How to boost your Building Energy Rating (BER)
Boosting your home’s energy rating can slash your energy bills, make your house warmer and even unlock cheaper mortgage deals. Here’s how to improve your BER and save money.
What is a Building Energy Rating (BER)?
A Building Energy Rating (BER) shows the energy performance of your home and grades your home’s energy efficiency on a scale of A-G.
A-rated homes are most energy-efficient and G-rated homes are the least. The higher your BER, the lower your energy use is; for instance, an A-rated house conserves heat better so less fuel is needed to keep it warm.
When it comes to energy bills, an A-rated home will benefit from lower energy costs, whereas a G-rated home will attract high energy bills.
The BER certificate
A BER certificate is required for the majority of homes for sale or rent in Ireland and BER details must be included in advertisements when a home is on the market.
Since 2007 all new homes are required to have a BER certificate. It ensures new dwellings are built with energy-efficient designs, materials, and appliances in line with the Government’s Sustainable Energy Policy.
How do I get a copy of my BER?
Find if your home has a BER, and download the certificate and advisory report on the SEAI National BER Register. You’ll need the MPRN number from an electricity bill and the BER number.
Why is it required?
An owner must provide a BER to prospective buyers or tenants when a home is offered for sale or rent and homeowners must obtain a BER before a new home is occupied for the first time.
A BER is required on a dwelling when it is:
- Offered for sale off plans (provisional BER)
- A new dwelling for occupation
- Offered for sale or rent
- Undergoing work that requires a grant from SEAI
Exemptions apply to protected, historic structures and temporary or derelict properties.
How do you get a BER?
BERs are carried out by independent assessors registered with the Sustainable Energy Authority of Ireland (SEAI). The assessor will need between 30 minutes and an hour to do the inspection depending on the size of your home.
You can find a list of registered BER assessors at SEAI.ie. Just search in your area or check if an assessor is registered.
Finding a BER assessor
Using the SEAI’s BER assessor tool, shop around, get multiple quotes (at least three) and compare prices and information.
When dealing with assessors:
When you’ve chosen an assessor:
- Request a written agreement or contract (SEAI example here)
- Request a description of proposed services, costs and expenses
- Confirm your postal address and Eircode
- Confirm your Meter Point Reference Number (MPRN) from your electricity bill
Before the assessment begins:
- Ensure any planned home improvements are complete
- Confirm documentation checklist (below)
BER Checklist
Having the right documents at hand can ensure an accurate BER reading.
If you can, provide information on:
Readying your home can also help the process go smoothly. Ensure:
- All areas are unlocked and accessible (e.g. attic, outdoor buildings and/or garage)
- All areas in your home that have been extended or upgraded are clearly marked
- You identify the heating system and heating controls
- Check if the documentation you have provided is sufficient
If you can’t provide some relevant documents, the BER assessor will use ‘default values’ or estimates, which could result in your home receiving a lower BER rating.
How long is a BER certificate valid?
A BER certificate is valid for 10 years provided there’s no change to your home that could affect the energy performance.
For unbuilt homes, a Provisional BER based on plans for your home is only valid for 2 years.
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How much does a BER certificate cost?
There is no set fee for a BER certificate so it’s wise to shop around to get the best price.
A typical home or an apartment of 1,200 sq could cost around €150 while a large house, duplex, or penthouse could cost between €200 and €300*.
Make sure you get written quotes before commissioning a BER assessment and check the following:
- Is the assessor insured and registered
- Is the price quoted inclusive of the SEAI Registration Charge
- Does the price include VAT
*Cost depends on property size, complexity, location, and quotes from assessors.
How BER affects energy efficiency
Ireland’s Building Energy Rating (BER) shows how efficiently a home uses energy for heating, hot water and lighting.
Homes with a higher BER are better insulated and need less energy to stay warm - meaning lower running costs and fewer carbon emissions.
The table below compares the relative efficiency of each BER grade to an A1-rated home.
For example, a C3-rated home uses roughly seven times more energy than an A1 home, so it retains only around one-seventh of the heat under the same conditions.
| BER grade | Relative efficiency (vs A1) | Example home / what it means in practice | |
|---|---|---|---|
| A1 | 100% | Very low running costs; highly efficient, near zero-energy building (NZEB) | |
| A3 | 56% | Excellent efficiency; most new urban homes with solar panels | |
| B1 | 30% | Efficient, modern home with upgrades | |
| B3 | 23% | Retrofitted or modern property; meets SEAI B2 target | |
| C1 | 19% | Average Irish home; moderate comfort and bills | |
| C2 | 17% | Rural home with oil heating; slightly less efficient | |
| C3 | 14% | Typical apartment; rising heating costs likely | |
| D1 | 13% | Noticeably higher bills; good candidate for retrofit | |
| D2 | 11% | Expensive to heat; low comfort; upgrades recommended | |
| E | 9% | Poor energy performance; draughty | |
| F / G | 7% | Very high costs; full retrofit needed |
Relative efficiency (vs A1) is compared to an A1 home, it is not a physical measure of heat kept in a house, but a comparative metric to highlight energy savings across BER grades.
