Case Study 3 – Small Office EPC In Bedford

office unit commercial epc bedford


A commercial epc was required for a converted building to an office in Bedford.

The unemployment rate in the Bedford area stands at 4.2% which is higher than the eastern regions average of 3.5, according to the Office of National Statistics 2021 census.

The local authority, Bedford Borough Council, want to attract new businesses and employers to the area.

A detailed study was carried out by the Council in 2023 to identify opportunities and challenges that face the area.

One of the biggest future growth of employment is in warehousing and logistics and this is mainly due to the continuing growth of e-commerce.

It also identified that Bedford Council has less available land to accommodate these types of businesses compared to some of it’s neighbours.

Bedford’s advantageous positioning within the Golden Triangle, encompassing Oxford, Cambridge, and London, as well as its location along the Ox-Cam Arc, presents the Borough with a unique chance to draw investments and play a pivotal role in fostering regional economic expansion.

Whilst the local authority is strategically planning for the long term future, there are many small scale units being adapted to provide additional space for smaller local businesses.

In this case study, we look at one such unit and the challenges it faced in achieving the Minimum Energy Efficiency rating of an E during the process.

Project Overview

The building needing the EPC was a small single storey outbuilding at the rear of a domestic house.

The building was adapted to provide office space for a small business. We were originally contacted by the estate agent who would be managing the property.

They wanted an emergency commercial EPC because a tenant was moving in the following week.

Because the project was small and we were local, we arranged the EPC visit the next day and completed the EPC that day and that’s where the difficulties started.

Because the building didn’t meet the MEES standard of an E and only rated a poor G155, it meant that it couldn’t be let.

EPC Process


The building was a small unit of only 28m2 and it had less than 5 rooms/zones so it came within our minimum price of £198.

The Site Visit

A site visit was carried out.

The main purpose of the site visit is to obtain information and photographic evidence about the:

  • Building fabric construction type
  • HVAC system
  • Glazing type and dimensions
  • The activity of the zones within the building
  • The type of lighting
  • The provision for hot water

A period of 20 minutes was spent on site. 

Off site data entry

Once off site, the data obtained has to be entered into the SBEM software.

The 1st step involves zoning the floor plans.

This was a simple project and below is the zoning plan of the project.

zoning plan office in bedford

Summary of elements in the building

Total Zones for the project
Building fabric construction type
HVAC system
Glazing type and dimensions
The type of lighting
The provision for hot water
Solid walls drylined internally, solid floor, flat roof. There was no evidence that insulation was installed to any of these areas.
Electric room heaters
Double glazed windows with unknown date
CFL bulbs
Instantaneous hot water appliance

Results and Achievements

After reviewing the data and running calculations, the software produced a poor EPC rating of a G 155.

A draft EPC was sent to the agents, informing them that it didn’t meet the minimum energy efficiency standards. The landlord was subsequently notified.

The landlord claimed that building control approved the conversion and assured that all insulation and building regulations were met. I requested written documentation from the builder regarding the insulation used.

The builder verbally confirmed the work but didn’t provide written details, causing frustration for the landlord who feared losing the tenant.

As a non domestic energy assessor, we require photographic or documentary evidence to support the data entry. Without evidence, it defaults to a worse-case scenario based on the building’s age. Sometimes an inexperienced assessors may feel forced or even knowingly “cook the books” and enter data that can’t be substantiated.

Audits can lead to EPC ratings being downgraded if unsupported data is found, causing future problems for landlords.

Since no documentation was provided by the builder, we conducted inspections. Unfortunately, no insulation was found behind the plasterboard on the walls or in the flat roof, confirming the poor EPC rating.

This left an angry and disappointed landlord who had spent £5,000 on refurbishments but couldn’t let the building due to its low rating.

The Solution

  After the shock of finding out the true position, the landlord asked us for detailed solutions of how to get the building to reach the required E rating. We drew up a proposal which would improve the rating from a G to an E and consisted of 3 steps:
  1. Improve the thermal values of the walls from a u-value of 1.7 W/m2K to 0.28 W/m2K (the lower the u-value the better the thermal efficiency). This could be achieved by fitting a Kingspan 108, 62.5mm or equivalent insulated plasterboard to the internal walls.
  2. Improve the thermal value of the flat roof from a u-value of 2.8 W/m2K to 0.40 W/m2K. This could be achieved by fitting 100mm insulation to the flat roof also ensuring that at least a 50mm air gap was maintained above the insulation.
  3.  Change all lighting to LED lighting.

If these steps were implemented on the project, then the EPC rating would be an E 108 which would meet the minimum energy efficiency standards and the building could then be let.

Builders often, when given a spec, often look for cheaper ways to achieve an outcome and sometimes install products that don’t meet the required thermal values. Therefore, It was stressed to the landlord that these specify values had to be achieved or she could stand the risk of wasting more money and still not achieve the desired outcome.

The landlord put us directly in touch with her contractors Kefford Plumbing Services in Renhold, Bedford who would be carrying out the work. We liaised with Gary there, detailing what was required. Gary wanted to fit a Celotex PL4000 board for which he got a better price and we confirmed that the a Celotex PL4060 board of 72.5mm would achieve the same result and would be fine.

A good working relationship was developed between us, the landlord and Kefford Plumbing Services. Once the work was in progress, Gary invited me down to gather the photographic evidence to confirm that things were fitted as specified.

insulated plasterboard thickness

Insulated plasterboard thickness

internal wall insulation

Room internal wall insulation

insulated flat roof

Insulated flat roof

Happy with everything, we then updated the EPC and the ratings are shown below.

epc rating office in bedford

The second part of the EPC rating shows what the building would rate if it were new and how it compares to other typical properties of that age and size and activity, this is shown below.

office epc bedford comparison

Project Summary

The cost to the landlord to get the building to an E rating was just over £3, 000 as shown on the invoice below.

builders invoice for epc upgrade work

A copy of this invoice could be used for future energy performance certificates as documentary evidence of the work carried out.

The landlord was also given further advice of how to reach to a C if and when the minimum energy efficiency standard was raised. A rating of C could be achieved by changing the panel electric heaters to an Air Con multi split system.

Although the project was small it still involved a lot of additional work to achieve the E rating. Normally we would charge for the additional advice and revisits to the property. However, because the landlord was under severe pressure and time restrains, we waived any additional costs.

If you require a commercial EPC in Bedford contact us on 01234 294873 or by email to [email protected]


Submit a Comment

Your email address will not be published. Required fields are marked *

Rickie Dickson
Written by Rickie Dickson

Rickie Dickson is an experienced and qualified domestic and non domestic energy assessor. He helps homeowners and businesses in all matters relating to energy efficiency, from meeting building regulations compliance to improving a property’s energy rating score.