Why most Irish homes are under-insulated
Over 70% of Irish homes were built before modern building regulations came in. That means most houses — pre-1980s in particular — have little or no wall insulation, minimal attic insulation, and are leaking heat constantly.
This isn't just a comfort problem. An under-insulated home costs significantly more to heat. Every kilowatt of heat that escapes through the ceiling or walls is money straight out the door.
Insulation is not an upgrade — it's bringing the house up to where it should be. It's also the lowest-cost energy improvement most homes can make, with payback periods of 2–7 years depending on the type.
Up to €8,000
SEAI insulation grants
External wall insulation for a detached home. Lower amounts for other types and sizes.
2–7 years
Typical payback
Attic insulation often pays back in under 3 years. Solid wall takes longer.
Biggest lever
BER impact
Insulation is the single biggest factor in improving a BER rating.
Types of insulation — which suits your home
Irish homes fall into two broad categories: those with cavity walls (most homes built from the 1940s to the early 2000s) and solid-wall homes (older stone or brick construction, common in rural areas and city terraces).
The right type of insulation depends on your wall construction, your budget, and how much disruption you're willing to accept.
Attic / roof insulation
The easiest and cheapest upgrade. Heat rises — a poorly insulated attic lets it straight out. If you have an accessible attic, this is always the first thing to do. Typically mineral wool or blown fibre laid between and over the joists. Installation takes a day. Payback can be 2–3 years.
Cavity wall insulation
Most semi-detached and detached homes built between 1940 and 2000 have a gap (cavity) between the inner and outer leaf of the wall. If that cavity is empty, insulation can be injected through small holes drilled in the outer wall — typically complete in half a day. Very cost-effective. Check first that your cavity is suitable: no moisture issues, minimum 50mm gap.
Internal wall insulation (dry lining)
For solid-wall homes where cavity fill isn't an option. Insulated boards are fixed to the interior surface of external walls. Effective but disruptive — it reduces room size slightly and requires skirting, architraves, and sockets to be moved. More of a renovation project than a simple upgrade.
External wall insulation (EWI)
Insulation boards are fixed to the outside of the house and rendered over. The most expensive option but also the most effective — it wraps the entire building envelope and improves the appearance of the house. Requires planning permission in some cases. The right choice when the house needs rendering anyway or when internal disruption needs to be avoided.
What it costs — realistic figures before grants
Installed costs vary by house size, property type, and contractor. These are typical ranges for a standard semi-detached home:
- Attic insulation: €1,000–€2,000 installed
- Cavity wall insulation: €1,500–€2,500 installed
- Internal wall insulation: €10,000–€20,000 depending on floor area
- External wall insulation: €15,000–€25,000 depending on floor area
Get three quotes from SEAI-registered contractors before committing to anything. Prices vary considerably between contractors and regions.
SEAI insulation grants 2026
Attic insulation
Up to €2,000- What it covers
Grant amount depends on property type: €2,000 for a detached home, €1,300 for semi-detached or end-terrace, €1,200 for a mid-terrace, €800 for an apartment. Higher grants (up to €2,500) are available for homeowners on qualifying welfare payments or first-time buyers.
- Who qualifies
- Must use an SEAI-registered contractor. Figures updated February 2026.
Cavity wall insulation
Up to €1,800- What it covers
€1,800 for a detached home, €1,200 for semi-detached or end-terrace, €800 for a mid-terrace, €700 for an apartment. Higher rates (up to €2,300) for homeowners on qualifying welfare payments from March 2026.
- Who qualifies
- Cavity must be assessed as suitable before work starts. SEAI-registered contractor required.
Internal wall insulation
Up to €4,500- What it covers
€4,500 for a detached home, €3,500 for semi-detached or end-terrace, €2,000 for a mid-terrace, €1,500 for an apartment. Available for solid-wall homes where cavity fill is not possible.
- Who qualifies
- For homes where cavity wall insulation is not suitable. SEAI-registered contractor required.
External wall insulation
Up to €8,000- What it covers
€8,000 for a detached home, €6,000 for semi-detached or end-terrace, €3,000 for a mid-terrace or apartment. The largest insulation grant available. Also applies when adding an outer insulation layer to a cavity-wall home.
- Who qualifies
- SEAI-registered contractor required. Confirm planning permission requirements before starting.
Warmer Homes Scheme — free insulation for qualifying households
If you're on a qualifying social welfare payment — Fuel Allowance, Jobseeker's, One-Parent Family Payment, or similar — you may be eligible for the Warmer Homes Scheme. This is a fully-funded programme that covers attic insulation, cavity wall insulation, and other energy upgrades at no cost to you.
It's separate from the standard SEAI grants. Apply directly through SEAI. Waiting times vary by area — apply early.