Calculated using CSO’s BER primary energy usage stats. (A1 delivered energy / grade delivered energy) × 100 (A1 = 100%) E.g: C1 → (1,100 / 6,050) × 100 = 18.2%
Despite the calculations used, a BER is only an indication of the energy performance of a home.
The BER calculation
A BER is based on the calculated energy performance and associated carbon dioxide emissions from room and water heating, ventilation and lighting under standardised conditions.
Although a BER takes into account how many people live at the property, it doesn’t include electricity used for purposes other than heating, lighting, pumps and fans.
Used in the calculation are:
- the house dimensions
- the house orientation
- types of window
- level of insulation
- heating & hot water system efficiencies
How to boost your BER
Improving your BER will reduce your energy costs and make your home warmer and more comfortable.
The majority of homes in Ireland are C or D, but the higher your rating the more energy savings you can make.
Here’s some ways to boost your BER and save money on your energy bills and enhance the value of your house.
How efficient is a C-rated home?
Most BER-rated homes in Ireland have a C-rating, and were built between 1980 and 2009.
- Gas is the main heating fuel used in a C-rated household (especially C1-rated homes)
- Home heating oil is more prevalent in C2 and C3-rated homes.
C-rated homes are more efficient than D-F rated homes at trapping heat, and may have some form of insulation.
As up to 30% of all heat is lost through the attic, and 35% escapes through walls and doors, the main things that will improve your homes’s BER rating include:
Before carrying out work, you should contact a registered BER Assessor who will visit your home and carry out an assessment.
Once your home is assessed, you will receive an advisory report which will suggest the improvements needed to bring your home to a B2 level.
Estimated heating costs by BER rating
Most Irish homes fall between a C2 and D2 BER, meaning they could cost around four to five times more to heat and light than a new, A-rated home.
The table below, though it excludes costs for home appliances, shows how annual heating, water and lighting costs can change depending on your BER grade:
| BER grade | Estimated annual cost* (€) | Compared with A1 home | What it means in practice | |
|---|---|---|---|---|
| A1 | €518 | Baseline | Very low running costs; near-zero-energy standard (NZEB). | |
| A2 | €736 | 1.4 × more | Excellent efficiency; modern home with solar panels. | |
| A3 | €955 | 1.8 × more | Strong performance; low running costs. | |
| B1 | €1,173 | 2.3 × more | Efficient newer home; manageable bills. | |
| B2 | €1,392 | 2.7 × more | Comfortable efficiency; below national average. | |
| B3 | €1,610 | 3.1 × more | Reasonable, but could benefit from upgrades. | |
| C1 | €1,828 | 3.5 × more | Falls into bracket of average Irish home; moderate comfort and bills. | |
| C2 | €2,047 | 4.0 × more | Slightly below modern standards; easy savings possible. | |
| C3 | €2,265 | 4.4 × more | Typical Irish home; uses around four times more energy than A1. | |
| D1 | €2,527 | 4.9 × more | Older heating system; noticeable heat loss. | |
| D2 | €2,855 | 5.5 × more | Common in older stock; major upgrade potential. | |
| E1 | €3,204 | 6.2 × more | High energy demand; outdated systems. | |
| E2 | €3,554 | 6.9 × more | Very high costs and pricey to heat. | |
| F | €4,034 | 7.8 × more | Inefficient; retrofit recommended. | |
| G | €4,777 | 9.2 × more | Extremely inefficient; deep retrofit needed. |
Figures are illustrative and for comparative purposes only; actual bills vary by supplier rates, home size, heating system, and usage. See the full methodology for more information.
Methodology
We used SEAI BER data showing typical energy use for each BER grade. The costs included don’t include energy costs for household appliances, meaning they are approx 20-30% lower than full annual bills.
- Figures are based on SEAI BER primary-energy values (kWh per square metre per year): a measure of how much energy each type of home is expected to need for heating, lighting, and hot water.
- These values were applied to a 130 m² home, adjusted to reflect the energy a house actually uses (around 40% of the BER’s “primary energy”).
