If you’re building a new home in the UK, one of the first hurdles you’ll face is compliance and right at the heart of that is a three-letter acronym you’ll hear a lot: SAP.

SAP calculations (Standard Assessment Procedure) aren’t just about ticking boxes. They’re the measure of your building’s energy efficiency and the gateway to your Energy Performance Certificate (EPC). Without them you can’t sell or rent your property.

But here’s the question most people ask: what information do I actually need to provide for SAP calculations? At Gradwell Group, this is something we help clients with every single day  making the process clear simple and stress free.

Let’s break it down.

Why SAP Calculations Are So Important

Before we look at the information you’ll need it’s worth remembering why SAP exists in the first place.

• SAP proves your project meets Building Regulations Part L.
  
  
• It checks how well your home will keep in heat use energy and cut emissions.
  
  
• It generates the EPC which every new property must have.
  
  

In simple terms: no SAP means no EPC and no EPC means you can’t legally sell or let your property.

Want to know more about the process? Take a look at our SAP Calculations for New Builds page.

The Key Information Your Assessor Will Need

Here’s what we’ll ask for when preparing your SAP calculation:

1. Plans and Site Details

• Floor plans elevations and sections.
  
  
• The full site address and postcode.
  
  
• The orientation of the home (north, south, east, west).
  
  

Why it matters: The way a house faces can affect solar gain heating needs and natural light.

2. Walls Floors and Roof

• Construction details and insulation levels.
  
  
• U-values for walls floors and roofs.
  
  
• Details of thermal bridging (where heat might escape).
  
  

Fact: A wall with a U-value of 0.18 W/m²K performs far better than one at 0.35. Lower numbers mean better insulation.

3. Windows and Doors

• Window type glazing specification and frame material.
  
  
• Door construction and U-values.
  
  
• Percentage of glazing on each elevation.
  
  

Even small changes triple glazing instead of double can make a noticeable difference in SAP scores.

4. Heating and Hot Water Systems

• The type of heating system (gas boiler, heat pump, electric).
  
  
• Efficiency ratings of boilers heat pumps or stoves.
  
  
• Hot water cylinder details including insulation thickness.
  
  
• Controls: thermostats TRVs programmers.
  
  

5. Ventilation and Air Tightness

• Natural ventilation, mechanical extract or MVHR system details.
  
  
• Air permeability test results (or a target value at design stage).
  
  

Poor airtightness can account for 25% of total heat loss in homes making this one of the most critical data points.

6. Renewables

If you’re planning green tech your assessor will need details on:

• Solar PV systems (capacity, orientation).
  
  
• Solar thermal water heating.
  
  
• Heat pumps air ground or hybrid.
  
  
• Biomass boilers.
  
  

Renewables not only improve your SAP rating but also boost your property’s market appeal.

7. Lighting and Other Features

• The percentage of low energy light fittings.
  
  
• Any advanced energysaving technologies included.
  
  

A simple switch to LEDs can improve your overall SAP score and cut bills at the same time.

Why Accuracy Matters

It might feel like a lot of information but every detail makes a difference. Inaccurate or missing data can lead to:

• Delays in gaining building control approval.
  
  
• Failed SAP assessments requiring redesign.
  
  
• Unexpected costs to retrofit energy-saving measures.
  
  

By providing the right information early you’ll save time money and stress. That’s why we always recommend booking a design-stage SAP assessment before construction begins.

The Gradwell Group Difference

Here’s how we make SAP simple:

• Fast turnaround standard reports within 48 hours same day available.
  
  
• Affordable pricing new build SAP calculations from just £70 + VAT.
  
  
• Expert advice we don’t just report we guide you on improvements.
  
  
• Nationwide coverage trusted by homeowners developers and architects across the UK.
  
  

Take a look at our full SAP Calculation Services to see how we can support your project.

Quick Recap

• SAP calculations check energy performance and compliance with Part L.
  
  
• You’ll need to provide plans, insulation details, heating and ventilation info.
  
  
• Renewables, lighting and airtightness all impact your final score.
  
  
• Accurate details mean smoother approvals and better energy ratings.
  
  
• Gradwell Group provides expert, affordable SAP services across the UK.

Looking Ahead

The government’s Future Homes Standard 2025 will demand a 75–80% cut in carbon emissions for new builds. That means energy performance is only going to get more important. 

FAQs

Q1. What documents do I need for a SAP calculation?

 You’ll need architectural floor plans elevations and construction specifications. Details on insulation heating systems windows and doors are also required.

Q2. Do I need U-values for SAP calculations?

 Yes. U-values for walls floors roofs windows and doors are essential as they measure heat loss and play a key role in your SAP score.

Q3. Can I get a SAP calculation without final construction details?

 Yes, at the design stage. You can provide drawings and proposed specifications. The assessor can update details later when products are confirmed.

Q4. How much detail is needed on heating and hot water systems?

 You’ll need to provide the system type (boiler, heat pump, etc.) efficiency ratings controls and hot water cylinder specifications if used.

Q5. Is an air tightness test result required for SAP?

 Yes either a target figure at design stage or the final air test result after construction. Poor air tightness can reduce your SAP rating.

Final Thoughts

Getting a SAP calculation done isn’t just about compliance it’s about building homes that are efficient affordable to run and future ready.

At Gradwell Group, we make the process straightforward we collect the information you need handle the details and deliver fast accurate results that keep your project on track. Ready to get started? Contact Gradwell Group today and let’s take the stress out of SAP compliance.

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