Introduction to PAS
Definition of PAS and Its Growing Relevance
PAS is a specification standard developed in response to market demand, created quickly under controlled guidelines from the British Standards Institution (BSI). Unlike British Standards (BS), a PAS is not subject to the full consensus and periodic review of a BS, but it is often the precursor to one.
PAS standards are crucial for:
- Rapid industry alignment
- Establishing clear compliance pathways
- Supporting government initiatives like energy-efficiency grants
Why Is PAS Important Now?
With the UK housing stock among the oldest in Europe, energy retrofits are essential to meet climate targets. PAS provides a structured framework to ensure these retrofits are safe, high-quality, and energy-efficient.
What is PAS?
PAS stands for Publicly Available Specification. In the context of the UK’s built environment and sustainability regulations, it refers to standards developed by the British Standards Institution (BSI) in collaboration with key industry stakeholders. These documents serve as practical, fast-tracked standards to meet specific regulatory or market needs.
Crucially, PAS 2030 and PAS 2035 form the backbone of quality assurance in the retrofit of existing buildings to improve energy efficiency. With the rise of government-backed schemes such as ECO4, TrustMark registration, and increased focus on net-zero goals, understanding “what is PAS” has never been more critical for contractors, assessors, coordinators, and homeowners alike.
So, let’s delve deep and unravel the ins and outs of this essential UK standard.
PAS in the UK Context
The Role of the British Standards Institution (BSI)
The BSI acts as the principal organisation developing PAS in consultation with industry experts, government bodies, and private firms. Their aim? Ensuring that industry practices follow rigorous guidelines while also being practical and adoptable.
Who Uses PAS?
PAS standards are used by:
- Retrofit installers
- Domestic energy assessors
- Local councils and housing authorities
- Certification bodies
- Retrofit Coordinators and Designers
PAS 2030 Overview
Why PAS 2030 Was Introduced
PAS 2030 lays the groundwork for how energy-efficient measures (EEMs) should be installed in UK homes. It emerged to ensure that only certified professionals carry out installations eligible for government funding schemes.
Key PAS 2030 Requirements
Installers must:
- Be certified by a UKAS-accredited body
- Use appropriately trained operatives
- Follow strict documentation and record-keeping procedures
It aligns closely with the PAS 2035 framework and is essential for anyone involved in domestic retrofit.
Read the full PAS 2030 Guide →
PAS 2035 Explained
A Whole-House Framework for Retrofit Quality and Compliance
PAS 2035 is the UK’s definitive specification for the retrofit of domestic buildings. It’s more than a set of guidelines—it’s a structured, mandatory framework that outlines how energy efficiency improvements should be assessed, designed, delivered, and evaluated.
The standard was developed in response to concerns over the “single-measure retrofit” approach, which often led to unintended consequences such as mould, overheating, or increased energy use. PAS 2035 ensures a “whole-dwelling” retrofit strategy, where every aspect of the home is considered in a joined-up, holistic manner.
The PAS 2035 Retrofit Framework
At its core, PAS 2035 delivers a risk-based approach to retrofit. Each property is assigned a “risk pathway”—A, B, or C—depending on its complexity, occupancy type, and condition. These pathways determine the depth of assessment, oversight required, and post-installation checks. This methodical classification ensures that low-risk homes aren’t overburdened with admin, while high-risk homes get the detailed scrutiny they need.
A simplified breakdown of the PAS 2035 process includes:
- Occupant Engagement – understanding needs and behaviours
- Whole-Dwelling Assessment – examining energy use, ventilation, structure, and heritage
- Risk Assessment – selecting the proper risk pathway
- Retrofit Design – tailored specifications for energy efficiency upgrades
- Installation (via PAS 2030) – carried out by accredited installers
- Monitoring and Evaluation – performance analysis post-completion
Each stage must be carried out or signed off by individuals who hold specific roles, with clear qualifications and responsibilities.
