The methodology we use for VolDECs
VolDECs use the same methodology as statutory Display Energy Certificates (DECs) and provide a similar certificate layout with an A-G scale, but that’s where the similarity ends. VolDECs take all the good features of statutory DECs and make them better, easier and more informative while also allowing tailoring for each sector and individual client requirements.
Better benchmarking
VolDECs use ECON19 benchmarks for offices while statutory DECs use a single CIBSE TM46 benchmark. This has the advantage of providing multiple benchmarks dependent on the building type instead of just a ‘one shoe fits all’ approach. Using a similar approach, VolDECs will be developed for other sectors.
Enhanced rating scale
The traditional A-G rating scale used in statutory DECs has been extended to include G1 to G4 ratings. This has the advantage of providing low-ranking buildings with a more defined rating in order to encourage improvement. VolDECs also include a U (Unclassified) rating for buildings where performance or data is exceptionally poor.
Improved data quality
Uniquely, VolDECs include a certificate quality rating: HIGH, MEDIUM and LOW, to encourage improvements in data quality. In some cases this encourages clients to go back and assess their data rather than simply trust a less robust rating.
Landlord/tenant split
By separating out the tenant energy outputs from those produced by the common parts of a building, property owners/operators are provided with cost-effective, user-friendly energy ratings for just those areas of an asset that are within their control to improve.
| Statutory DEC | VolDEC | |
| Methodology | Produced using the methodology described in CIBSE TM47 | Produced using the methodology described in CIBSE TM47 |
| Benchmarks | Uses CIBSE TM46 benchmarks. This provides only one benchmark for all office types | Uses ECON19 benchmarks for offices. This provides four different office types and energy is broken down by end use for each type |
| Rating scale | A-G rating scale | Uses G1-G4 and U ratings, thereby providing more granular information for poor performing buildings |
| Data quality | No specific data quality checks | Uses a High/Medium/Low certificate data quality rating |
| Landlord/tenant split | Unable to provide a separate landlord/tenant DEC in the same building | Uses the granular energy breakdown in ECON19 to provide composite landlord and tenant benchmarks for seven different building scenarios |
VolDEC development
VolDECs are now being further developed to:
- Include other elements such as waste and water
- Provide individual (floor by floor) VolDECs
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