Choosing an insulation contractor in Ireland

The essentials

Before you accept a quote

For an individual grant from SEAI (Ireland’s state energy agency), you manage the job yourself and must use a contractor registered for the type of work.
Registration is not an endorsement. SEAI does not approve, guarantee or warranty a company or its work.
Get several written quotes, ask for references, and sign a written contract before work starts.
Do not let work or material purchases start before SEAI has approved your application.

The contractor you pick decides how well the insulation works, and for an SEAI individual grant it also decides whether the grant is paid. This page covers what SEAI requires and what you should ask for yourself. For the grant routes, see SEAI insulation grants explained.

What SEAI requires

A registered contractor. For the individual grants, you must choose a contractor registered with SEAI. The contractor must be registered for the type of work being done, such as attic or wall insulation.
Approval before work. Apply to SEAI (you or your contractor can apply, through SEAI’s online grant application) and get approval before the contractor buys materials or starts. Then accept SEAI’s grant offer (within 30 days) before any work begins. Work started earlier is not covered. The numbered application steps are in the grants guide.
A BER after the work. The home needs a published BER (a building energy rating certificate) from a registered assessor once the work is done. Agree who books it: SEAI suggests the homeowner contacts an assessor, ideally once the start date is known, so payment is not delayed. Search for one on SEAI’s registered assessor search.

If you would rather not manage the job, a participating One Stop Shop can run it from start to finish. A One Stop Shop is a company that manages the whole grant and building job for you; SEAI lists them on its One Stop Shop page. For fully funded work under Warmer Homes, SEAI chooses the contractor: see its Warmer Homes page. Check the one you pick is registered for the grant you are using.

What registration does not tell you

SEAI registration is not an approval or a guarantee of good work, so do your own checks: a registered company can still do poor work.

Questions to ask before you accept a quote

Are you registered with SEAI for this type of work, and what is your registration number?
Which products will you use, and what thickness? Is the product certified for use in Ireland, for example with an NSAI Agrément certificate (NSAI’s assessment of a product for stated uses)? For wall insulation SEAI requires a copy in the safety file.
What exactly is in the price: scaffold, repairs, making good (repairing and redecorating anything the work disturbs), redecoration, ventilation, disposal?
Is VAT included, and at what rate?
How long will the job take, and when can you start once SEAI approves?
Who handles the paperwork, and who is on site?
What warranty or guarantee do you give, and for how long? Is it in writing?
Can I speak to two or three recent customers?

Compare quotes properly

SEAI recommends shopping around. Get at least three written quotes for the same type of insulation and the same extent of work, then compare them line by line. A much lower price can mean a thinner product, fewer walls, or leaving out repairs. The grant is the same whichever contractor you pick, so compare the full price before the grant on every quote.

Sign a contract

Have a written contract before the installation starts. SEAI says it should set out the works, the prices, the timing, the payment terms and the warranties. If the company refuses to give you one, SEAI urges you not to proceed and to notify it.

If the contractor offers to take the grant off your bill, the contract should say how much you pay, when, and what happens if SEAI does not pay the grant.

After the work

Check the work against the quote before you sign off. Keep the invoice, the guarantee and the BER for your records. Do not pay the final balance until the work is finished and you have what SEAI needs to pay the grant. That means the contractor’s safety file (the documents the contractor must give you for inspection; SEAI’s guidance lists them in section 4.2), a BER (energy rating certificate) and the signed Declaration of Works and Request for Payment forms, which SEAI posts with your offer letter. If your grants exceed 10,000 euro in a calendar year, SEAI requires your tax clearance certificate: Revenue’s confirmation that your tax affairs are in order. You apply to Revenue for it. The complete list is under step 6 of How to apply for the individual grants. The invoice is for your records and for the contractor’s claim; it does not replace those forms.

Guides by measure: attic insulation, cavity wall insulation, external wall insulation and internal wall insulation.

Common questions

How do I check a contractor is registered?

Use SEAI's contractor search and look for the company by name, then ask the company for its registration number. Check that it is registered for the type of work you want, for example attic or wall insulation, because registration is by work type.

Can the contractor take the grant off my bill?

Some registered contractors will charge you the price minus the grant, then claim the grant from SEAI themselves; SEAI's payment request form then carries the contractor's bank details so the grant goes to them, not to you. Agree this in writing before work starts.

What if the contractor will not give me a written contract?

SEAI urges you not to proceed with that company and to tell SEAI. A contract protects you if there is a dispute.

Can I change contractor after I apply?

SEAI allows you to change contractor before the installation starts, by cancelling and applying again. Ask SEAI before you change.

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.