How we provided a five-option improvement roadmap for a period office building in Exeter city centre, enabling the client to transform their property from the lowest EPC band to the highest.
Energy Performance Direct was commissioned to carry out a full commercial energy assessment and provide a detailed Energy Advice Report for a period office building in Exeter city centre. The property comprises first and second floor office accommodation totalling 364.9 square metres, heated by a natural gas boiler with natural ventilation.
The baseline assessment revealed a G189 rating, placing the building firmly in the lowest EPC band. With MEES regulations requiring a minimum E rating for all commercial rental properties, the client needed a clear pathway to compliance along with options for achieving higher ratings to future-proof the property.
We provided five distinct improvement options, each building progressively on the previous, taking the building from G through E, D, C, B and ultimately to Band A. This gave the client the flexibility to choose the level of investment appropriate for their circumstances while understanding exactly what each option would deliver.
G189
Baseline Rating
A25
Achieved Rating
87%
CO2 Reduction
84%
Energy Reduction
The building presented several common challenges found in period commercial properties in Exeter and similar South West towns:
Natural gas boiler serving the entire building. Gas heating in commercial buildings carries a significant carbon penalty in SBEM calculations.
Uninsulated roof, walls and floors typical of a period building. Heat loss through the building fabric was substantial.
Original windows with high U-values contributing to both heat loss and solar gain issues.
Fixed lighting throughout was below modern efficiency standards, contributing to unnecessary electricity consumption.
We provided five progressive improvement options, each with precise SBEM-modelled figures. This approach gives the building owner complete flexibility to choose the right level of investment while understanding exactly what each option achieves.
Roof insulation alone is sufficient to achieve MEES compliance. This is the minimum investment required to legally let the property.
A comprehensive fabric-first and lighting approach that significantly reduces both heating demand and electricity consumption.
Switching from gas to efficient electric heating via heat pump technology delivers a major rating improvement. This option focuses purely on the heating system change.
Combining the heating system upgrade with roof insulation delivers Band B. This represents strong energy performance and positions the building well for potential future MEES tightening.
The complete transformation. All measures combined achieve the highest possible rating band, reducing emissions by 87% and energy use by 84% compared to baseline.
As part of the MEES compliance assessment, we conducted a detailed financial payback analysis for the roof insulation measure. This calculation is required to determine whether a MEES exemption can be claimed on the basis that improvements fail a 7-year payback test.
The 7-year savings exceed the improvement cost, meaning the measure passes the payback test and a MEES exemption cannot be claimed. The works must be carried out.
Insulation should be installed comprehensively with no gaps. Partially insulating a building can cause thermal bridging, condensation and damp issues. This is particularly important in period buildings where existing construction may be moisture-sensitive.
Making the building airtight will further improve costs, comfort and CO2 output. However, improved airtightness increases potential condensation risk. Passive or mechanical ventilation strategies should be considered. Pressure tests are recommended after insulation installation but before decorating to identify and address any gaps.
Phase 3 electrical upgrades are highly recommended to future-proof the building for heat pumps, EV charging, smart appliances and battery installations. As the grid decarbonises, electrically-heated buildings will achieve progressively better EPC ratings.
All advice provided is based on improved EPC scores and is impartial and independent of any installer or specific products. We always recommend obtaining 3 to 5 like-for-like quotes to gain an accurate understanding of practical and cost implications.
| Option | Rating | CO2 (kgCO2/m2/yr) | Energy (kWh/m2/yr) | CO2 Reduction |
|---|---|---|---|---|
| Baseline | G189 | 103.8 | 512.72 | - |
| Option 1 | E116 | 63.7 | 322.1 | 39% |
| Option 2 | D89 | 48.7 | 240.33 | 53% |
| Option 3 | C60 | 32.7 | 230.76 | 68% |
| Option 4 | B38 | 20.9 | 144.81 | 80% |
| Option 5 | A25 | 13.5 | 93.61 | 87% |
Even period buildings with a G189 baseline can achieve Band A through a well-planned combination of fabric improvements, efficient heating systems, modern lighting and careful specification.
Roof insulation alone can shift a G-rated building to Band E, achieving MEES compliance with a single improvement measure. For landlords under immediate compliance pressure, this is the fastest route.
Replacing a gas boiler with split AC units (heat pump technology) is one of the most impactful measures in SBEM calculations. The switch from gas to efficient electric heating can single-handedly deliver two or more band improvements.
A five-option approach gives building owners genuine flexibility. Not every property requires Band A, and understanding the cost-benefit of each step allows informed investment decisions.
Financial payback analysis is essential for MEES compliance. Where savings exceed improvement costs over seven years, a MEES exemption cannot be claimed and the works must be carried out.
Future-proofing with Phase 3 electrics, ventilation strategies and pressure testing should be considered alongside EPC improvements to protect the investment and avoid condensation issues.
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Our accredited assessors provide detailed EPC assessments with practical improvement roadmaps. Whether you need MEES compliance advice or a full improvement strategy, we can help.