- We assumed 70% of the energy comes from gas and 30% from electricity, which matches how most Irish homes heat and light their homes.
- Costs are calculated using current, standard rates from Electric Ireland and Bord Gáis, and we added in annual standing charges and taxes/levies too.
- The results are rounded yearly costs, made to show how energy efficiency affects typical heating and lighting bills.
BER primary-energy value (kWh/m²/year) × average home size (130 m²) × delivered-energy factor (40 %) × weighted fuel cost (70 % gas @ €0.09/kWh + 30 % electricity @ €0.35/kWh) + annual standing charges, taxies & levies = estimated yearly cost.
Notes on the data
These figures are illustrative examples, not real household bills.
- They’re designed to show how energy use and costs change across BER grades, based on typical heating, hot-water, and lighting use; the areas measured in Ireland’s Building Energy Rating (BER) system.
- A BER’s kWh/m²/year number shows how much energy a home is expected to use per square metre each year for those regulated uses (heat, water, light).
- It’s a calculated estimate, not an energy reading, based on average conditions like insulation, heating system efficiency, and Irish weather.
- Because BERs don’t include appliances such as cookers, washing machines, or TVs, these costs are usually 20–30% lower than a full annual bill from an energy supplier.
- Energy prices are worked out using a blended average of current standard gas and electricity rates, so they represent a national average rather than any one supplier’s tariff.
Sources:
What grants and financial help are available?
The SEAI offers a range of Home Energy Grants for homeowners and those undertaking a self-build. Home Energy Grants are available for the following:
- Insulation - up to €8,000
- Heating Controls - up to €700
- Heat Pump Systems - up to €6,500
- Solar PV panels - up to €1,800
- Solar Water Heating - up to €1,200
What’s the SEAI one stop shop?
This SEAI’s one stop shop is a full-serviced home energy upgrade. It includes a home energy assessment, grant application, project management and any contractor work.
It’s a good option for homeowners who want multiple home energy upgrades and don’t want the hassle of managing a large project themselves.
Can you borrow money to carry out the work?
Yes, some other one stop shop packages, like An Post’s Green Hub or the credit union’s Greener Homes, include a loan as part of the offering.
As well as managing your grant application, BER assessment and contractor work, they’ll include a loan to cover any remaining costs.
Several Irish banks also offer Green personal loans and homeowner loans designed for improving your home’s energy efficiency. You’ll just need to provide evidence of work and grants obtained to benefit from discounted loan rates.
Compare discounted Green loans
Green mortgages
Some Irish banks are offering discounted mortgage rates for homeowners with a good BER rating. They’re called Green mortgages and are worth considering if your home has a rating of B3 or better.
Bank of Ireland even offers an innovative fixed mortgage based on a building’s BER Rating, with discounts applied on a sliding scale: so the higher your BER, the larger the discount.
Find out more about Green mortgages and whether you could qualify for this type of mortgage from some of Ireland’s leading banks like Bank of Ireland in our helpful guide.
BER FAQs
What do BER ratings like B2, C1, and D2 mean?
A Building Energy Rating (BER) measures how energy efficient your home is, from A1 (most efficient) to G (least efficient).
- B2-rated homes are highly efficient, often featuring modern insulation, condensing boilers or heat pumps, and renewable systems like solar PV.
- C1-rated homes are moderately efficient, typically with good insulation and modern gas or oil heating.
- D2-rated homes tend to have older boilers, minimal insulation, and higher energy bills.
A higher rating means a warmer, cheaper-to-run home that’s more attractive to buyers and may qualify for SEAI grants or green mortgage discounts.
How much does it cost to upgrade from D2 to C1 or better?
Costs depend on your home’s size and condition, but typical improvements, such as attic and wall insulation, boiler replacement, or new heating controls, range from €5,000 to €10,000 after SEAI grants.
Homes aiming for B2 or better may need additional measures like external wall insulation, triple glazing, or renewable systems.
Which upgrades give the best BER improvement for the money?
The most cost-effective upgrades include:
- Attic insulation quick, affordable, and immediately beneficial.
- Wall insulation (cavity or external).
- Upgrading to a condensing boiler or heat pump.
- Adding heating controls to better manage energy use.
- Solar PV also helps by reducing grid electricity demand, improving your overall energy performance.
Can you sell a home with a low BER rating?
Yes. All homes for sale or rent in Ireland must have a BER certificate, but there’s currently no minimum legal rating.
However, a low BER (like D2 or lower) can make a property less appealing to buyers due to higher running costs and lower comfort levels.
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