How Is Ber Rating Calculated

Calculate your Building Energy Rating (BER) based on your property’s characteristics. This tool provides an estimate of your potential BER rating and energy performance.

A Building Energy Rating (BER) is an indicator of your home’s energy efficiency, rated on a scale from A to G. An A-rated home is the most energy-efficient, while a G-rated home is the least efficient. Understanding how BER ratings are calculated can help you improve your home’s energy performance and reduce your energy bills.

What is a BER Certificate?

A BER certificate is a document that shows the energy performance of a building. It includes:

• The energy rating (A-G scale)
• Primary energy use in kWh/m²/year
• CO₂ emissions in kgCO₂/m²/year
• Recommendations for improvement

In Ireland, a BER certificate is required when:

• Selling or renting a property
• Constructing a new building
• Undertaking major renovations

How BER Ratings Are Calculated

The BER rating is calculated using the Dwelling Energy Assessment Procedure (DEAP), which is Ireland’s official methodology for assessing residential energy performance. The calculation considers:

1. Building Fabric (40% of score)

The thermal performance of the building’s structure:

• Wall insulation (U-values of walls)
• Roof insulation (U-values of roof)
• Floor insulation (ground floor U-values)
• Windows and doors (U-values and solar gain)
• Thermal bridging (heat loss at junctions)
• Air tightness (measured in air changes per hour)

Building Element	Poor (G Rating)	Average (D Rating)	Good (B Rating)	Excellent (A Rating)
Wall U-value (W/m²K)	≥1.6	0.45-0.6	0.27-0.3	≤0.21
Roof U-value (W/m²K)	≥0.35	0.2-0.25	0.13-0.16	≤0.13
Window U-value (W/m²K)	≥3.0 (single glazing)	2.0-2.8 (old double)	1.2-1.6 (new double)	≤1.0 (triple glazing)

2. Heating System (30% of score)

The efficiency of your heating system and controls:

• Boiler efficiency (SEDBUK rating for gas/oil)
• Heating controls (thermostats, timers, TRVs)
• Heat distribution (radiators/underfloor)
• Hot water system (cylinders, insulation)

3. Ventilation (10% of score)

How air moves through the building:

• Natural ventilation (windows, trickle vents)
• Mechanical extract (bathroom/kitchen fans)
• Heat recovery (MVHR systems)

4. Lighting (5% of score)

The type and efficiency of lighting:

• Incandescent bulbs (poor)
• Halogen bulbs (average)
• CFL bulbs (good)
• LED bulbs (excellent)

5. Renewable Energy (15% of score)

Contributions from renewable sources:

• Solar thermal (water heating)
• Solar PV (electricity generation)
• Heat pumps (air/ground source)
• Wind turbines (small-scale)

BER Rating Scale Explained

The BER scale ranges from A1 (most efficient) to G (least efficient). Here’s what each rating typically means:

Rating	Primary Energy (kWh/m²/year)	CO₂ Emissions (kg/m²/year)	Typical Home Characteristics
A1	<25	<5	New build with heat pump, excellent insulation, solar PV, MVHR
A2	25-50	5-10	New build with heat pump, very good insulation, some renewables
A3	50-75	10-15	New build with gas boiler, excellent insulation, solar thermal
B1	75-100	15-20	Modern home (post-2011) with good insulation and efficient heating
B2	100-125	20-25	2005-2010 build with decent insulation and condensing boiler
B3	125-150	25-30	1990s-2004 build with some insulation upgrades
C1	150-175	30-35	1980s build with partial insulation and older boiler
C2	175-200	35-40	1970s build with minimal insulation and old heating system
C3	200-225	40-45	Pre-1970s build with no insulation and very old boiler
D1	225-250	45-50	Old property with single glazing and no insulation
D2	250-300	50-60	Very old property with solid walls and poor heating
E-F-G	300+	60+	Historic properties with no energy efficiency measures

How to Improve Your BER Rating

Improving your BER rating can increase your home’s value, reduce energy bills, and lower your carbon footprint. Here are the most effective upgrades, ranked by impact:

