What is an OCDEA?

The accredited assessor who signs off new-build dwellings for Part L

An OCDEA - On Construction Domestic Energy Assessor - is the accredited UK professional who signs off new-build dwellings for Part L compliance. They run the SAP calculation, review the Appendix B photographic evidence, and produce the BREL report that Building Control signs off before handover.

If you're a builder on a new plot, the OCDEA is the assessor you'll deal with. They are the gate between a finished building and sign-off.

What an OCDEA actually does

For every new dwelling, an OCDEA will:

  1. Run design-stage SAP. Before construction starts, they calculate the expected energy performance from the drawings and specifications. This goes to Building Control with the Part L application.
  2. Advise on changes during build. If the specification shifts - a different boiler, a different insulation product, a change to window specification - the OCDEA updates the SAP model accordingly.
  3. Review Appendix B photographic evidence. Once construction progresses, the OCDEA checks the photos coming in from site: every required section photographed, every photo GPS-tagged and dated, every plot kept separate.
  4. Run as-built SAP. When the dwelling is finished, they update the SAP calculation with what was actually installed and produce the final energy performance score.
  5. Produce the BREL report. This bundles everything - design SAP, as-built SAP, photos, commissioning certificates - into the document that proves Part L compliance.
  6. Lodge the EPC. The final EPC is registered on the Energy Performance of Buildings Register.

OCDEA vs DEA - why it matters

Both qualifications are about producing energy assessments, but they're used in different situations:

  • DEA - existing dwellings only. Produces EPCs at sale, letting, or post-renovation.
  • OCDEA - new-build dwellings. Additional qualification on top of the DEA base. Runs design and as-built SAP, produces BREL.

If you're doing a new-build plot and you're paired with a DEA rather than an OCDEA, something's wrong. A DEA can't sign off Part L on a new home - they don't have the qualification to do so. Check the accreditation before starting.

What OCDEAs need from builders

The OCDEA's job gets much easier - and therefore cheaper, and faster - when the evidence arriving from site is clean. They need:

  • Organised photos, plot by plot. Not a zip with 300 un-named JPEGs across five plots.
  • Photos by Appendix B section. Foundations, walls, floor, roof, glazing, airtightness, heating, renewables - each with enough photos to evidence the construction.
  • GPS and timestamp on every photo. Without metadata the OCDEA can't verify when and where the photo was taken.
  • Commissioning certificates for heating, ventilation, and any renewables.
  • Any change notices. If you changed the boiler model or the insulation product, the OCDEA needs to know so the as-built SAP is correct.

Buildsnpper Assessor is the free portal for OCDEAs. Receive section-by-section photo evidence from your builder clients, review at a glance, add your branding, manage projects in one place. Always free. See how it works.

How OCDEAs get accredited

Same accreditation bodies as DEAs - Elmhurst Energy, Stroma Certification, Sava, Quidos, ECMK - with an additional on-construction qualification layered on top. OCDEAs have to maintain CPD (continuing professional development) and keep current with SAP methodology updates. The methodology changes every few years as Part L tightens, most recently driven by the Future Homes Standard.

Public registers are maintained by each scheme, so you can verify that an OCDEA you're working with is currently accredited for on-construction work.

Frequently asked questions

What does OCDEA stand for?

OCDEA stands for On Construction Domestic Energy Assessor. They are UK-accredited assessors qualified to carry out SAP assessments and produce BREL reports for new-build dwellings.

What's the difference between OCDEA and DEA?

A DEA works on existing dwellings and produces EPCs using RdSAP. An OCDEA works on new-build dwellings, runs full SAP, reviews Appendix B photographic evidence, and produces the BREL report for Part L sign-off. Every OCDEA is also a DEA; not every DEA is an OCDEA.

Do I need an OCDEA for a new build?

Yes. To sign off Part L compliance on a new dwelling in England or Wales, you need an accredited OCDEA. A plain DEA doesn't have the required on-construction qualification.

How do I find an OCDEA?

Check the public registers maintained by the UK accreditation bodies - Elmhurst Energy, Stroma, Sava, Quidos, or ECMK. Each register lets you filter by OCDEA status and by location.

How much does an OCDEA cost for a new build?

Fees vary by project size and scope, but a typical new-build SAP and BREL package ranges from a few hundred pounds for a single plot up to several thousand for a larger development. The cleanliness of your Appendix B evidence affects the final cost - messy photos mean more assessor time.

Can an OCDEA issue the EPC?

Yes. Once the as-built SAP is complete, the OCDEA lodges the EPC on the Energy Performance of Buildings Register as part of the handover process.

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