The Five Key Roles in PAS 2035
PAS 2035 introduces a robust chain of accountability through six defined professional roles, each with distinct responsibilities and compliance obligations. These roles ensure that every stage of a retrofit—from initial advice to final evaluation—is carried out with professionalism, care, and compliance.
Retrofit Assessor
Role: Conducts the whole-dwelling assessment, gathering essential data that informs design and risk path selection.
Key Tasks:
Perform on-site surveys
Collect EPC data, thermal bridging information, and ventilation status
Record occupancy patterns and overall building condition
Tip: This role is foundational—errors here can misguide the entire retrofit process.
Retrofit Coordinator
Role: Oversees the project, ensuring that all work aligns with PAS 2035 requirements and is properly documented.
Key Tasks:
Validate designs and installer qualifications
Ensure appropriate risk pathway selection
Sign off documentation at each stage
Note: This role requires a Level 5 Diploma in Retrofit Coordination and Risk Management, reflecting its regulatory significance.
Retrofit Designer
Role: Develops bespoke technical solutions and selects suitable energy efficiency measures for each dwelling.
Key Tasks:
Produce detailed plans and technical specifications
Ensure synergy between measures (e.g., insulation, ventilation)
Tailor designs to dwelling type, condition, and risk path
Tip: Retrofit Designers often collaborate with architects and must ensure that all plans are feasible and safe.
Retrofit Installer
Role: (This role was previously implied—now clarified.)
Key Tasks:
Implement retrofit measures as specified in the design
Follow best practices and product standards
Work under oversight from the Retrofit Coordinator
Tip: Installers must be certified under a TrustMark scheme and follow the coordinator’s approved plan.
Retrofit Evaluator
Role: Measures the success of retrofit interventions by evaluating actual performance and resident feedback.
Key Tasks:
Conduct post-occupancy evaluations (POE)
Monitor key metrics such as indoor air quality and energy use
Provide data for continuous improvement in retrofit strategies
Tip: Evaluators ensure that lessons are learned and best practices are shared for future projects.
Differences Between PAS 2030 and PAS 2035
PAS 2030 and PAS 2035 are two interconnected but distinct specifications that play crucial roles in ensuring quality and compliance within energy efficiency retrofit projects. Understanding the distinction between them is vital for stakeholders aiming to deliver consistent and effective outcomes in building performance improvements.
Understanding Their Relationship
PAS 2035 is a management and oversight process. PAS 2030, on the other hand, is focused on the physical implementation of EEMs. In essence:
- PAS 2035 guides how work should be assessed and planned.
- PAS 2030 governs how the actual installation is carried out.
Why PAS Matters for Energy Efficiency
Linking PAS with Carbon Reduction Goals
PAS 2030 and PAS 2035 are essential to the UK’s mission to cut carbon emissions and meet net-zero targets by 2050. With homes responsible for around 14% of national CO₂ emissions, energy retrofits are a top priority.
The PAS framework ensures that retrofit works:
- Follow a structured, whole-house approach
- Use verified, low-carbon technologies
- Improve thermal efficiency without compromising air quality
Crucially, compliance with PAS is now required for schemes like ECO4 and SHDF, helping ensure government funds are used effectively to drive energy savings.
What’s Covered under PAS 2030?
Some compliant measures include:
- Loft and cavity wall insulation
- Energy-efficient boilers
- Solar PV installations
- Smart thermostats
In a nutshell: PAS standards turn good intentions into measurable outcomes—supporting the UK’s climate goals and creating warmer, healthier homes.
The Role of Retrofit Installers and Advisors
Responsibilities Under PAS 2035
Under PAS 2035, both retrofit installers and retrofit advisors play essential roles in ensuring projects meet compliance, safety, and performance standards.
Retrofit Installers
These are the professionals who physically implement energy efficiency measures—such as insulation, ventilation systems, or heat pumps—according to specifications outlined by the Retrofit Designer.
Key responsibilities:
- Work only if certified under PAS 2030
- Install according to design and risk pathway requirements
- Submit photographic and documentary evidence of completed work
- Cooperate with the Retrofit Coordinator for quality assurance checks
Tip: Installers must ensure all works align precisely with the risk assessment and approved designs to avoid invalidating the project’s compliance.
