As interest in solar energy surges across Ireland, one of the most common questions homeowners ask is: How much solar power do I actually need? The answer depends on your household’s electricity usage, roof space, and your goals for savings and sustainability. But most homes will need a 3–6 kWp system.
Whether you’re in Dublin, Cork, Galway, or anywhere in between, the answer depends on your energy usage, roof space, orientation, and budget. But don’t worry. WattCharger is here to help you break it down clearly and practically.
Let’s explore how to calculate your ideal solar system size using real Irish data, including how many solar panels the average home might need and what tools (like a kWp calculator) can help you make the right decision.
To understand how much solar power you need, you first need to know what kWp means.
kWp stands for kilowatt-peak, and it’s a measure of the maximum power output of a solar panel system under ideal conditions. A 4 kWp system, for example, can produce up to 4 kilowatts of electricity per hour during peak sunshine.
💡 Need a deeper dive into kWp? Check out our article: What is kWp? Understanding the Key to Solar Panel Performance in Ireland
Several factors influence how many panels and how much power you’ll need:
1. Your Current Electricity Usage
Grab your most recent electricity bill and check your annual consumption in kWh (kilowatt-hours). The average Irish home uses around 4,200 kWh per year, but yours might be higher if you use an EV charger, heat pump, or work from home.
2. Your Location and Sunlight Access
Solar panels still work on cloudy days, but your region matters. Homes in Cork or Kerry, for example, may get slightly less usable sunlight than homes in Wexford or Dublin due to average cloud cover. However, Ireland averages 950–1,100 sun hours per year, so solar remains a strong investment nationwide.
3. Roof Size and Orientation
A south-facing roof is ideal. You’ll also need to know how much space you have. A typical panel is about 1.7 m², and you’ll need 3–5 panels per kWp installed.
4. Whether You Want Battery Storage
Battery systems can store unused solar energy, reducing reliance on the grid and increasing your return on investment, especially useful during the darker winter months.
You can use a rough rule of thumb to get started:
Annual kWh usage ÷ 1,000 = Ideal kWp
So, if your household uses 4,500 kWh per year:
4,500 ÷ 1,000 = 4.5 kWp
That means you’d ideally install a system that can produce up to 4.5 kWp, or around 10–12 solar panels, depending on their efficiency. Read our complete guide to understanding kWp here
📐 Tip: Want a precise number? Contact us now and we will calculate your needs based on your home size, electricity usage, and roof details.
Here’s what most homeowners in Ireland typically install:
Remember, more panels don’t always mean better value. It’s about matching the system to your needs, not just filling the roof.
Yes. With the Clean Export Guarantee (CEG) scheme, you can sell unused electricity back to the grid and earn a feed-in tariff from your supplier. If your system is producing more than your home needs, especially during summer, this is a great way to get extra return on your investment.
🔎 Read more: Updated Guide to Feed-in Tariffs in Ireland for 2025
Don’t forget that the Sustainable Energy Authority of Ireland (SEAI) offers grants of up to €1,800 to help cover the cost of solar PV installations. This can significantly reduce your out-of-pocket expense and improve your payback time.
Here’s a summary to help you decide:
Need help putting it all together? WattCharger can walk you through every step. From sizing and system design to installation and grant applications.
We’ve helped hundreds of Irish homeowners find the right-sized solar setup. No fluff, no pressure, just real insights based on your needs.
📞 Contact WattCharger today for a free, no-obligation quote tailored to your roof, usage, and budget.