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How Many Solar Panels Do I Need?
How many solar panels do I need?
PICTURE: How many solar panels do I need?
MAY 15 2024
It's no secret that solar power is getting more popular in Ireland because it's eco-friendly, cost-effective, and flexible.
The 2022 Census revealed that one in four homes use renewable energy, with over 100,000 homes in the country using solar panels. However, installing a solar panel PV system that can power your appliances all year long requires understanding how PV systems work. You can estimate the number of solar panels you need for your solar PV system by using a simple formula or rough estimate based on a few factors listed below. Your energy consumption needs will determine which kind of panels you need.

In this blog, we'll explain how to calculate the number of panels needed, recommended panel sizes, and how to get solar panel grants in Ireland.

Table of Contents:
  • Factors that determine how many solar panels you need
  • How to calculate how many solar panels I need
  • What size solar panels do I need in Ireland
  • The future of solar panels in Ireland
  • How to access solar panel grants 
Factors that determine the number of solar panels you need

So, how many solar panels do you need in Ireland? Every household and business will differ so there's no one-size-fits-all answer. In the end, you'll want to consult energy experts like us to help you make the best decision. There are a few factors you can use to figure out what kind of Solar PV system your property needs.   

Daily energy consumption 
The number of solar panels you need depends on your daily energy consumption. This includes calculating the total energy usage of all appliances, lighting, and electrical devices in your home. By looking at your energy bills and usage patterns, you can estimate the amount of electricity you need to generate with solar.

The orientation of your house
The orientation of a house is important for the efficiency of solar panels. Ideally, panels should face south in the Northern Hemisphere to receive the most sunlight. If your roof doesn't face south, adjustments can be made to panel placement and angle for better sunlight exposure.

Your roof dimensions 
The size, shape, and slope of your rooftop play a key role in finding out how many solar panels you can install and how efficiently they can generate energy. The bigger the roof, the more solar panels you can fit, resulting in a boost in energy production.

Panel efficiency 
Solar panel efficiency is the amount of sunlight that can be turned into electricity. Panels with higher efficiency make more electricity per square meter. Consider efficiency ratings when deciding how many panels you need.

Wattage/Power rating of the panel 
Solar panels have different wattages (250-550 watts) which determine their power output. Higher-wattage panels produce more electricity. Consider both wattage and efficiency when calculating the number of panels needed to ensure the panels perform best.

Your local climate affects how well solar panels work. More sun means more electricity, while clouds or shading reduce efficiency. Solar panels still generate energy on cloudy days, but you will need to take Ireland's weather into account when estimating solar panel output.

How to calculate how many solar panels I need? 

One way to figure out how many solar panels you need for your home or business is to use the formula below. To figure out how many panels you need, divide your daily energy consumption by average daily sunlight hours and panel wattage.


While our weather may not always be that good, Ireland still produces a significant amount of sunlight needed to produce solar energy. Ireland’s average sunlight hours range from 1,200 to 1,400 hours  per year, depending on which county you are in. 

For example, a 3-bedroom house in Dublin with an average daily usage of 20 kilowatt-hours (kWh) and a roof area of 50 square meters available for solar panels. Dublin gets approximately 1,300 hours of sunlight per year, one 550-watt solar panel can generate about 2.2 kWh of electricity per day. To meet a daily consumption of 20 kWh, a professional solar installer may suggest that around 9-10 solar panels would be needed, typically installed as whole units depending on budget and energy needs. 

It's easy to figure out the right number of solar panels for your home with Energia. Our team conducts a site assessment taking into account all of these factors to come up with a reliable estimate of the number of panels you'll need. We'll help you figure out the perfect solar panel solution for your home by giving you a free quote.


What size solar system do I need in Ireland? 

The size of your solar system in Ireland depends on your energy needs and roof space. Residential systems range from 1.5 kW to 5 kW, while larger systems are for detached houses or commercial use. We recommend that you talk with to Energia to find the right size for you. 

The future of solar panels in Ireland 

In 2022, the government launched The Climate Action Plan which outlines the steps Ireland can take to address the climate crisis by prioritising climate solutions. As the country strives to reduce its carbon footprint and transition to clean energy sources, solar power offers a sustainable solution for generating electricity and broadening Ireland’s energy mix. Government incentives and grants make solar panel installation accessible and affordable. Solar panel installations are expected to become more common throughout Irish homes and businesses in the coming years. 

How to access solar panel grants 

To get a solar electricity grant, pick a registered one stop shop like Energia, and we will take care of the rest, including the grant application and providing a BER post- installation. We will also discount the grant value up front so that you don’t have to wait around for payback.  In addition, Our new smart solar bundle offers customers on any Energia Smart tariff a saving of €750 on solar panel installation as well as a 24 cent microgeneration export rate. Get in touch with us today and we can best on how many solar panels your property needs.

Want to learn more?
Read the rest of our solar guides!