Retrofit Advisors
Advisors are often the first point of contact for occupants. Their role is primarily to guide, inform, and support householders through the retrofit journey.
Key responsibilities:
- Provide tailored advice about suitable retrofit options
- Communicate technical information in clear, accessible language
- Support the occupier in decision-making
- Facilitate engagement with the wider project team
Together, these roles ensure that PAS 2035 projects are both technically sound and occupant-focused, aligning delivery with high standards of quality, safety, and comfort.
ECO4 and PAS Compliance
Why It Matters for Funding
The UK Government’s Energy Company Obligation scheme—ECO4—is designed to improve the energy efficiency of low-income and vulnerable households. However, accessing this funding isn’t as simple as submitting a quote. To qualify, all retrofit work must strictly comply with PAS 2035 and PAS 2030 standards.
That means:
- Assessment, design, and coordination must follow PAS 2035
- Installation must be carried out by PAS 2030-certified professionals
- All documentation must be audit-ready and aligned with TrustMark requirements
Without full compliance, even high-quality retrofit work becomes ineligible for ECO4 funding—regardless of its performance outcomes. This protects public funds and ensures consistency, safety, and long-term impact across projects.
In short: If you’re not PAS-accredited, you’re not getting ECO4 funding. It’s that black and white.
Step-by-Step Guide to PAS 2030 Compliance
From Application to Audit
1. Evaluate Readiness and Qualifications
Assess whether your business meets the PAS 2030 standard requirements, including technical competence, quality control processes, and installation practices.
2. Select a UKAS-Accredited Certification Body
Choose a reputable and UKAS-accredited body to guide and assess your compliance process.
3. Gather Required Documentation
Prepare all necessary documents such as quality management procedures, installation records, and training certifications.
4. Undergo Initial Audit
Your chosen certification body will conduct a full audit, reviewing documentation and inspecting installation work for compliance.
5. Address Any Non-Conformities
If issues are identified, implement corrective actions promptly and submit evidence to satisfy the certification body.
6. Maintain Compliance Annually
Continue to meet PAS 2030 standards with yearly surveillance audits and updates to practices and documentation as required.
Costs Associated with PAS Accreditation
What Will It Cost You?
While prices vary depending on the certification body and your business scope, expect initial costs to range between £2,000–£5,000, plus annual surveillance fees. Investing in proper training and documentation will reduce long-term costs.
Breakdown of PAS 2030 Certification Costs →
Documentation & Evidence Requirements
Proof is Everything
When applying for PAS 2030 or PAS 2035 accreditation, solid documentation is non-negotiable. You’ll need to present:
- Risk assessments for each property
- Design documentation prepared by a Retrofit Designer
- Install reports, signed off by qualified personnel
- Post-install evaluations
- Client handover documents
For Retrofit Coordinators, it’s essential to use a recognised data warehouse or platform that integrates with TrustMark, ensuring your records remain auditable and retrievable.
Tip: Use digital project management software to keep all your evidence organised and timestamped. This speeds up audits and builds trust.
Benefits of Being PAS Accredited
Unlocking Opportunity and Trust
Here’s what PAS certification brings to the table:
- Access to Government Schemes: Most notably, ECO4
- Market Credibility: Being PAS-accredited instantly boosts your profile with clients and partners
- Better Quality Control: The process itself encourages more reliable outcomes
- Competitive Advantage: Your quotes become more attractive in public and private tenders
Think of PAS like a seal of trust. It doesn’t just tick boxes—it speaks volumes.
Challenges and How to Overcome Them
Yes, It Can Be Daunting—But Here’s Help
Many businesses stall at the “preparation” stage. Common roadblocks include:
- Misunderstanding retrofit roles
- Lack of trained assessors or coordinators
- Poor documentation habits
- Missed updates in the latest PAS guidelines
How to overcome:
- Attend PAS workshops
- Subscribe to TrustMark and BEIS newsletters
- Use internal audits to spot gaps before certification bodies do
Third-Party Certification Bodies
Who Can Certify Your PAS Compliance?
