Understanding the Building Energy Rating of Irish Homes
Author: Charlotte Cuffe, Data Scientist at Gamma
In a world where energy efficiency and climate action are increasingly urgent, understanding the building energy rating (BER) of your home isn’t just helpful—it’s essential. For Irish homeowners, buyers, and policy leaders alike, this rating plays a pivotal role in property value, energy costs, and sustainability goals.
In this article, you’ll discover what the building energy rating is, how it’s calculated, and how Gamma Labs is using innovative tools like BERWOW to help you make smarter, greener decisions.
What Is a Building Energy Rating?
A building energy rating (BER) measures the energy performance of a property on a scale from A1 (most efficient) to G (least efficient). It represents the estimated primary energy use per square metre per year (kWh/m²/year) for heating, lighting, ventilation, and hot water.
A BER certificate is legally required when selling or renting a home. But even if you’re staying put, your BER gives you a clear picture of your home’s energy performance—and where it can improve.
How Is the Building Energy Rating Calculated?
The Sustainable Energy Authority of Ireland (SEAI) manages the BER system using the Dwelling Energy Assessment Procedure (DEAP). After surveying your home, a certified assessor calculates energy use and CO₂ emissions based on:
- Building materials and insulation levels
- Heating system efficiency and fuel type
- Airtightness and ventilation
- Glazing and solar gain
- Integration of renewable energy sources
At the core of this process is a key number: The primary energy required to run the home for a year, expressed in kilowatt-hours per square metre per year (kWh/m²/year).
This number determines the building energy rating and is grouped into 15 bands—from A1 (most efficient) to G (least efficient). Homes that require less than 25 kWh/m²/year receive an A1 rating. In some cases, A1-rated homes generate more energy than they consume, even contributing power back to the national grid.
See the diagram below for a breakdown of how BER bands are structured and calculated.
Your Home’s BER
How to Obtain Your BER Certificate
If your property doesn’t already have a BER certificate—or if it has expired (certificates are valid for 10 years)—you’ll need to hire a registered BER assessor. You can:
- Check if a BER exists for your property by visiting the National BER Register on SEAI’s website
- Download your certificate and advisory report using your BER number or MPRN (found on your electricity bill)
Understanding Your BER Certificate
Your BER certificate includes several key data points:
- Address, BER number, and issue date (valid for 10 years)
- Primary energy use (kWh/m²/year) – the lower the number, the more efficient the home
- BER rating band – calculated from the primary energy figure
- Greenhouse gas emissions (kg CO₂/m²/year) – lower emissions reflect a smaller climate impact
Each part of the certificate gives insight into both energy use and environmental performance, helping you make data-informed decisions about your home.
✅ Explore your home’s rating with BERWOW
What Is a Good Building Energy Rating?
A B2 rating or better is widely considered a strong result for residential homes in Ireland. It indicates effective insulation, modern heating systems, and overall energy efficiency.
In fact, the Irish government aims to bring 500,000 homes to a B2 rating by 2030 as part of its national Climate Action Plan.
Achieving a B2 building energy rating delivers multiple advantages:
- Lower heating bills and energy costs
- Reduced carbon footprint
- Higher property resale value
- Eligibility for green mortgages with lower interest rates
- Access to government grants, which often require a B2 rating as a condition
- A more comfortable and less draughty home with an improved living experience.
Many homeowners actively work toward achieving a B2 rating to maximise energy savings and future-proof their property.
Why the Building Energy Rating Matters More Than Ever
A higher building energy rating isn’t just good for the environment—it’s good for your wallet. Homes with an A or B rating tend to:
- Sell faster and for higher prices
- Qualify for more green energy grants
- Require less spending on heating and maintenance
- Support Ireland’s national climate targets
At Gamma Labs, we’ve analysed hundreds of thousands of BER records to uncover patterns, regional gaps, and upgrade opportunities. Our data-driven tools empower homeowners, local authorities, and energy partners with real-time insights—not static reports.
👉 Download the BER Insights Whitepaper to explore national energy trends.
How to Improve Your Building Energy Rating
If your home has a low energy rating, don’t worry. Many improvements can make a meaningful difference:
- Insulation: Upgrade insulation in the attic, walls, and floors
- Glazing: Switch to double or triple-glazed windows
- Heating: Install a heat pump or modern boiler
- Renewables: Add renewable technologies such as solar PV or solar thermal systems
- Airtightness & Ventilation: Eliminate drafts and optimise airflow
Also, the Sustainable Energy Authority of Ireland (SEAI) offers several grant schemes to help fund energy upgrades. These include Home Energy Grants, One-Stop Shop Services, and Community Energy Grants.
Every BER assessment comes with an Advisory Report that outlines specific, recommended improvements. This report is your roadmap for making cost-effective, impactful changes.
BERWOW and Data Intelligence
Your building energy rating is more than a number—it’s a roadmap to energy efficiency, cost savings, and climate responsibility.
At Gamma Labs, through our BERWOW platform, we help make that roadmap clear and actionable with advanced tools and expert insights, such as:
- Retrieve your home’s BER data using a BER certificate number or MPRN.
- Receive a customized energy efficiency plan tailored to your property.
- Improve your BER rating with step-by-step retrofit recommendations.
- Calculate costs, available grants, and expected energy savings.
- Book a free consultation.
BERWOW is used by major financial and energy companies to help customers enhance their home energy efficiency. Notable partnerships include:
- Bank of Ireland – Offers an online BERWOW tool to help homeowners explore retrofit options. Try it here: BERWOW at BOI
- SSE Airtricity – Integrates BERWOW into its sustainability hub, providing customers with energy-saving insights. Try it here: SSE BERWOW
Looking Ahead: Structured Retrofits with Renovation Passports
While the BER provides a snapshot of your home’s current energy performance, what if you could see a clear roadmap for improving it over time?
That’s where Building Renovation Passports (BRPs) come in.
As a key partner in the European One Click Reno (OCR) Project, Gamma Labs is helping shape the next evolution in home energy planning: the Building Renovation Passport.
This initiative is designed to:
- Develop digital tools to simplify the home renovation process.
- Provide a step-by-step renovation roadmap tailored to each home.
- Improve access to grants and financing for sustainable home upgrades.
Building Renovation Passports will soon be introduced in Ireland, offering homeowners a structured plan for long-term, staged retrofits that enhance energy efficiency and reduce carbon footprints.
Final Thoughts
Your building energy rating is more than a legal requirement—it’s a tool to enhance comfort, cut costs, and reduce your environmental impact.
With the right insights, tools, and support, every Irish homeowner can take meaningful steps toward a greener, more efficient future.
