Our services

Services built around compliant delivery

From retrofit coordination to compliant retrofit delivery services, Retrofit OS supports teams delivering energy efficiency at scale, with software designed for industry by the industry, we are here to support no matter what.

Core services

Our primary delivery services for compliant retrofit programmes.

Retrofit Assessment

Structured retrofit assessments that capture dwelling condition, occupancy and improvement options ready for PAS 2035 coordination and programme funding.

Retrofit Coordination

End-to-end PAS 2035 coordination with all the experience in-house to deliver quality, linking assessors, designers and installers so milestones, evidence and handovers stay aligned.

Energy Modelling

RdSAP-led property level energy modelling and scenario comparison so you can understand savings, compliance boundaries and package trade-offs before committing work on site.

Retrofit Design

Fabric-first retrofit design support, from measure selection and sequencing to specifications that installers can price and deliver against PAS expectations.

Trustmark Lodgement to Data Warehouse

Lodgement-ready TrustMark submissions and data warehouse uploads organised for scheme rules, consistency checks and a clean audit trail.

Retrofit/PAS2030/2035 Advice

Strategic advice on PAS 2030 and PAS 2035 roles, pathways and governance so programme design and procurement decisions stay proportionate and defensible.

Additional sub services

Extended technical and compliance services available to support specific programme needs.

Pre/Post EPR Generation

Energy Performance Reports generated before and after works to evidence regulatory performance and support programme compliance paperwork.

EPC Generation

RdSAP-based EPC production for stock profiling, procurement windows and compliance reporting across domestic retrofit portfolios.

U-Value Calculations

Transparent U-value calculations for building elements so targets in specifications match declared materials and construction detail.

PSI Value Calculation (Thermal Bridging)

PSI-value (thermal bridging) calculations to quantify junction losses and support compliant SAP inputs and fabric specifications.

FRSI Calculations

Facade reflective solar index (FRSI) calculations where overheating and solar gain drive retrofit design choices on exposed elevations.

Air Tightness Testing

On-site air permeability testing with results reported for compliance checks, PAS evidence and handover documentation.

Chartered Surveyors Report

RICS-style chartered surveyor reporting where defects, liabilities or stock condition affect retrofit procurement and programme risk.

Condensation Risk Analysis

Condensation risk analysis for retrofit build-ups—interstitial and surface risks—to validate insulation and vapour strategies before works are locked in.

Heat Loss Calculations

Room-by-room or zone heat loss calculations to size heating systems correctly after fabric upgrades and ventilation changes.

PAS2035 Project On-Site Visits

PAS 2035–aligned site visits to verify progress, evidence quality and coordination touchpoints during delivery.

PIBI Pre-Approvals

Project Integrator / Built Intelligence–style pre-approvals support where scheme gateways require documented sign-off before proceeding.

PAS 2035 Compliance Audits

Independent-style PAS 2035 compliance audits sampling projects for documentation completeness, consistency and scheme readiness.

Ventilation Strategy Design

Ventilation strategies for retrofit—including infiltration changes—that balance indoor air quality, moisture safety and noise.

Moisture Risk Management Plans

Moisture risk management planning where invasive retrofit increases interstitial risk—documenting monitoring and contingencies.

Thermal Imaging Surveys

Thermal imaging surveys to reveal insulation continuity defects, thermal bridging and air leakage paths before or after works.

Airtightness Strategy & Detailing

Airtightness strategies and junction detailing so targets are achievable on site—not only written into specifications.

Contractor Design Reviews / Value Engineering

Design reviews and value engineering sessions with contractors to align specification, cost and buildability without compromising compliance.

Technical Specification Writing (for tenders)

Tender-ready technical specifications that bundle measures, standards and acceptance criteria for retrofit procurement.

Clerk of Works / Quality Assurance Inspections

Clerk of Works and QA inspections during retrofit delivery—checking workmanship against specification and capturing compliant evidence.

Building Physics Modelling (advanced WUFI-style analysis)

Hygrothermal (e.g. WUFI-style) modelling for complex assemblies where steady-state condensation checks are insufficient.

Training / CPD Workshops for contractors or clients

Bespoke training and CPD on PAS retrofit delivery, evidence quality and programme governance—built around your teams’ live challenges.

We support a range of organisations in the retrofit industry

Choose your role and follow a service path designed around your delivery responsibilities.

I’m a principal contractor

Coordinate delivery teams, measures and timelines from one place
Keep compliance evidence organised across each project stage
Reduce delays with clearer reporting and handover readiness

I’m a local authority

Assess programme performance with transparent project visibility
Monitor standards, evidence quality and compliance outcomes
Support residents with structured retrofit delivery pathways

I’m a social housing provider

Plan improvements across housing stock with practical service support
Track delivery progress and documentation in one environment
Strengthen resident outcomes while maintaining compliant records

Turnkey retrofit projects include client dashboards

When Retrofit OS takes on a turnkey retrofit project, your organisation does not only get delivery resource, you get access to our platform so you can see progress and outcomes as they happen.

Dashboards and reporting are included for your teams and stakeholders, so programme visibility stays aligned with field delivery without relying on ad-hoc spreadsheets or manual updates.

What you can use alongside delivery

Live dashboards — track jobs, milestones and evidence completeness across the programme in one place.
Structured reporting — exports and summaries suited to governance, partners and audit-ready reviews.
Shared visibility — delivery and client teams work from the same picture of status, reducing rework and query loops.

Customers we have worked with

Some of the organisations we have supported in delivering decarbonisation services.

Experienced de-carb services team

Our de-carbonisation services team brings the practical experience and technical knowledge needed to support delivery from planning through to completion.

We work closely with delivery partners to keep projects moving, maintain quality standards and ensure compliant outcomes at scale.

✓

14,000+

Projects supported and delivered over the past 6 years

Frequently asked questions

Common questions about our retrofit delivery services, PAS compliance and programme support.

You can look into becoming a certified Retrofit Coordinator through The Retrofit Academy.

To use the ECO Surv platform, you must become an accredited Retrofit Coordinator. ECO Surv recognises several accreditation bodies, including:

- Stroma Certification
- Elmhurst Energy
- Quidos

If you are currently accredited with a body not recognised by ECO Surv and want to use the ECO Surv platform, you must also get accredited with either Elmhurst Energy or Quidos.

Yes, you must be PAS 2035 accredited to use the ECO Surv platform. ECO Surv says they can point users in the right direction if they need support with this. For jobs created after March 2025, users must be accredited to PAS 2035:2023. The platform supports both PAS 2035 revisions, depending on the scheme being worked under.

Yes. ECO Surv states that this is a common misconception. You can be accredited with more than one accreditation body to find work as a Retrofit Coordinator. For example, if you are accredited with a body not recognised by ECO Surv but want to lodge through ECO Surv, you can also become accredited with a recognised body such as Elmhurst Energy or Quidos.

No. ECO Surv states that you cannot be removed by TrustMark for holding more than one accreditation from an accreditation body.

ECO Surv says that by joining its Retrofit Coordinator service, users get access to its portal and mobile applications. The mobile apps allow Retrofit Assessors and Coordinators to capture information in the field. The workflow is based on the project's PAS risk path and is determined by the mobile app PAS 2035 risk route assessment. The project can then be submitted to the ECO Surv portal for validation, sign-off, installation, and lodgement to the TrustMark Data Warehouse through the user’s preferred accreditation scheme provider.

Users are directed to contact the ECO Surv team via the Contact Us page by filling out the form, after which a team member will respond.

Not sure where to start?

Tell us about your scheme mix and delivery model— we will recommend a sensible path across platform and services.

Speak to our team