At On Power Ltd, we provide fully accredited Energy Performance Certificates (EPCs) and Retrofit Assessments, giving our customers complete confidence that every survey, calculation, and recommendation is carried out to the highest recognised industry standards.

We operate under the accreditation of ECMK and are aligned with the government-endorsed TrustMark quality scheme, ensuring all of our work is compliant, consistent, and professionally verified.

Accredited & Compliant Assessments

All Energy Performance Certificates (EPCs) must be produced by qualified assessors who are members of an approved accreditation scheme such as ECMK  . This ensures that assessments are carried out using regulated methodologies, approved software, and strict quality controls.

At On Power Ltd, our EPC surveys are conducted with precision and professionalism, providing an accurate representation of your property’s energy efficiency, along with clear recommendations for improvement.

What is an EPC?

An Energy Performance Certificate (EPC) provides a detailed overview of your property’s energy performance, including:

  • Current and potential energy ratings

  • Estimated energy costs

  • Carbon emissions data

  • Recommendations for improving efficiency

Whether you are selling, renting, or simply looking to improve your home, an EPC is a vital first step in understanding your property’s performance.

Retrofit Assessments (PAS 2035 Compliant)

In addition to EPCs, we carry out full Retrofit Assessments in line with PAS 2035, the UK’s official framework for domestic energy efficiency improvements.

Retrofit Assessments go far beyond a standard EPC. They take a whole-house approach, assessing not just the building itself, but also how it is used, occupied, and heated. 

Our assessments include:

  • Detailed property condition surveys

  • Occupancy and lifestyle assessments

  • Ventilation and moisture risk analysis

  • Thermal performance and heat loss calculations

  • Review of existing insulation and heating systems

The data collected forms the foundation for any future energy upgrades, ensuring that improvements are safe, effective, and tailored to the property.

Working to TrustMark Standards

All of our retrofit work aligns with the TrustMark framework — the UK Government-Endorsed Quality Scheme for work carried out in and around the home.

TrustMark ensures that registered businesses are:

  • Thoroughly vetted and quality checked

  • Compliant with industry regulations

  • Committed to high standards of customer service  

For our customers, this means complete peace of mind that all assessments are carried out professionally, ethically, and to nationally recognised standards.

The Importance of Accuracy & Consistency

Energy assessments are not just about ticking boxes — they form the basis of major decisions around your home, your investment, and your future energy costs.

That’s why at On Power Ltd, we ensure:

  • All surveys follow strict industry methodologies

  • All calculations are carried out using approved systems

  • All data is consistent with governing body guidelines

  • All reports are clear, transparent, and easy to understand

Retrofit Assessors play a critical role in collecting accurate data on buildings, which is then used to design effective energy improvements and ensure long-term performance  .

A Complete End-to-End Solution

What sets On Power Ltd apart is our ability to combine assessment and installation.

We don’t just identify opportunities — we help you act on them.

From your initial EPC or Retrofit Assessment through to:

  • Solar PV installation

  • Battery storage

  • Air Source Heat Pumps

  • Heating upgrades

We provide a fully integrated service, ensuring everything works together efficiently and compliantly.

Why Choose On Power Ltd?

  • ECMK accredited assessors

  • TrustMark-aligned standards

  • PAS 2035 compliant retrofit assessments

  • Accurate, reliable, and professional reporting

  • End-to-end energy solutions under one roof

Peace of Mind, Guaranteed

When you choose On Power Ltd, you are choosing a company that works to the highest recognised standards in the UK energy sector.

Our assessments are not only compliant — they are designed to give you clarity, confidence, and a clear path forward.

On Power Ltd — Trusted assessments. Smarter energy decisions. Complete peace of mind.