Do I have to use one of these companies to get the grant?

Yes. SEAI only pays a grant on work done by a company on its register, and the company claims it on your behalf. Work done by anyone else is not covered, however good it is.

How many quotes should I get in Donegal?

Three, from companies registered for the same job, and ask each for a written breakdown. Quotes for the same house often differ by thousands because they include different work, not because one is dearer.

Is this list in any order of merit?

No. Companies based in Donegal come first, then the ones that travel to it, then One Stop Shops, then alphabetical. Being on the register means the paperwork is in order, not that the work is good.

Cavity wall insulation installers in Donegal

49 companies on the SEAI register are based in or serve Donegal for cavity wall insulation (register as of 8 September 2026).

Insulation boards fixed to the outside walls of a terrace mid-job, meter boxes hanging clear of the wall. — Garrick Close, Kingston upon Hull: bungalow renovations, November 2023 · Hullian111 · CC BY-SA 4.0 · Photo credits

Based in Donegal

7 of them. Sorted by what they are registered for, then by name — this is not an order of merit.

AC Insulation
Attic insulationCavity wall insulationInternal wall insulation
Based in Donegal · serves Connacht and Ulster · SEAI no. 17750
Based in Donegal.
BCBAL Ltd T/A McGee Insulation
Attic insulationCavity wall insulationExternal wall insulationInternal wall insulation
Based in Donegal · serves Ulster · SEAI no. 11361
Based in Donegal.
Bio Insulate Ltd
Attic insulationCavity wall insulation
Based in Donegal · serves Connacht and Ulster · SEAI no. 16963
Based in Donegal.
Ecotech Contracts IRI Ltd
Attic insulationCavity wall insulationHeat pump
Nationwide · SEAI no. 19955
Based in Donegal.
Gallen Insulation Ltd
Attic insulationCavity wall insulation
Based in Donegal · serves Dublin, Leinster, Connacht and Ulster · SEAI no. 10936
Based in Donegal.
Premier Solutions NW Ltd
Attic insulationCavity wall insulationInternal wall insulationWindow and door
Based in Donegal · serves Ulster · SEAI no. 16379
Based in Donegal.
Tirconaill Contracts Ltd T/A Mc Taggart Insulation
Attic insulationCavity wall insulationExternal wall insulationHeat pumpInternal wall insulationWindow and door
Nationwide · SEAI no. 15552
Based in Donegal.

Also cover Donegal from elsewhere (42)

These told SEAI they cover the province Donegal is in, or listed it among the counties they serve. Ask how far they travel before you go any further. Names only here; each one's full register row is on its own county page. OSS = One Stop Shop.

Ashgrove Engineering Ltd T/A Ashgrove Renewables (OSS) · Bayview Contracts Ltd (OSS) · Bord Gais Energy Ltd (OSS) · Breffni Insulation Ltd (OSS) · Churchfield Home Services (OSS) · Cooper Insulation Ltd. (OSS) · Electric Ireland Superhomes (OSS) · Envirobead Ltd. (OSS) · Greenwatt Ltd (OSS) · House 2 Home Retrofit Ltd (OSS) · Kingdom Installation Ltd (OSS) · Kingspan Insulation Ltd (OSS) · Kore Retrofit Ltd (OSS) · Moston Construction Ltd (OSS) · OHK Energy LTD (OSS) · Retrofit Design Ltd (OSS) · Retrofit Energy Ireland (OSS) · SSE Airtricity Energy Services Ltd (OSS) · AB Teague Enterprises Ltd · All In Insulation · Anthony Coughlan Heating & Plumbing TA C&S Construction Services · C.D.M. Contracts Ltd · Clar ICH Ltd · Derchil Limited t/a CosiHomes · Eamonn Finn · Eco Home Insulation · Ecotec Insulation Ltd · Ecowise Insulation Ltd · Evertherm Ltd T/A Annalee Energy Ltd · Innovate Insulation Ltd · Jacob Insulation Limited · Kelly Insulation Heating & Plumbing · Kingscourt Insulation Ltd · Leitrim Warmer Homes CLG · Meegan Insulations · Metro Insulation Ltd · Midland Warmer Homes Company Limited · National Retrofit & Construction Services Ltd · Premier Insulations · Superior Insulations Ltd · Sustainable Warmth Ltd · Thermowise Insulations Limited

What it costs, and what the grant pays

The grant for a semi-detached house is €1,300. SEAI recorded a middle price of €1,550 for this work last year, which leaves about €250 for you to pay. These are national figures, not Donegal ones — SEAI does not publish prices by county.

What it costs on a home like yours, and what you are left paying

Before you sign

Wait for your grant approval email before any work starts. SEAI does not pay for work that began before it was approved.
Get at least three quotes, and check each one covers the same job — the cheapest quote is often the one that leaves something out.
Check the company is on the register on the day you sign. Companies join and leave it, and this page is a copy taken on one day.
Get it in writing: what is being done, what it costs, when it starts and when it is finished.

How the application works

Ask up to five of them

Fill in one form, tick who you want to hear from, and we pass your details to those companies and nobody else. It costs nothing and you are under no obligation.

Get cavity wall insulation quotes in Donegal

Common questions

Do I have to use one of these companies to get the grant?: Yes. SEAI only pays a grant on work done by a company on its register, and the company claims it on your behalf. Work done by anyone else is not covered, however good it is.
How many quotes should I get in Donegal?: Three, from companies registered for the same job, and ask each for a written breakdown. Quotes for the same house often differ by thousands because they include different work, not because one is dearer.
Is this list in any order of merit?: No. Companies based in Donegal come first, then the ones that travel to it, then One Stop Shops, then alphabetical. Being on the register means the paperwork is in order, not that the work is good.

Other work in Donegal

Listed on SEAI’s public registers on 8 September 2026. Being registered is not an endorsement by SEAI or by us. Check the current register on seai.ie before you sign anything. Not affiliated with SEAI.