Only UKAS-accredited certification bodies can issue official PAS 2030 certification. Examples include:
- Simply Certification
- NICEIC
- Elmhurst Energy
- Stroma Certification
Ensure they offer PAS 2035-compliant services, especially if you’re managing full retrofit projects.
Monitoring and Evaluation in PAS 2035
The Retrofit Evaluator’s Crucial Role
This stage determines whether the retrofit has met its objectives. Monitoring may involve:
- Thermal imaging
- Air tightness testing
- Occupant feedback
- Energy consumption analysis
The data collected helps refine future projects and ensures continual improvement—an essential loop in PAS 2035.
The Retrofit Process from Start to Finish
A Clear, Repeatable Framework
From first assessment to final evaluation, here’s how a PAS-compliant project flows:
- Initial Retrofit Advice
- Whole Dwelling Assessment
- Risk Pathway Selection
- Design & Specification
- Installation
- Post-installation Evaluation
Each step is governed by strict criteria and assigned to a specific qualified individual. This guarantees accountability across the board.
How to Choose the Right Retrofit Assessor
It’s Not Just About Cost
Look for:
- PAS-recognised training (e.g., Retrofit Academy)
- Experience with similar properties
- Good feedback from clients
- Ability to produce reports in digital formats
Don’t be tempted by shortcuts—an inadequate assessment could invalidate your entire project’s compliance.
Training and Qualifications Needed
Get Qualified, Get Compliant
Mandatory training includes:
- Level 5 Diploma in Retrofit Coordination & Risk Management
- TrustMark-approved certifications
- Continuous Professional Development (CPD)
Look into providers like The Retrofit Academy, who offer nationally recognised training aligned with PAS 2035.
Common Pitfalls and Compliance Gaps
Even Good Installers Get It Wrong
Avoid these common traps:
- Using outdated PAS versions
- Skipping post-install checks
- Mislabelled documentation
- Failing to record customer consent
Hint: Keep a PAS compliance checklist handy on every job site. It’ll save your skin more than once.
PAS in Future Legislation
The Role of PAS in Net-Zero Britain
As we inch closer to 2050 net-zero targets, expect PAS standards to evolve. There are strong indications that:
- PAS 2035 may integrate with smart home technology standards
- A future “PAS 2040” may emerge for non-domestic retrofit settings
- More emphasis on occupant health and indoor air quality
How to Stay Updated with PAS Changes
Stay Ahead of the Curve
To stay current:
- Join mailing lists from BSI, BEIS, and TrustMark
- Follow LinkedIn updates from Retrofit Academy and Brighter Compliance
- Attend annual compliance conferences and webinars
FAQs About What is PAS
What does PAS stand for?
PAS stands for Publicly Available Specification, a UK-developed industry standard created by BSI.
Do I need both PAS 2030 and PAS 2035?
Yes. PAS 2035 governs retrofit planning, and PAS 2030 covers installation standards.
Can I get funding without PAS accreditation?
No. Most government-backed funding schemes require full PAS compliance.
How long does accreditation take?
Expect 4–8 weeks, depending on readiness and documentation.
Is PAS 2035 mandatory for all homes?
For ECO-funded or TrustMark projects, yes. For private work, it’s highly recommended but not legally required.
Where can I learn more about PAS 2030 costs?
Visit the PAS 2030 Cost Guide.
Conclusion
So, what is PAS? It’s not just a buzzword in the world of retrofitting—it’s the gold standard for ensuring your energy-efficient work is credible, fundable, and future-ready. With PAS 2030 and PAS 2035 at its core, the PAS framework provides the clarity, consistency, and control needed to meet the UK’s ambitious retrofit goals. Whether you’re a homeowner, contractor, or policy advisor, embracing PAS is a step toward sustainable housing and long-term energy savings.
