Insulation Installer Job Margin 2025/26
Calculate margin on insulation installation jobs in the UK — cavity wall, loft, underfloor or external wall insulation (EWI). Model ECO4-funded projects (where the energy supplier pays) versus private-pay jobs to understand your true profitability per measure.
Key Inputs
- Insulation type: cavity wall / loft (blown or roll) / underfloor / EWI (solid wall)
- Property type and size (1-bed flat to 4-bed detached)
- Material cost (insulation product, fixings, render for EWI)
- Labour days at day rate
- Equipment hire or amortised cost (blowing machine, cherry picker for EWI)
- PAS 2030 certification overhead amortised per job
- TrustMark registration overhead amortised per job
- Revenue source: ECO4 funded (energy supplier pays) or private customer
What You'll Get
- Total material cost
- Total labour cost
- Total job cost
- ECO4 payment received or private retail price
- Gross profit
- Gross margin percentage
Important Notes — 2025/26 Rates & Caveats
ECO4 payment rates for insulation measures are set by energy suppliers and vary — typical ECO4 measure values: loft insulation £500–£1,500; cavity wall insulation £800–£1,800; EWI (solid wall) £8,000–£18,000 per property. Private insulation prices: loft insulation £300–£600; cavity wall £500–£1,200; EWI £8,000–£20,000. PAS 2030 certification is mandatory for ECO4 work. ECO4 installers must also be TrustMark registered. Margins on ECO4 work vary significantly by energy supplier contract and volume commitments. EWI jobs involve the most risk (scaffold, render failure, fire safety compliance for high-rises).
Frequently Asked Questions
What is the cost of external wall insulation (EWI) in the UK?
External wall insulation (EWI) for a solid wall UK property typically costs £8,000–£20,000+ depending on property size, render system choice and access requirements. Scaffold costs alone can be £1,500–£3,000 for a typical semi-detached. EWI is most cost-effective on large solid-wall properties where cavity wall insulation is not possible. Under ECO4, energy suppliers fund EWI for eligible fuel-poor households — the installer receives a payment from the energy supplier rather than the homeowner.
What certifications do insulation installers need for ECO4?
ECO4 insulation installers must be PAS 2030:2019 certified (the installation quality standard) and TrustMark registered. PAS 2030 certification is obtained through a UKAS-accredited certification body (BBA, BSI, KIWA, etc.). TrustMark registration requires passing a quality assessment and agreeing to the TrustMark Code of Practice. For multi-measure projects, the project must also be overseen by a PAS 2035 Retrofit Coordinator. Failure to hold these certifications means the installer cannot legally receive ECO4 funding.
Is cavity wall insulation still a good investment for UK homeowners?
Cavity wall insulation is one of the most cost-effective energy efficiency measures available in the UK. For a typical semi-detached with unfilled cavity walls, insulation costs £500–£1,200 and saves approximately £200–£350/year on energy bills (based on 2025/26 energy prices). Payback is typically 2–5 years for private-pay customers. Eligibility for ECO4 or GBIS funding makes it free for many households. However, properties with exposed walls, high rainfall or existing moisture problems may not be suitable — a survey is always required.
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