Comparing insulation installers: accreditations and questions to ask

Different bodies guarantee different things. This table sets out what each accreditation means for an insulation job and when it applies.

Accreditations such as MCS, Gas Safe, NICEIC and NAPIT cover heat pumps, gas and electrical work, not insulation, so they are not the ones to weigh up for an insulation quote.

A guarantee is only as good as the body that backs it. The strongest is the CIGA 25-year guarantee for cavity wall insulation, which is independent of the installer: if the firm ceases trading, the guarantee still stands and covers remedial work. For other measures, look for an insurance-backed guarantee (often via RECC or HIES), which protects you if the installer goes out of business. Be cautious of a guarantee offered only by the installer with no third-party backing, because it is worthless if the company disappears. Always get the guarantee in writing, check what it actually covers (materials, workmanship, consequential damp damage) and confirm its length. A longer guarantee from an unbacked firm is weaker than a shorter, insurance-backed one. Our how-to-choose guide explains how to verify each.

The biggest mistake homeowners make is comparing quotes on price alone. Two quotes can look very different simply because one includes more, or holds better accreditation. Use this checklist to compare like for like:

• Scope: is it the same measure, the same area of the home and the same materials?
• Accreditation: TrustMark, PAS 2030/2035 and (for cavity) CIGA, with verifiable numbers.
• Guarantee: length, what it covers and whether it is insurance-backed.
• Making good: does the price include removing old material, sealing, and redecoration where relevant?
• Timescale: how long the job takes and when payment is due.
• Grant handling: if you are applying for funding, who manages the paperwork.

Comparing this way is exactly what we help with. We connect you with vetted, accredited installers so the quotes you receive are already on a level footing. Get free quotes to compare.

These three are often listed together but they cover different things. TrustMark is the government-endorsed quality scheme: it vets the firm as a business, covering technical competence, trading standards and conduct, and it applies to all home insulation work. PAS 2035 and PAS 2030 are the retrofit standards that apply to grant-funded work. PAS 2035 governs the front end, how a home is assessed and the work designed so it suits the property and avoids damp or ventilation problems. PAS 2030 governs the back end, how the measure is actually installed. In plain terms: TrustMark vets the company, PAS 2035 plans the job, and PAS 2030 fits the job. Grant-funded insulation usually requires all three, so seeing only one named on a quote for grant work is a reason to ask questions.

• TrustMark: vets the firm; applies to all insulation work.
• PAS 2035: assessment and design; applies to grant-funded retrofit.
• PAS 2030: installation; applies to grant-funded retrofit.

Every accreditation worth having can be checked on an official register, and a genuine installer will give you the membership number without hesitation. Verifying yourself takes a few minutes and catches firms that name a body they do not actually belong to. At Insulation Quotes Walsall we always tell homeowners to confirm registration independently rather than take a logo on a van or website at face value.

1. 1TrustMark: search the firm at trustmark.org.uk to confirm registration.
2. 2CIGA: ask for the guarantee reference and check it covers your cavity work.
3. 3NIA, RECC and HIES: confirm membership on each body's own register.
4. 4Trading history: look the company up on Companies House to see how long it has traded and whether it has changed names.

Our how-to-choose guide and guide to spotting rogue installers explain what each check tells you.

A worked example shows why the cheaper quote is not always cheaper. Imagine two quotes for cavity wall insulation on a Walsall semi. Installer A quotes £900 and Installer B quotes £1,150. On price alone, A wins. But comparing like for like changes the picture: A is not CIGA registered and offers only its own guarantee, while B is TrustMark registered, CIGA backed and includes making good. B's extra £250 buys a 25-year independent guarantee that survives the firm going out of business, which on a measure that can cause damp if done badly is the more sensible buy. The table below lays the two side by side.

The cheapest quote is rarely the best because price usually reflects what has been left out. A low figure can mean no accreditation, no insurance-backed guarantee, cheaper material at a thinner depth, or making good and old-material removal quietly excluded so they reappear as extras later. Insulation is also a measure where poor work causes expensive damage: cavity fill done without checking the wall can let damp through, and solid wall insulation designed without PAS 2035 can trap moisture. A slightly dearer quote from a TrustMark-registered, properly guaranteed installer protects you against both the workmanship and the firm disappearing. Judge value on accreditation, scope and guarantee together, then treat price as the tie-breaker between firms that match on everything else. That is the approach we help Walsall homeowners take by shortlisting vetted, accredited installers before you compare. Get free quotes to start.

Comparing installers for grant-funded work has an extra layer, because the funding scheme sets its own rules. Any insulation paid for through ECO4 or the Warm Homes Local Grant must be installed to PAS 2030 and designed under PAS 2035, and the firm must be TrustMark registered, so an installer missing any of these cannot lawfully deliver grant work. When you compare grant-funded quotes, the accreditation check is not optional polish, it is the thing that decides whether the funding stands at all. Beyond that, look at who manages the paperwork and the funding application, because a good installer handles the scheme administration rather than leaving it to you.

In the West Midlands, including Walsall and Dudley, the Warm Homes Local Grant is delivered by Acton Energy, and Walsall Council's LA Flex Statement of Intent can widen ECO4 eligibility. When comparing firms for funded work, ask each how they handle the scheme, confirm their PAS and TrustMark status on the official registers, and check the guarantee that comes with the finished job. Our ECO4 eligibility guide and Warm Homes Local Grant guide explain the schemes, and the cost guide shows how funding changes the maths.

The most common mistakes when comparing insulation installers all share a root cause: judging on the wrong signal. Homeowners pick on price alone, trust a logo on a van without checking the register behind it, or accept a long guarantee without asking who actually backs it. Others compare quotes that are not like for like, because one covers a smaller area, a thinner material or excludes making good, so the figures were never comparable in the first place. A further trap is letting urgency decide: a deadline-driven discount or a doorstep visit pushes a quick signature before any verification has happened. Slowing down to compare the same scope across vetted firms removes almost all of these errors.

• Comparing on headline price rather than scope, accreditation and guarantee together.
• Accepting a named accreditation without checking the official register.
• Treating a long guarantee as strong without confirming who backs it.
• Comparing quotes that cover different areas, materials or making good.
• Signing under time pressure before any independent check is done.

Comparing through Insulation Quotes Walsall removes the first checks for you, because the installers we connect you with are already vetted for the accreditations that matter. See our how-to-choose guide for the full process.