidence score. Only buildings that pass all three passes are included.

The result is a count of genuinely solar-viable commercial buildings per county — not gross property numbers, not planning data, not a rough estimate. Each ICP building is a legitimate prospecting target.

The full ranking — all 29 counties

Sorted by ICP count, highest to lowest. Tier badges reflect the overall opportunity rating. Counties marked as Claimed have been contracted to an exclusive installer.

What the data reveals

1. Dublin is three separate territories, not one

The instinct is to think of Dublin as a single market — and to therefore assume it's already saturated. The data tells a different story. Dublin City, South Dublin, and Fingal are three distinct geographic territories with 1,680, 1,295, and 1,120 ICP buildings respectively. Together they account for over 4,000 viable prospects — but an installer working the south-west of the county isn't genuinely competing with one working the north. An exclusive territory in any one of the three Dublin areas is its own coherent commercial opportunity. The mistake is treating "Dublin" as a single slot already taken.

2. The hidden-gem counties: Galway and Limerick

Raw ICP count isn't the only signal. Conversion efficiency — ICPs as a share of total buildings — matters too. Limerick has a 14.2% ICP conversion rate (620 ICPs from 4,380 buildings), compared to Dublin City's 13.1% (1,680 from 12,850). That means a higher proportion of the buildings you approach in Limerick will be genuinely viable — less wasted prospecting, better hit rates. Galway runs similarly. Both counties are also major commercial hubs with a concentration of manufacturing, logistics, and agri-processing — sectors with large flat roofs, high energy bills, and owner-operators who control the capex decision. Neither is an obvious first choice when you look at raw market size. Both reward the installer who gets there with data.

3. The midlands gap is real

Longford (980 buildings, 140 ICPs) and Leitrim (780 buildings, 110 ICPs) sit at the bottom of the table and not by accident. These are genuinely thin commercial markets — smaller total building stock, more dispersed geography, weaker irradiance averages. The Standard-tier designation reflects this honestly. There are 110 viable solar prospects in Leitrim; that's a small pipeline for a full-time commercial installer. An installer already working that geography can supplement their residential pipeline with it. As a standalone commercial territory, it doesn't justify the exclusivity investment.

4. Gold and Silver tiers are moving

Two counties are already off the table. Kildare (685 ICPs, Gold tier) is contracted to Solarstream. Meath (560 ICPs, Silver tier) is also claimed. Six of the eight Gold-tier counties are still available as of this writing. That number will not stay static — the commercial solar opportunity is visible to every installer who reads the same industry reports, and data-backed prospecting is becoming table stakes rather than a differentiator.

The bottom line

156,092 commercial buildings have been processed through four layers of analysis. Each one has a viability score, a system size estimate, an annual generation projection, and — where available — decision-maker contact data attached to it. The counties above are not guesses or market reports extrapolated from census data. They're a direct count of the buildings worth approaching in each territory, ranked by that count.

The data exists. The question is whether you're using it before your competitor does — or whether you're still driving routes you already know, hoping a referral lands from a job you finished six months ago.