How to Prepare for SAP Calculations

How to Prepare for SAP Calculations: What You Need to Provide

When you’re building a new home or converting a property, one essential step is obtaining SAP Calculations. These calculations determine whether your project meets UK Building Regulations Part L and help generate your Energy Performance Certificate (EPC).

But to get an accurate and efficient SAP report, preparation is key. Knowing what information to provide can save you time, money, and hassle down the line.

In this guide, we’ll cover exactly what you need to supply to your SAP assessor—so you can move your project forward smoothly.

✅ What Are SAP Calculations?

SAP stands for Standard Assessment Procedure. It’s the UK government’s approved method for assessing the energy performance of residential buildings.

SAP Calculations are required for:

New build homes
Conversions (e.g. barn-to-home)
Extensions with high glazing
Certain refurbishments

👉 Related Reading: When Do You Need SAP Calculations

🧾 What to Provide for SAP Calculations

To begin your SAP assessment, your assessor will need a set of drawings, technical details, and specifications. Here’s a full breakdown:

🏗️ 1. Detailed Floor Plans

These should include:

All floor layouts
Room names and dimensions
Gross internal floor areas
Floor-to-ceiling heights

📌 Tip: Plans should be to scale and in PDF or DWG format.

🧱 2. Section and Elevation Drawings

These help your assessor calculate heat loss through different parts of the building.

Please include:

Cross-sections showing floor levels and roof structure
Front, side, and rear elevations
Window and door positions

🔲 3. Construction Specification (U-values)

For each element of the building envelope, provide:

Wall types and insulation levels
Roof build-ups and insulation
Floor construction
Thermal bridging details

If you’re unsure of U-values, your assessor can calculate them—just ensure you describe the layers and materials used.

👉 Also see: EPCs for Residential Properties

🪟 4. Window and Door Details

For all windows and doors, provide:

Sizes and locations
Frame materials (uPVC, timber, aluminium, etc.)
Glazing types (double/triple glazed, low-E coating)
Overall U-values or manufacturer specs

⚠️ Note: Windows have a major impact on SAP scores—especially in glazed extensions.

🔥 5. Heating and Hot Water Systems

Include:

Boiler type and efficiency (if applicable)
Heat pump model and SCOP
Underfloor heating or radiators
Hot water cylinder size and insulation
Controls (thermostats, timers, zoning)

If using renewables, include them too.

💨 6. Ventilation Details

Specify your ventilation strategy:

Natural ventilation with trickle vents
Mechanical extract ventilation (MEV)
Mechanical ventilation with heat recovery (MVHR)

Also include:

Flow rates
SAP Appendix Q or PCDB data if available

🧱 7. Airtightness Testing (Optional but Recommended)

Let your assessor know:

Whether you plan to do an air tightness test
Or whether to use the default air leakage rate

A good airtightness score can significantly improve your SAP rating and EPC.

⚡ 8. Renewable Technologies (If Applicable)

If you’re installing renewables, provide:

Solar PV size in kWp
Solar thermal system info
Battery storage details
Heat pump or hybrid system documentation

📂 9. Any Additional Notes or Documents

This might include:

Planning conditions
Part L compliance notes
Architect or developer briefs
Building Control requests

🛠️ What Happens If You Don’t Have All the Info?

Don’t worry—at Assessment Hive, we work flexibly.

If you’re still finalising your design, we can:

Use standard assumptions based on SAP conventions
Offer advice to help you meet compliance
Update your SAP report when more details are available

However, providing accurate specs from the outset means faster results and fewer revisions.

🚀 Speed Up Your SAP Process: Our Top Tips

✅ Submit drawings in PDF or DWG
✅ Confirm glazing and heating specs early
✅ Communicate any design changes quickly
✅ Book your air pressure test in advance (if required)

Get SAP Calculations with Assessment Hive

At Assessment Hive, we offer fast, professional SAP Calculations across the UK. Whether you’re building from scratch or converting a property, our team is here to help you meet compliance and move your project forward.

Fast turnaround
Competitive pricing
Remote, nationwide service