New SEAI data covering 1,406 homes upgraded in 2025 shows that the median home energy upgrade cost in Ireland ranges from €20,235 for apartments to €45,067 for detached houses – after government grants are applied. Most homeowners (74%) spent between €30,000 and €75,000 on the full works.
If you have been putting off a home energy upgrade because you are not sure what it will cost, the Sustainable Energy Authority of Ireland (SEAI) has now published its latest cost data.
Based on 1,406 privately owned homes completed through One Stop Shops between January and December 2025, the figures show what Irish homeowners are spending – and how much the State is covering.
Home Energy Upgrade Cost by Property Type
The table below shows median costs – meaning half of all upgrades came in below these figures and half above, giving a middle-ground view rather than a best- or worst-case scenario.
| Home Type | Total Works Costs | SEAI Grant | Your Cost | BER Improvement |
|---|---|---|---|---|
| Apartment | €30,345 | €11,300 | €20,235 | D1 → A3 |
| Mid Terrace | €55,250 | €18,813 | €37,266 | E1 → A2 |
| Semi-D / End Terrace | €60,805 | €21,700 | €38,932 | D2 → A2 |
| Detached | €69,795 | €24,500 | €45,067 | D2 → A2 |
Source: SEAI One Stop Shop Median Costs and Grants, January – December 2025.
How Much Will the SEAI Grant Cover?
SEAI grants under the National Home Energy Upgrade Scheme cover a meaningful portion of total costs, but the exact amount depends on your property type and the measures installed.
Based on the 2025 data, grants ranged from €11,300 for apartments to €24,500 for detached homes.
In percentage terms, this typically offsets 33–37% of total works costs – a significant reduction, but it does mean homeowners still need to plan for a out-of-pocket investment.
It is also worth noting that grants are paid directly to the One Stop Shop contractor, not to you.
You only ever pay your net share of the bill, making the process more straightforward than claiming money back after the fact.
What Does A Home Retrofit Typically Include?
The higher costs for larger homes reflect the scope of work involved. Across all property types, the efficiency and cost effectiveness of running a heat pump is the objective of most packages, replacing gas or oil heating with an electric alternative.
To achieve this, typical measures include:
- Windows and doors: Replacing draughty single-glazed units with high-performance double or triple glazing.
- Wall insulation: External, internal, or cavity wall insulation depending on your home’s construction type.
- Attic insulation: Standard for mid-terraces, semi-ds, and detached homes — one of the most cost-effective measures available.
- Solar panels (PV): Increasingly common, especially in semi-ds and detached homes, to reduce electricity bills and offset heat pump running costs.
- Ventilation: Mechanical ventilation with heat recovery (MVHR) is typically installed alongside a heat pump to maintain air quality in a well-sealed home.
Apartments tend to have a simpler scope, heat pump, windows and doors, and wall insulation, which explains the lower overall cost compared to houses.
How Costs Break Down Across Irish Homes
The 2025 SEAI data gives a useful picture of the spread of total upgrade costs across the 1,406 homes in the dataset:
| Total Works Cost Range | % of Homes |
|---|---|
| Less than €30,000 | 5% |
| €30,000 – €50,000 | 21% |
| €50,000 – €75,000 | 40% |
| More than €75,000 | 34% |
The largest group (40% of homes) spent between €50,000 and €75,000 on the full package. Only 5% of homes came in below €30,000 – showing that a deep retrofit is a significant financial undertaking, even with government support.
However, the BER data tells an encouraging story: the average BER improvement across all home types was from D2 to A2, representing a dramatic improvement in energy performance and a corresponding reduction in heating bills.
Is the Investment Worth It?
For most homeowners, the answer depends on your starting point, your current energy bills, and how long you plan to stay in the property.
A home upgraded from a D or E BER rating to an A2 rating will have significantly lower heating costs – an advantage given the current volatility of gas and oil prices.
Heat pumps, when properly installed in a well-insulated home, can reduce heating costs by 30–60% compared to a gas boiler.
There is also a property value dimension. A higher BER rating is increasingly factored into valuations, and with the pending introduction of minimum energy performance standards for rental properties in Ireland, energy efficiency is becoming a financial necessity as much as a comfort improvement.
How to Start Your Home Retrofit Upgrade
The SEAI’s One Stop Shop model is designed to simplify the process. Rather than managing multiple contractors yourself, a registered One Stop Shop will:
- Carry out a technical assessment of your home
- Design a tailored upgrade package based on your property type and budget
- Manage all contractors and the grant application on your behalf
- Deliver the completed upgrade to SEAI standards
You can find a full list of registered One Stop Shops on the SEAI website at seai.ie.
Retrofit Ireland is an SEAI-registered One Stop Shop. If you would like to understand what a retrofit might cost for your specific property, register here for a free assessment (when you have a valid BER).
Data source: SEAI National Home Energy Upgrade Scheme — One Stop Shop Median Costs and Grants, January to December 2025. Based on 1,406 private homes. Median costs represent the mid-point of all upgrade costs recorded.