Use our deep retrofit cost calculator for a first approximation. The actual cost will vary from this, mainly depending on:
- Your choice of contractor
- Choice of materials/brands
- Upgrade details (e.g. how many kW of solar panels)
However, it would be fair to say that most deep retrofits cost somewhere between €30,000 and €90,000, excluding grants. The SEAI deep retrofit grant brings the final cost to the homeowner down to somewhere between €17,000 and €65,000.
What is Involved in a Deep Retrofit?
A deep retrofit is a collection of home energy upgrades that bring a home up to a high standard of warmth and energy efficiency. Specifically, this means achieving a Building Energy Rating (BER) of B2 or better. The exact works carried out depend on what your home needs most.
Almost all deep retrofits include insulation upgrades. Installing a heat pump is also very common. Solar panels cap the job off. Here are some basic guidelines:
- Start with insulation
- Attic insulation is the most cost-effective upgrade, so start there
- Walls need at least one kind of insulation, if they don’t already have it
- If you’ll be replacing floors anyway, it will make sense to install underfloor insulation. Otherwise, the expense and disruption may not be worthwhile (except with suspended timber floors).
- Replace any single-glazed windows with double or triple-glazing
- Get as many solar panels as space and budget allow
- Make sure to get high-quality installers for heat pumps in particular. Because professional design and fitting make a huge difference to heat pump performance
Is There A Grant For Deep Retrofits in Ireland?
The SEAI (Sustainable Energy Authority of Ireland) provide grants for deep retrofits via the One-Stop Shop Scheme.
Most Irish homeowners are eligible for a deep retrofit grant. Better yet, you can claim a deep retrofit grant for multiple properties. This includes holiday homes and rental properties. Here are the main requirements:
- Your house was built before 2011 (defined by date of electricity connection)
- Your house has a current BER of B3 or lower
To be awarded the grant, your retrofit contractor will ensure the home:
- Achieves a BER of B2 or better after the retrofit is complete
- Reduces energy usage by at least 100 kWh per square metre of floor are per year
- Does this using energy upgrades that you have not previously got a grant for
The grant amount depends on the exact package of upgrades that you choose. But as a general guide, it will typically be in the range of €15,000-€30,000.
How Long Does a Deep Retrofit Take?
A deep retrofit typically takes several weeks, but there are exceptions, with some jobs completed in a matter of days. It all depends on the specific upgrades – see the table below:
| Upgrade | Duration of Work | Disturbance to Occupants |
| Solar panels Wall cavity insulation | 1-2 days | Minimal – most or all of the work is done from outside |
| Attic insulation Heat pump | 1-3 days | Some disturbance, but no need to move out |
| Underfloor insulation Internal wall insulation | 1-3 weeks | High – you will need to move out |
| External wall insulation | 1-2 weeks | Minimal – all the work is done from outside |