How insulation improves your BER rating
Insulation is the single biggest lever for improving a BER rating. A typical 1970s semi-detached with no attic insulation and empty cavity walls might sit at D or E. Filling the cavity and topping up the attic can move it to C — sometimes in a single day.
This matters practically, not just on paper. Selling or renting: a poor BER puts buyers and tenants off, and improving it before you sell adds value. Green mortgages: some lenders offer better rates for homes with a B2 or better BER. And some SEAI grants require a minimum BER or a post-upgrade assessment.
See parce.ie/ber for a full explanation of how the rating system works and what steps have the biggest impact on your score.
The One Stop Shop — SEAI coordinates the whole project
If your home needs multiple upgrades — attic insulation plus cavity wall plus heat pump, for example — the One Stop Shop is worth knowing about.
SEAI coordinates the full upgrade: energy assessment, contractor management, and grant applications all handled by one registered provider. You deal with one point of contact instead of managing three separate contractors.
It's not always the cheapest route — you're paying for the coordination — but for complex retrofits, the reduction in hassle is real. See parce.ie/grants for more on how it works.
How to get it done
You must use an SEAI-registered contractor to claim any of the grants above. Using an unregistered contractor means losing the grant — and you cannot claim it after the fact.
Steps: check the SEAI register for registered insulation contractors in your area, get at least three quotes, make sure your contractor submits the grant application before work starts (not after), then pay the net amount on completion — SEAI pays the grant directly to the contractor.
Questions to ask every contractor:
- Are you SEAI-registered for this specific type of insulation?
- Will you handle the grant application on my behalf?
- Is my cavity suitable for fill, and how do you assess this?
- What guarantee do you offer on the workmanship?
- What U-value will I achieve after installation?
We're building a verified insulation contractor network. Email hello@parce.ie if you can recommend a reliable installer in your area.
Common questions about insulation in Ireland
What Irish homeowners most want to know before starting.
Do I need planning permission for external wall insulation in Ireland?▾
Usually not — but it depends. External wall insulation is generally exempt development, meaning no planning application is needed for most homes. However, exceptions apply if your home is a protected structure, in an Architectural Conservation Area (ACA), or in certain designated zones. Always confirm with your local planning authority before starting, especially in older town centres. Your SEAI-registered contractor should be able to advise.
Can I claim multiple insulation grants at the same time?▾
Yes. SEAI allows you to claim grants for more than one insulation type in the same application — attic and cavity wall together, for example. From March 2026, homeowners who previously received a grant for cavity or internal wall insulation can also apply for a second wall measure. If you're doing a full retrofit, the One Stop Shop may be the most efficient way to combine multiple grants in one managed project.
How long does attic insulation take to install?▾
For a typical semi-detached home, attic insulation takes a few hours — usually half a day to a full day depending on the attic size and whether existing insulation needs removing first. It's one of the least disruptive energy upgrades you can make. Most installers will also check that the attic has adequate ventilation and that the water tank (if in the attic) is properly lagged.
What's the payback period for insulation in Ireland?▾
It varies by type. Attic insulation typically pays back in 2–4 years — sometimes faster in a poorly insulated older home. Cavity wall insulation pays back in around 3–7 years. Solid wall insulation (internal or external) has a longer payback — often 10–20 years for the insulation cost alone — though the combination of improved BER, comfort, and reduced maintenance changes the overall picture. All calculations assume average Irish energy prices; actual savings depend on your home and heating system.
Can renters get insulation grants in Ireland?▾
The standard SEAI Better Energy Homes grants are for homeowners only. Renters cannot apply directly. However, landlords can apply for insulation grants on rental properties they own — so if you're renting a cold, poorly insulated home, you can point your landlord towards the SEAI scheme. The Warmer Homes Scheme (for qualifying welfare recipients) covers renters in certain circumstances — check SEAI directly for current eligibility conditions.
What's the difference between the One Stop Shop and getting grants separately?▾
With the individual grant route, you find and manage your own SEAI-registered contractors for each type of work, and each contractor handles their part of the grant application. With the One Stop Shop, a single registered provider coordinates everything — assessment, contractors, and all grant paperwork in one place. The One Stop Shop suits larger, multi-measure retrofits. For a single measure like attic insulation, the standard grant route is simpler and often cheaper.
Explore related pages
- →SEAI home energy grantsEvery SEAI grant in one place — including the One Stop Shop and Warmer Homes Scheme.
- →BER certificatesHow the BER rating system works and what insulation does to your score.
- →Heat pumps IrelandInsulation is often the first step before installing a heat pump.
- →Solar panels IrelandReduce what your home needs first — then size your solar system accordingly.