Typical Solar Panel System Sizes and Output (2026)
Typical solar PV system sizes in Ireland, including panel counts, annual generation, roof-space requirements, household demand and oversizing considerations.
Most common domestic system: 4–5 kWp
How Solar Systems Are Sized
Domestic solar PV is usually sized around available roof space, household electricity demand, budget and grant eligibility.
Most Irish installations fall between 3–6 kWp and use around 8–16 panels.
Modern residential panels are typically rated at around 400–450 W each.
Panel Count & System Size
8 panels: ~3.2 kWp
10 panels: ~4.0 kWp
12 panels: ~4.8 kWp
16 panels: ~6.4 kWp
Household Sizing & Roof Space
Typical Household Match
3 kWp: small household
4 kWp: typical semi-detached
5 kWp: medium demand
6 kWp: larger household / EV
Roof Area
3 kWp: ~15 m²
4 kWp: ~19 m²
5 kWp: ~26 m²
6 kWp: ~34 m²
Annual Output & Household Demand
| System | Typical Annual Generation | Typical Match |
|---|---|---|
| 3 kWp | 2,700–3,000 kWh | Apartment / small home |
| 4 kWp | 3,600–4,200 kWh | Typical semi-detached |
| 5 kWp | 4,500–5,200 kWh | Medium demand |
| 6 kWp | 5,400–6,200 kWh | Large household / EV |
Orientation & Seasonal Generation
South-facing roofs provide the highest annual output, while east–west systems typically achieve around 80–90% of south-facing production.
Most solar generation arrives between April and September.
The source estimates roughly 40–45% of annual output in summer and only 5–10% in winter.
Example 4 kWp System & Export
| Item | Example |
|---|---|
| Panel count | 10 |
| System size | ~4 kWp |
| Annual generation | ~4,000 kWh |
| Example household use | 4,200 kWh/year |
| Typical exported share | 30–70% depending on usage |
A system can generate close to annual household consumption without eliminating imports, because solar generation and demand occur at different times.
Oversizing & Future Demand
Why Oversize
Future EV charging
Heat-pump installation
Battery integration
Trade-Off
Larger systems may export more electricity
Export tariffs provide some return
Roof space and grant cap still matter
Typical 2026 Summary
Most common size: 4–5 kWp
Most common panel count: 10–14
Typical annual generation: 3,500–5,500 kWh
Summary
Most Irish homes install around 4–5 kWp of solar PV, typically 10–14 panels.
Domestic systems generally range from 3–6 kWp and generate about 3,500–5,500 kWh/year.
Roof space and household electricity demand should determine system size, not panel count alone.
Other resources:
Solar Panel Cost After SEAI Grant
Solar Panel Battery Add-On Cost
Installation Process Explained