What insulation costs in Ireland

The essentials

A useful starting figure, then a surveyed quote

The tables below show SEAI’s January–June 2026 median costs before grants, not current quotes or guaranteed price ranges.
The right wall method depends on construction and condition. Cavity, internal and external wall insulation are not interchangeable items to choose by price alone.
Budget for repairs, access, ventilation, finishing and assessment as well as insulation. Ask which are included, with VAT stated.
Keep your full project price, confirmed grant and payment dates separate. A grant paid after completion does not fund an earlier contractor bill.

Published insulation costs by house type

SEAI, Ireland’s state energy agency, reports these medians for January to June 2026. They are costs before grants. A median is the middle recorded cost, with half the jobs cheaper and half dearer; it is neither a minimum price nor a quote.

The source does not state whether VAT is included. Check VAT and the complete work included in each contractor’s quote before comparing it with these figures. The recorded jobs differ in size and scope.

Attic insulation

Insulation above the top-floor ceiling; roof-slope work can have a different scope.

Attic: median completed-job cost, January to June 2026
House type	Cost before grant
Detached	€2,700
Semi-detached or end of terrace	€2,101
Mid-terrace	€2,200
Apartment	€1,515

Read the attic insulation guide for suitability, work scope and grants.

Cavity wall insulation

Filling a suitable gap between two wall layers, after a survey.

Cavity wall: median completed-job cost, January to June 2026
House type	Cost before grant
Detached	€2,350
Semi-detached or end of terrace	€1,585
Mid-terrace	€1,250
Apartment	€1,036

Read the cavity wall insulation guide for suitability, work scope and grants.

Internal wall (dry-lining) insulation

Insulating the room side of outside walls; allow for making the rooms usable again.

Internal wall (dry-lining): median completed-job cost, January to June 2026
House type	Cost before grant
Detached	€8,600
Semi-detached or end of terrace	€9,843
Mid-terrace	€9,804
Apartment	€5,736

Read the internal wall (dry-lining) insulation guide for suitability, work scope and grants.

External wall insulation

Insulating outside walls beneath a new finish; access and edge details affect the quote.

External wall: median completed-job cost, January to June 2026
House type	Cost before grant
Detached	€26,500
Semi-detached or end of terrace	€23,219
Mid-terrace	€14,000
Apartment	€11,300

The apartment figure comes from only five completed homes. Ask for a building-specific survey and quote rather than treating that small sample as a dependable apartment budget.

Read the external wall insulation guide for suitability, work scope and grants.

Source: SEAI’s individual-upgrade cost sheet. These insulation figures draw on different groups of completed jobs; adding them does not give a whole-house budget.

Use the figures to prepare, then price your house

Find your house type in the tables, then open the relevant guide before asking for quotes. A semi-detached house and an end-of-terrace house share a category: both have an exposed side wall. A mid-terrace has neighbours on both sides. An apartment figure describes work on completed homes in the source sample; it does not price an entire block or establish permission to change shared walls or roofs.

Do not convert a house-type median into a price per square metre by dividing it by your floor area. Floor area, attic area and outside wall area are different measurements, and the source does not give the treated areas behind each median. Where a contractor quotes per square metre, ask which area it measures and request the finished-job total.

SEAI’s figures record costs submitted when grants were paid. They do not specify a complete list of included repairs and finishing for every job. A quote above or below the median needs a scope comparison, not an automatic judgement that it is expensive or incomplete. Ask the contractor to explain the difference in writing.

Choose the suitable work before the cheapest price

Start with a survey identifying existing insulation, moisture problems and the construction of each part of the house. A retrofit assessor or building professional can help plan several connected upgrades; the installer must also survey the work they are quoting.

Attic: access, existing insulation, storage platforms, the hatch, pipe protection and maintaining roof ventilation affect the job. Insulating roof slopes for a room in the roof is a different scope from laying insulation above a ceiling.
Cavity wall: the gap between two wall layers must be suitable for filling. The survey should address wall condition, exposure to driving rain and any existing fill. A cheap cavity quote does not make a solid wall suitable for cavity insulation.
Internal wall: allow for the treatment of corners and window openings, moving sockets or radiators, and restoring plaster, skirting and decoration. Ask how moisture and room ventilation will be managed.
External wall: ask about scaffold, surface repairs, the finish, window sills, roof edges and moving pipes or cables. Changes around the electricity connection may need ESB Networks involvement; the contractor should identify that before pricing the final scope.

Our older and solid-wall homes guide explains why traditional stone, brick and earth construction needs a different moisture assessment. Ordinary wall grants exclude traditional homes. Check SEAI’s Traditional Homes Pilot, the alternative support scheme for these homes, before budgeting for a wall grant. The wall-grant figures in Check grant eligibility do not cover that pilot.

The three wall methods are usually alternatives for a particular wall, though a mixed-construction house may need a designed combination. SEAI’s individual wall grant requires a whole-surface solution covering all outside walls; a quote for only one cold room is not the same grant-funded scope. Ask the contractor how the complete proposed treatment meets that rule.

