Internal wall insulation cost and grants in Ireland

Last reviewed: October 2026

Indicative costs

DanannIQ uses seai completed energy-upgrade cost data for this guide, covering January to December 2025. Where a stored median is available, the displayed range applies the existing DanannIQ planning spread. These figures are planning information, not quotations or guarantees.

Published 2025 completed-project medians. Internal dry lining can also require significant reinstatement of skirtings, sockets, radiators and finishes.

What internal wall insulation does

Internal insulation adds an insulating system to the inner face of external walls. It may be considered where an external approach is unsuitable or the project includes substantial internal refurbishment. Suitability depends on wall construction, condition and a designed moisture strategy.

It differs from filling a suitable cavity and from insulating the exterior. A hollow cavity-block wall is not a conventional fillable cavity. Establish the construction first and compare the practical consequences of each suitable option.

Space, junctions and moisture

The new wall build-up takes room space. Reveals, floor and ceiling junctions, internal partitions and services can interrupt insulation and create thermal bridges. Ask how the design will address these areas rather than judging the project only by the thickness of the main wall layer.

Leaks and damp need investigation before walls are covered. Material compatibility, vapour control and drying behaviour are especially important in traditional or solid-wall homes. Read the older-home guide and seek construction-specific advice; a standard dry-lining approach is not suitable for every wall.

Coordinate airtightness and ventilation with the insulation design. Blocking necessary air supplies is not a moisture solution. SEAI’s SEAI homeowner’s guide to wall insulation explains internal insulation, room-space loss and associated reinstatement.

Disruption and cost scope

Allow for relocating or refitting sockets, radiators, skirtings, fitted furniture and finishes. Kitchens and cabinets can complicate access. Discuss room-by-room work, temporary use of the home and who carries out the electrical and plumbing interfaces.

The cards above reproduce the existing 2025 benchmark records and DanannIQ’s 12% low / 15% high planning spread. The range is modelled, not a published SEAI percentile. Wall area, access, details and reinstatement affect the quote. The cost guide documents the newer live SEAI sample; this task does not replace the calculator’s stored dataset.

Current grant treatment

Standard Individual Grants are €4,500 detached, €3,500 semi-detached/end-of-terrace, €2,000 mid-terrace and €1,500 apartment. The same listed measure can form part of an eligible OSS package; do not combine the two routes’ awards for the same work.

Qualifying homes must meet the construction/occupancy cutoff before 2011 and the whole-surface wall requirements. Previous wall grants have specific second-measure rules: check the exact history with SEAI instead of assuming that any previous insulation either guarantees or excludes support. Obtain approval before works and use the appropriately registered contractor.

Compare complete designs and quotes

Compare internal, external and cavity options for the actual construction, not just their grant amounts. Confirm moisture strategy, junctions, ventilation, finishes, room-space effects and compliance. See SEAI wall insulation and the grants overview for current rules.

Sources and methodology

Cost figures use the existing DanannIQ source record for Internal wall insulation, checked on 2026-09-09. Grant information uses the existing SEAI - Wall insulation record, checked on 2026-09-09. Confirm current rules and application requirements with the official SEAI source.

For more detail on DanannIQ cost ranges and potential grants, read the Methodology & data sources page or browse all upgrade guides.

Planning several measures? Use the SEAI grants overview and whole-project cost guide to put this upgrade in context.

Have a BER Advisory Report? Start your BER-guided plan.