Are insulation companies regulated in the UK?

There is no single licence, but credible installers hold TrustMark, PAS 2035 (whole-house), NIA/CIGA (cavity) and/or MCS (where heating is involved).

Should I use a local or national insulation company?

Both can be good. Local firms often cost less and know regional housing; nationals may offer broader guarantees. Check accreditations and references either way.

Does PAS 2035 apply to insulation?

Yes, for publicly funded or whole-house retrofit. PAS 2035 requires an assessment and coordinated plan so insulation doesn't cause damp or wasted spend.

Best Insulation Companies in the UK

Insulation is one of the highest-return home improvements you can make, but install quality varies enormously. A poorly specified job wastes money and can cause damp. This guide explains what a competent UK insulation company looks like, the guarantees that actually protect you, and where to find vetted installers.

Last reviewed: August 2026Sources: National Insulation Association · PAS 2035 · Energy Saving Trust

What good looks like

For whole-house or solid-wall work, look for PAS 2035 compliance and a TrustMark-registered installer — this means a proper retrofit assessment rather than a single-measure sale. For cavity wall insulation, membership of the National Insulation Association (NIA) or Cavity Insulation Guarantee Agency (CIGA) registered installers is the standard. If the insulation interacts with your heating system, MCS certification matters too.

The guarantees that matter

Cavity wall insulation should come with a 25-year CIGA guarantee. Internal wall insulation is covered by the Insulation Assurance Authority (IAA) scheme. Check the product warranty from the manufacturer as well, and make sure the guarantee is transferable if you sell the home.

Red flags

Be wary of cold-callers, upfront fees, quotes with no written survey, or pressure to use a specific grant you didn't apply for. A competent installer surveys first, explains the measure, and puts the scope in writing.

Use a vetted directory

Our open installer directory lists UK energy efficiency companies and training providers you can filter by service. Pair it with the scheme tracker to see which grants apply to your home.

What it should cost

Costs vary by measure and property. See our open benchmark dataset for current UK ranges on loft, cavity and solid-wall insulation, and the full insulation cost guide for detail.

FAQs

Are insulation companies regulated in the UK?: There is no single licence, but credible installers hold TrustMark, PAS 2035 (whole-house), NIA/CIGA (cavity) and/or MCS (where heating is involved).
Should I use a local or national insulation company?: Both can be good. Local firms often cost less and know regional housing; nationals may offer broader guarantees. Check accreditations and references either way.
Does PAS 2035 apply to insulation?: Yes, for publicly funded or whole-house retrofit. PAS 2035 requires an assessment and coordinated plan so insulation doesn't cause damp or wasted spend.