What is a Retrofit Assessment?

What is a Retrofit Assessment and How Much Does it Cost?

Before you can plan a retrofit programme for a commercial property, you need to understand what work is required and what it will cost. That understanding comes from an assessment, but the term "retrofit assessment" covers a wide range of services, from a basic EPC costing a few hundred pounds to a comprehensive RICS building survey costing several thousand. This guide explains the different types, what each delivers, and how automated scenario modelling from platforms like CrowAgent compares.

Types of retrofit assessment

There is no single standardised product called a "retrofit assessment" for commercial property. Instead, there are several distinct types of assessment, each with a different scope, methodology, and price point. Understanding the differences is essential for choosing the right level of assessment for your needs.

Energy Performance Certificate (EPC)

The EPC is the most basic form of energy assessment for commercial property. It is a legal requirement for any property being sold or let, and it provides a rating from A (most efficient) to G (least efficient) based on the building's carbon dioxide emissions per square metre.

For non-domestic (commercial) property, the EPC is produced using the Simplified Building Energy Model (SBEM) methodology. A qualified non-domestic energy assessor visits the property, collects data on the building fabric, heating and cooling systems, lighting, and hot water provision, and runs the SBEM calculation to produce the rating.

Every EPC comes with a recommendations report that lists the assessor's suggested improvements and their estimated impact on the EPC score. This is useful as a high-level indicator, but it is not a detailed specification, it does not include costs, and the estimated score improvements are based on generic assumptions rather than a detailed analysis of the specific property.

Typical cost: £200 to £500 for a standard commercial property. Larger or more complex buildings (multi-unit, mixed-use, or above 5,000 sq ft) can cost £500 to £1,000.

Energy audit

An energy audit goes beyond the EPC by providing a more detailed analysis of the building's energy consumption and identifying specific opportunities for improvement. Energy audits can range from a desk-based review of energy bills and building data (sometimes called a Level 1 audit) to a detailed on-site survey with measurement and monitoring (Level 2 or Level 3).

A good energy audit for a commercial property will include:

• Analysis of historical energy consumption data (gas and electricity bills)
• On-site inspection of building fabric, heating, cooling, ventilation, and lighting
• Identification of energy-saving measures with estimated costs and payback periods
• Prioritised recommendations based on cost-effectiveness

Energy audits are typically carried out by qualified energy consultants, often members of the Energy Institute or holding CIBSE (Chartered Institution of Building Services Engineers) qualifications.

Typical cost: £500 to £1,500 depending on building size and audit depth. A Level 1 desk-based audit starts around £500; a Level 2 audit with on-site survey and measurement typically costs £800 to £1,500.

RICS building survey with energy focus

For properties where the retrofit programme is likely to be substantial, involving structural changes, external wall insulation, glazing replacement, or heating system overhaul, a full building survey by a RICS (Royal Institution of Chartered Surveyors) qualified surveyor provides the most comprehensive assessment.

A RICS survey with an energy focus will cover:

• Detailed assessment of the building structure and fabric condition
• Identification of defects that must be addressed before or alongside energy improvements
• Specification of retrofit measures with detailed cost estimates
• Assessment of planning constraints (listed building, conservation area, permitted development rights)
• Advice on sequencing of works and potential disruption to tenants

Typical cost: £1,000 to £2,000 or more for a standard commercial property. Complex or large buildings can exceed £2,000.

What to expect from the assessment process

Regardless of which type of assessment you commission, the process typically follows a similar pattern:

1. Initial data gathering: The assessor will request floor plans, previous EPC data, energy bills, lease information, and any previous survey reports.
2. Site visit: For anything beyond a desk-based audit, the assessor will visit the property to inspect the building fabric, services, and systems. For occupied properties, this requires coordination with tenants.
3. Analysis and modelling: The assessor analyses the data, runs energy models, and identifies improvement measures.
4. Report delivery: You receive a written report with findings, recommendations, estimated costs, and projected EPC improvements.

Turnaround times vary. A basic EPC can be completed within a week of the site visit. A detailed energy audit typically takes two to four weeks. A full RICS survey can take four to six weeks, particularly if there are access constraints or the building is complex.

How CrowAgent's scenario modelling compares

CrowAgent Core is not a replacement for a professional on-site assessment. It serves a different purpose: automated triage and scenario modelling at portfolio scale.

When you enter a property postcode into CrowAgent Core, the platform retrieves the current EPC data from the MHCLG non-domestic register and runs an automated Band C (proposed) gap analysis. It then generates three retrofit scenario costings, minimum cost, balanced, and comprehensive, each with an estimated EPC score improvement and a net present value (NPV) calculation using the HM Treasury Green Book discount rate of 3.5%.

The costings are based on current market rates for common commercial retrofit measures and are updated quarterly. They are indicative figures designed to help you prioritise which properties need professional assessment, not to replace the detailed specification that a qualified consultant provides.

Choosing the right assessment level

The right type of assessment depends on the property, the compliance gap, and the likely complexity of the retrofit programme:

• Property is Band D, close to the C threshold: A new EPC with recommendations report may be sufficient. The improvement measures are likely to be straightforward (LED lighting, minor insulation, BMS optimisation).
• Property is Band D or E, significant gap to Band C (proposed): Commission an energy audit to identify cost-effective measures and their expected impact on the EPC score.
• Property is Band E, F, or G with structural or heritage constraints: Commission a full RICS survey to understand the building condition, planning constraints, and the feasibility of major fabric improvements.
• Portfolio of 10+ properties with mixed bands: Use automated triage (CrowAgent Core) to identify which properties need which level of assessment, then commission accordingly.

Do not over-specify assessments for simple properties, and do not under-specify them for complex ones. The goal is to match the depth of assessment to the complexity of the compliance challenge. A £200 EPC is sufficient for a modern office that needs LED lighting to reach Band C (proposed). A £2,000 RICS survey is warranted for a 1970s industrial unit with asbestos concerns and conservation area restrictions.