Could the wrong energy assessment leave your property project with the wrong paperwork or key information missing? The term can refer to several different services. An EPC for an existing property is not interchangeable with calculations or testing for a building project. It’s understandable to be unsure where to start, especially when the right service depends on what you’re doing.
This checklist will help you identify the assessment or calculation that fits your situation, gather information an assessor may need and agree practical next steps before booking. It distinguishes domestic and commercial EPCs from SAP, overheating, heat loss and water calculations, as well as airtightness testing. You’ll also find prompts for checking project requirements, arranging site access and asking the right questions, so you can describe what you need and avoid commissioning a service that doesn’t fit.
Key Takeaways
- Start with the property decision or project requirement to narrow down the right energy assessment.
- EPCs, SAP calculations, heat loss calculations, overheating calculations, airtightness testing and water calculations serve different purposes.
- Before booking, ask what the assessment will provide and what information or site access the assessor needs.
- Compare providers by relevant experience, scope and communication, then agree a suitable next step.
Energy assessment explained: identify the right starting point
An energy assessment is an evaluation, calculation or test selected to answer a particular question about a property or building project. The right service depends on the building, the stage of the project and what you need to establish. An EPC, for example, is a certificate describing a property’s energy performance. It is not interchangeable with project calculations or testing. You can read more about the Energy Performance Certificate and its role in communicating a property’s energy performance.
Each service has a distinct purpose. SAP calculations assess a dwelling’s energy performance as part of a new-build project. Heat loss calculations estimate heat escaping from a building to inform heating design, while overheating calculations assess the risk of excessive internal temperatures. Airtightness testing measures how much air leaks through the building envelope. Water calculations assess expected water use for a project.
Which energy assessment fits a property or building project?
If you need an energy certificate for an existing home or commercial property, ask about a domestic or commercial EPC assessment. If you’re planning a new dwelling or progressing building work, the requirement may instead call for SAP or another project calculation or test. The SAP calculations guide explains this service in more detail.
Before arranging an assessment, describe the decision or requirement you’re trying to address. For example, say whether you need a certificate for a property or evidence for a building project, and explain the project stage. This gives the assessor a clearer basis for confirming which service is relevant and what information may be needed. Assessments and calculations provide evidence or results; they do not carry out improvement work. For example, an assessment does not install insulation or solar panels.
Energy assessment checklist: what to confirm before you book
First, be clear about the decision the assessment needs to support. Are you seeking a property certificate, checking a project requirement or gathering information to guide building design? Tell the assessor the property type and project stage, then confirm the exact service, scope and expected output. If you need an EPC for a home, check the UK government guidance for homeowners for information on domestic certificates.
What information should you gather for an assessor?
Start with the property address, its use and a short description of the work or question. Gather any plans, specifications, construction details and information about the heating or other systems that you have. The useful evidence varies by service, so treat this as a starting point rather than a universal document list.
For heat loss work, details about the building fabric and heating system may be relevant. Read the guide to heat loss calculations, then ask the assessor which information applies to your property.
- Access: Confirm which rooms or areas need to be accessible and who will provide entry.
- Timing: Explain any project milestones or deadlines, then agree a suitable assessment date.
- Scope and outputs: Check what the service includes, which documents or results you’ll receive and whether anything needs to be ready beforehand.
For airtightness testing, explain the project stage and any relevant compliance requirement early. Ask what preparation is needed and which areas must be accessible. This helps avoid assumptions about what the visit covers. If heat loss calculations are also part of your project, remember that they are a separate service with a different purpose. The linked guide can help you understand them before discussing your requirements.
Choose an energy assessment provider and agree the next step
A suitable provider should understand the service you need, explain its scope clearly and tell you what you’ll receive. Compare providers on relevant experience, deliverables and communication. Before proceeding, check that the proposed work matches your property, project stage and requirement. If the scope or output is unclear, ask for an explanation before you agree to the assessment.
Energy Smart is an independent energy consultancy established in 2013. Its services include domestic and commercial EPCs, SAP and overheating calculations, heat loss calculations, airtightness testing and water calculations. The company serves Herts, Beds, Cambs, Northants, Bucks and North London. Its local coverage includes London, Bedford, Cambridge, Northampton, Luton, Milton Keynes, St Albans, Stevenage, Aylesbury and Peterborough. Ask Energy Smart to confirm availability for your location and the service you need. For commercial properties, consult GOV.UK guidance on EPCs for commercial property if you need to check the relevant information.
Questions to ask before arranging an assessment
Before you agree to proceed, ask:
- Which assessment or calculation fits my property, project stage and requirement?
- What does the service include, and what information or access will you need?
- What documents or results will I receive, and how will they be shared?
These questions help clarify the scope, particularly when you’re comparing different services. If you need a domestic EPC, you can book an EPC assessment. For another service, discuss your project with Energy Smart and confirm whether it can cover the service and location you need. A short conversation can help establish a practical next step before you arrange the work.
Make your next property project clearer
The right energy assessment starts with the question you need answered. Decide whether you need an EPC for a property or a project-specific calculation or test. Then confirm the scope, information required and expected outputs before arranging the work.
Energy Smart provides domestic and commercial EPCs alongside building compliance calculations and testing. Its service area includes Herts, Beds, Cambs, Northants, Bucks and North London, with local coverage including London, Bedford, Cambridge, Northampton, Luton, Milton Keynes, St Albans, Stevenage, Aylesbury and Peterborough. Confirm availability for your location and requirements before proceeding.
Discuss the right energy assessment for your property or project with Energy Smart.
Frequently Asked Questions
What is an energy assessment?
An energy assessment is a broad term for an evaluation, calculation or test used to answer a question about a property or building project. The appropriate service depends on what you need to establish. An EPC reports a property’s energy performance, while SAP, heat loss and overheating calculations, airtightness testing and water calculations serve distinct purposes.
Which type of energy assessment does my property need?
Start by identifying whether the property is domestic or commercial, the project stage and the certificate or requirement you need to address. An assessor can help determine whether an EPC, calculation or test is relevant. Energy Smart serves London, Bedford, Cambridge, Northampton, Luton, Milton Keynes, St Albans, Stevenage, Aylesbury and Peterborough. Confirm availability for your location.
How should I prepare for an energy assessment?
Gather the property address, details of its use and project stage, plus any plans, specifications or relevant heating-system information you have. The documents needed depend on the service, so don’t assume every item will apply. Before the appointment, confirm which areas need to be accessible, what information the assessor requires and what outputs you can expect.
Is an energy assessment the same as an EPC?
No. An EPC is one type of energy assessment, focused on a property’s energy performance. Other services answer different questions: SAP calculations assess a dwelling’s energy performance for a project, heat loss and overheating calculations examine specific design factors, airtightness testing measures air leakage, and water calculations address expected water use. The right service depends on the property or project requirement.