Build a budget for the finished work

Send the same written survey findings and requested scope to each contractor. Ask for an itemised total that makes these groups visible:

Insulation work: measured area, product, thickness, preparation, labour and access equipment.
Enabling repairs: leaks, damp or damaged surfaces that need fixing before insulation can be installed.
Connected work: ventilation, pipe and electrical changes, work around windows or roof edges, and any required design or permissions.
Making good: waste removal and reinstating finishes, flooring, fitted items and decoration affected by the work.
Assessment and records: surveys, any design fees, the final Building Energy Rating (BER) assessment where required, completion documents and warranties.

Have VAT stated separately or explicitly included in the final payable total. Confirm which items the main contractor includes, which you must arrange separately, and how a provisional allowance will become a fixed price. A provisional allowance is money set aside for work whose final cost is not yet known.

Keep a separate reserve for genuinely unknown work, based on the surveyor’s advice about your home. Agree who can authorise extras and require their price before they proceed. Do not add a standard percentage and assume it covers known repairs missing from the quote.

For floor insulation, get a separate surveyed price. Raising a floor above an existing slab and demolishing and replacing it have very different consequences for levels, doors and services. Neither the wall tables nor a whole-home median can price that decision.

Put grants and payment dates beside the quote

Use Check grant eligibility to screen possible support for your home, then confirm the route and eligible work with SEAI or your registered provider. The grant guide explains standard and higher amounts, previous-support conditions and the application steps. The amount a household can receive is not always the standard amount printed beside a historical median.

Write down three separate things: the full agreed project price, the confirmed grant towards eligible work, and the remaining cost you must fund. Include separate repairs and fees once, even if they are on another supplier’s invoice. For individual grants, the support cannot exceed eligible expenditure; it does not turn unrelated renovation into funded insulation.

Then put the deposit, progress payments, final bill and expected grant payment on a calendar. With a self-managed individual grant, you normally pay the contractor and claim after completed work, the final BER and paperwork. A registered contractor may agree to deduct the grant from your price; have that arrangement written into the contract. Keep money available for payments that fall before reimbursement.

A registered One Stop Shop manages upgrades and can also manage individual measures. Its qualifying whole-home scheme deducts approved grants upfront from its invoice. Ask which scheme the quote uses, what you pay at each stage and who bears the cost if grant conditions are not met. Our route comparison explains the distinction. If you may qualify for fully funded work, check Warmer Homes before paying privately for the same work.

A whole-home upgrade needs its own proposal

SEAI’s One Stop Shop cost sheet covers complete projects, often combining insulation with heating, windows, ventilation and solar panels. It describes a different set of homes from the individual tables. It cannot tell you the insulation-only share of those projects.

Do not add the individual medians to estimate a package or subtract a median grant from a median works cost to invent your final payment. Different medians can represent different jobs. Request a surveyed proposal showing each upgrade, shared access costs counted once, design and assessment fees, exclusions, approved grants and the total you pay.

Use the which insulation first guide to plan the sequence. Preparing wall or floor details for later work can avoid paying to disturb a finished room twice. A cheaper first phase can still be poor value if it must be undone.

Your next step

Choose the relevant guide and arrange a survey. Use the SEAI contractor search to find installers registered for the proposed individual work, get comparable written quotes and choose your contractor. Apply and accept the grant offer before work starts or materials are bought. If using a One Stop Shop, have it confirm the scheme, approval and payment schedule before starting. Keep the agreed scope and any later priced changes with your invoices.

Common questions

Why does a mid-terrace sometimes cost more than a semi-detached house?

Each SEAI median comes from a different group of completed jobs, with different sizes, access and work scopes. The figures are observations, not a price list that must rise with house size. Compare quotes for the same measured work on your own house.

Can I subtract the grant from the median to find my cost?

That would subtract a possible grant from someone else’s historical job figure. Use your own written quote and confirmed eligible grant instead, including any separate repairs, fees or finishing. SEAI’s individual grants cannot exceed eligible expenditure, and some households qualify for a higher amount. Check payment dates as well as the final cost.

Why is there no floor-insulation price in the tables?

SEAI’s individual-upgrade cost sheet does not publish a floor-insulation median. A whole-home project total cannot isolate it. Ask for a floor survey and an itemised quote covering lifting or demolition, insulation, protection against damp and radon (a radioactive gas from the ground), changes to pipes and wiring, and the finished floor. See the floor insulation guide.

How quickly will insulation pay for itself?

These job-cost figures do not establish your annual bill saving. Ask a home energy assessor to compare the proposed work with your home’s condition, heating, bills and likely use. Have them show the estimated reduction in energy use and the estimated euro saving separately, stating the energy prices and heating habits assumed. Neither is a guaranteed saving. Choose the work with comfort, condition and the wider upgrade plan in mind too.

Work out your own numbers

Grant total: add up what each SEAI route pays for your upgrades.
Which grant route: five questions to find where to apply first.

Sources and review

Reviewed by Rudy Greene on 31 October 2026. Sources were last checked on 30 October 2026. The review checks published guidance; ask a contractor to survey and design the work for your home.