1. Insulation Upgrades
   • Attic insulation (most cost-effective, can improve rating by 1-2 grades)
   • Cavity wall insulation (for homes built after 1920s with cavity walls)
   • External wall insulation (for solid wall homes, more expensive but very effective)
   • Floor insulation (especially for ground floors)
2. Window Upgrades
   • Replace single glazing with A-rated double or triple glazing
   • Ensure windows are properly sealed to reduce drafts
   • Consider low-emissivity (low-E) glass for better heat retention
3. Heating System Upgrades
   • Replace old boilers with A-rated condensing boilers (can improve rating by 1 grade)
   • Install heat pumps (air-source or ground-source) for highest efficiency
   • Upgrade heating controls to smart thermostats and TRVs
   • Improve hot water cylinder insulation
4. Renewable Energy Systems
   • Solar PV panels (can improve rating by 1-2 grades)
   • Solar thermal for water heating
   • Small wind turbines (where suitable)
5. Ventilation Improvements
   • Install mechanical ventilation with heat recovery (MVHR)
   • Seal air leaks while ensuring adequate ventilation
   • Install extractor fans in bathrooms/kitchens if missing
6. Lighting Upgrades
   • Replace all bulbs with LED lighting
   • Install motion sensors for outdoor lighting

Common BER Rating Myths Debunked

There are many misconceptions about BER ratings. Here are some common myths and the truth behind them:

Myth 1: “A BER certificate tells you how much your energy bills will be”

Reality: A BER certificate shows the potential energy performance based on standard occupancy assumptions. Actual bills depend on:

• How many people live in the home
• Your heating patterns and temperature preferences
• Energy prices (which fluctuate)
• How well you maintain your heating system

Myth 2: “You can’t get an A rating with a gas boiler”

Reality: While heat pumps make A ratings easier to achieve, it’s possible to get an A rating with a gas boiler if:

• The home has exceptional insulation (U-values ≤0.15)
• The boiler is A-rated condensing with weather compensation
• There’s solar thermal for water heating
• The home has MVHR ventilation
• Lighting is 100% LED

Myth 3: “Older homes can’t get good BER ratings”

Reality: While older homes start with disadvantages, many have achieved B and even A ratings through deep retrofits. For example:

• A 19th-century cottage in Cork achieved a B2 after external wall insulation, heat pump installation, and solar PV
• A 1970s bungalow in Dublin went from G to B1 with cavity wall insulation, attic insulation, new windows, and a heat pump
• A Georgian townhouse in Galway improved from F to C1 with internal wall insulation and underfloor heating

Myth 4: “BER assessors are inconsistent”

Reality: While there can be minor variations (usually ±5 kWh/m²/year), BER assessors follow strict DEAP methodology. The main reasons for different ratings on the same property are:

• Different assumptions about unmeasurable factors (e.g., air tightness if not tested)
• Updates to the property between assessments
• Different versions of the DEAP software (updated annually)

BER Rating and Property Value

Research shows that BER ratings significantly impact property values and marketability:

• A 2022 SEAI study found that improving from a D to a B rating can increase property value by 5-12%
• Homes with A or B ratings sell 20% faster than similar homes with D-G ratings (Daft.ie 2023 report)
• Rental properties with BER ratings of B or higher can command 8-15% higher rents (CSO data)
• Since 2023, mortgage lenders offer better rates for homes with BER ratings of B or higher

The payback period for BER improvements varies:

Improvement	Typical Cost	Annual Savings	Payback Period	BER Improvement
Attic insulation (top-up to 300mm)	€800-€1,500	€200-€400	3-7 years	1-2 grades
Cavity wall insulation	€1,200-€2,500	€300-€600	4-8 years	1-3 grades
External wall insulation	€10,000-€20,000	€800-€1,500	10-20 years	2-4 grades
New A-rated windows	€8,000-€15,000	€300-€700	15-30 years	1 grade
Heat pump (replacing oil boiler)	€12,000-€20,000	€1,000-€2,000	8-15 years	2-3 grades
Solar PV (4kW system)	€6,000-€9,000	€800-€1,500	5-10 years	1-2 grades

BER Rating and Climate Change

Ireland has committed to reducing greenhouse gas emissions by 51% by 2030 under the Climate Action Plan. Improving BER ratings plays a crucial role:

• The residential sector accounts for 25% of Ireland’s energy-related CO₂ emissions (SEAI 2023)
• Upgrading all homes from D to B rating would reduce national emissions by 3-5 million tonnes CO₂/year
• The government’s Climate Action Plan targets:
• 500,000 home retrofits by 2030
• 400,000 heat pump installations by 2030
• All new homes to be Nearly Zero Energy Buildings (NZEB) since 2019

