An energy assessor is a government-accredited professional who evaluates the energy efficiency of buildings and produces legally required documentation. For existing homes they carry out the domestic EPC assessment; for new build homes they run the SAP calculation that demonstrates compliance with Part L of the Building Regulations. Assessors must be registered with an approved accreditation scheme - such as Elmhurst Energy, Stroma Certification or ECMK - and their certificates are lodged on the national register at the Energy Performance of Buildings Register.
What they do
- Carry out on-site domestic energy assessments and produce EPCs
- Produce SAP calculations for new dwellings under Part L
- Produce SBEM calculations for new non-domestic buildings
- Lodge EPC certificates on the national register
- Produce Part L compliance reports and as-built calculations
- Advise on fabric and services improvements to raise EPC ratings
- Assess eligibility for Green Deal and ECO energy efficiency schemes
- Produce sustainability statements for planning applications
- Advise landlords on minimum energy efficiency standards (MEES)
When you need one
An energy assessor is required whenever an EPC or SAP calculation is needed - whether for a property transaction, a new build or a planning or funding condition.
Typical costs (UK, 2025)
| Job type | Typical cost |
|---|---|
| Residential EPC | £60 - £150 |
| Commercial EPC (small) | £200 - £500 |
| SAP calculation (new dwelling) | £300 - £700 |
| SBEM calculation (commercial) | £400 - £1,000 |
| Part L compliance report | £400 - £900 |
| Hourly rate | £60 - £100 / hr |
Costs vary by property size, location and assessor. Large or complex properties and commercial buildings attract higher fees. Always confirm whether the fee includes lodgement on the national EPC register.
Qualifications to look for
Domestic energy assessors must hold a Level 3 Award in Energy Assessment (Domestic) and be registered with a government-approved accreditation scheme such as Elmhurst Energy, Stroma Certification or ECMK. Check registration at the Energy Performance of Buildings Register.
SAP calculations for new build require a qualified Low Carbon Energy Assessor with software approved by BRE. Many DEAs hold LCEA qualification as well.
How to find a reputable energy assessor
Frequently asked questions
When is an EPC required?
An EPC is required when a property is built, sold or let. It is valid for 10 years. Properties exempt from the requirement include listed buildings, places of worship, temporary buildings and some holiday accommodation.
What is a SAP calculation?
SAP stands for Standard Assessment Procedure - the government-approved method for calculating the energy performance of new dwellings. It is required under Part L of the Building Regulations for all new homes and produces the predicted energy use and carbon emissions as well as the as-built EPC.
What EPC rating do I need to rent a property?
Since April 2020 all rental properties in England and Wales must have an EPC rating of E or above. The government has proposed raising this to C for new tenancies but this has not yet come into force.