What is a DEA (Domestic Energy Assessor)?

A DEA - Domestic Energy Assessor - is a UK-accredited professional who produces Energy Performance Certificates (EPCs) for existing dwellings. When a home is being sold or rented, a DEA visits the property, takes measurements, and produces the EPC using a simplified version of SAP called RdSAP.

They're the assessor most homeowners have met. They are not the same as an OCDEA, who handles new builds. The letters look similar, the qualifications don't.

What a DEA actually does

Visits the existing property
Records the fabric, heating, hot water, ventilation, lighting, and any renewables
Runs RdSAP (Reduced Data SAP) using the observed data
Lodges the resulting EPC with the relevant register
Provides recommendations for improving the property's energy efficiency

A DEA visit is usually 30-60 minutes. They're not there to sign off construction work - they're documenting what's already there.

DEA vs OCDEA - the difference that matters

This is where the letters get confusing:

DEA - existing dwellings only. Produces EPCs for sale, letting, or renovation purposes. Works from what's already on site.
OCDEA - on-construction DEA. Qualified for new-build dwellings. Runs design-stage and as-built SAP, reviews Appendix B evidence, and produces the BREL report for Part L sign-off.

Every OCDEA is also a DEA - it's an additional qualification on top of the base DEA accreditation. But not every DEA is an OCDEA. If you're a builder on a new plot, you need an OCDEA specifically, not just a DEA.

Who accredits DEAs in the UK

DEAs are accredited through approved schemes. The main ones in the UK are:

Elmhurst Energy - the largest UK accreditation body
Stroma Certification
Sava
Quidos
ECMK

Each scheme maintains a public register so you can check that a DEA's accreditation is current. EPCs are lodged on the Energy Performance of Buildings Register once produced.

When does a builder interact with a DEA?

If you're doing new-build work, usually not - you'll be dealing with an OCDEA. But a DEA might get involved if:

You're renovating or extending and the property needs a new EPC afterwards
You're doing major retrofit work and the homeowner needs a post-works EPC
You're converting a non-dwelling into a dwelling (change of use)

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Frequently asked questions

What is a DEA in UK building?

A DEA (Domestic Energy Assessor) is a UK-accredited professional who produces Energy Performance Certificates for existing dwellings using the RdSAP methodology.

What's the difference between a DEA and an OCDEA?

A DEA works on existing dwellings and produces EPCs. An OCDEA is qualified for new-build dwellings - running design-stage and as-built SAP, reviewing Appendix B photographic evidence, and producing the BREL report for Part L sign-off. Every OCDEA is also a DEA; not every DEA is an OCDEA.

Do I need a DEA for Part L compliance on a new build?

No - you need an OCDEA, not a plain DEA. OCDEAs have the additional qualification required to sign off Part L on new dwellings. Make sure your assessor is accredited for on-construction work before you start a plot.

How do I find a DEA?

Check the public registers held by the accreditation schemes - Elmhurst Energy, Stroma, Sava, Quidos, or ECMK. You can search by postcode to find accredited assessors in your area. EPCs are lodged on the Energy Performance of Buildings Register.

How much does a DEA cost?

For a residential EPC on an existing dwelling, fees typically range from £60 to £120 depending on region, property size, and turnaround speed. New-build work handled by OCDEAs is priced differently and usually agreed as part of the Part L compliance package.