Grants are available to help with upgrades:

• SEAI Home Energy Grants (up to €25,000 for deep retrofits)
• Warmer Homes Scheme (free upgrades for eligible households)
• Local authority grants (varies by county)
• 0% green loans from some banks for energy upgrades

How to Get a BER Certificate

To get an official BER certificate:

1. Find a registered BER assessor through the National BER Register
2. Prepare your home by gathering information about:
• Year of construction
• Insulation types and thicknesses
• Heating system details (boiler make/model)
• Window types and ages
• Any renewable energy systems
3. Schedule the assessment (takes 1-2 hours)
4. The assessor will:
• Measure the property
• Inspect insulation, windows, heating system
• Take photographs for the report
• Input data into DEAP software
5. Receive your certificate (usually within 2-3 days)
6. Implement recommendations to improve your rating if desired

Cost: €150-€300 depending on property size and location

Valid for: 10 years (unless significant changes are made to the property)

Future of BER Ratings in Ireland

The BER system is evolving to meet climate targets:

• 2025: Minimum BER requirement for rental properties will increase from E to D
• 2028: Minimum BER requirement for rental properties will increase to C
• 2030: All homes will need a BER of B2 or higher to qualify for certain grants
• New DEAP 4.0: Updated calculation methodology being introduced in 2024 with:
• Stricter requirements for heat pumps
• More accurate modeling of heat loss
• Updated primary energy factors
• Better accounting for renewable energy systems
• Smart Readiness Indicator (SRI): New EU requirement being integrated into BER certificates to show how “smart” a home is in terms of energy management

Frequently Asked Questions

How long does a BER assessment take?

The on-site assessment typically takes 1-2 hours for an average home. The assessor will then spend another 1-2 hours entering data and generating the certificate.

Can I fail a BER assessment?

No, there’s no pass/fail. The BER certificate simply rates your home’s energy performance on the A-G scale and provides recommendations for improvement.

How accurate is a BER certificate?

BER certificates are based on standardized assumptions about occupancy and energy use. The actual energy consumption can vary by ±20% depending on:

• Number of occupants
• Heating patterns and temperature preferences
• Appliance usage
• Ventilation habits

Does a BER certificate include recommendations?

Yes, every BER certificate includes a list of recommended improvements, typically including:

• Insulation upgrades (attic, walls, floor)
• Heating system upgrades
• Window replacements
• Renewable energy options
• Ventilation improvements

The recommendations are prioritized by cost-effectiveness and potential energy savings.

Can I do a BER assessment myself?

No, BER assessments must be carried out by a registered BER assessor. However, you can use online tools (like the calculator above) to get an estimate of your home’s performance.

How often should I get a new BER certificate?

You only need a new BER certificate when:

• Selling or renting your property
• You’ve made significant energy efficiency improvements
• Your current certificate is more than 10 years old

However, getting a new assessment after upgrades can help you:

• Track your progress
• Qualify for certain grants
• Increase your property value

Does a BER certificate affect my home insurance?

Currently, BER ratings don’t directly affect home insurance premiums in Ireland. However:

• Some insurers offer discounts for homes with better BER ratings (5-10% in some cases)
• Homes with poor BER ratings may be at higher risk of damp and mold, which could affect claims
• As climate policies evolve, insurance companies may start using BER ratings more prominently in risk assessments

Conclusion

Understanding how BER ratings are calculated empowers you to make informed decisions about your home’s energy performance. Whether you’re looking to reduce energy bills, increase your property value, or contribute to Ireland’s climate goals, improving your BER rating is a smart investment.

Key takeaways:

• BER ratings are calculated using the DEAP methodology, considering building fabric, heating systems, ventilation, lighting, and renewable energy
• The scale runs from A1 (most efficient) to G (least efficient), with most Irish homes currently in the C-D range
• Improving insulation, upgrading heating systems, and adding renewables are the most effective ways to boost your rating
• Better BER ratings can increase property values by 5-12% and reduce energy bills by 30-70%
• Government grants of up to €25,000 are available to help with energy upgrades
• New regulations will require higher minimum BER ratings for rental properties in 2025 and 2028

Use the calculator at the top of this page to estimate your current BER rating and explore potential improvements. For an official assessment, contact a registered BER assessor through the SEAI’s National BER Register.