Understanding Energy Assessments in New Build Projects

When planning a construction or renovation project, understanding energy performance is crucial. How does an Energy Assessor go from receiving your building plans to producing Part L Compliance reports? There are generally two methods, both use an approved software tool called SAP or SBEM (Hence our name Sap2Sbem if you were wondering!)

In this article, we will explore the essentials of SAP energy modelling, its benefits, and how it differs to SBEM modelling yet both integrate with other assessments such as Excessive Glazing Calculations, Energy Reports or Climate Change and Sustainability Statements..

What is a SAP Energy Assessment?

SAP (Standard Assessment Procedure) energy modelling plays a vital role in assessing and pre-determining how energy-efficient a residential or domestic new building will be. This assessment process helps architects, builders, and homeowners make informed decisions at the planning stage to reduce energy consumption and comply with the Part L (ADL1) of the Building Regulations. This differs from an rdSAP Assessment, which is designed primarily for existing buildings and the type of survey you would require when renting or selling a dwelling.

SAP stands for Standard Assessment Procedure. It is the UK government's method for calculating the Buildings Energy Performance. New Build SAP Energy Assessments evaluates how much energy a building will use for heating, hot water, ventilation, and lighting. The results help determine the building's energy efficiency rating, which is essential for meeting building regulations and obtaining a good EPC score.

A New Build SAP considers various factors such as insulation levels, heating systems, window types, and renewable energy sources. By inputting these details into a specialized software, the model predicts energy consumption and carbon emissions, scoring these into separate measures for the Buildings Fabric and the Buildings CO2 emissions. The information produced in this design stage model guides decisions on improving building design to achieve better energy performance and ultimately, in the case of a new build SAP calculation, a Part L pass.

For example, if a project includes installing double-glazed windows and solar PV panels, a SAP assessment gives the Assessor an opportunity to improve on these features (e.g. the proposed U Value of the glazing can be reduced or the PV array increased) to reduce energy use and costs. This then makes it easier to justify investments in energy-saving technologies, and simply demonstrates one method of how we can make adjustments to a failing SAP assessment to achieve a Part L pass.

New Build residential building with solar panels recommended in a SAP calculation

How a SAP Assessment Benefits Your Project

Having a SAP Assessment carried out offers several practical advantages:

• Compliance with Regulations: Building regulations in the UK require energy performance assessments. SAP modelling is the approved Part L method that ensures your project meets these standards. doing this at the design stage (pre construction) can mean avoiding costly delays or redesigns.

• Cost Savings: By identifying energy-efficient options early and in the right places (eg the building's fabric- walls, floor roof, etc.) you can reduce long-term energy bills for the property. The SAP model coupled with the assessors experience can help prioritize improvements that offer the best return on investment.

• Environmental Impact: Lower energy consumption means reduced carbon emissions. As one of the measures is the buildings CO2 emissions, a SAP Assessment supports the governments targets for sustainable building practices and helps achieve greener building stock in the UK.

• Design Optimization: The SAP model highlights areas where insulation or heating systems can be improved. This leads to better comfort for the future occupier (whether temperatures go up or down over the long-term!) and reduced energy waste. An area where vast improvements have been seen in SAP methodology recently has been the recording of the Thermal Bridge Values (PSI Values). The targets have been harder to reach and virtually eliminated 'default' values from being allowed to be used in new build SAP Calculations (read my blogpost here if you want to expand your knowledge on that topic)

• Market Value: Energy-efficient buildings are more attractive to buyers and tenants. A good SAP rating can increase property value and marketability.

  
  

For instance, a developer planning a new housing estate can use a SAP assessment to compare different heating systems. The model might reveal that a heat pump system, although more expensive upfront, results in lower energy costs and emissions over time and may mean other renewable technology is not required (such as PV arrays). When assessing developments, is common at SAP2SBEM that we will offer a few main heating scenarios for our clients to give them two or three viable compliance options to consider.

What is an SBEM Assessment and are they used in residential settings?

SBEM stands for Simplified Building Energy Model. It is an approved assessment tool used primarily for non-domestic buildings such as offices, shops, and schools. While SAP focuses on residential properties, SBEM assesses the energy performance of commercial and public buildings and therefore wouldn't usually be used in a residential setting. The only caveat is when a property is effectively deemed a business and has residential areas, such as a House of Multiple Occupation (HMO's), boarding houses, pubs with residential accommodation and the like. If you are unsure and you have a project, I would be happy to review it for you and advise, or, alternatively you could get in touch with your local Building Control or Planning department who would be able to confirm the type of survey they would require.

SBEM calculates energy use based on building geometry, construction materials, and installed systems. An SBEM assessment can produce an Energy Performance Certificate (EPC), and can also be used demonstrate compliance with Part L of the building regulations through issuing a BRUKL Certificate.

Understanding the relationship between SAP and SBEM is important for projects that include both residential and non-residential elements. For example, a mixed-use development with apartments and retail spaces will require both assessments.

Commercial building with glass facade and flats above, requiring both SAP and SBEM Calculations

If you need expert assistance with these assessments, sap2sbem provide professional support to ensure accurate and timely Part L compliance.

The Key Steps in Conducting SAP Assessments

To carry out SAP energy modelling effectively, these are the essential steps followed:

1. Client sends us the Building Information: The SAP Assessment is desk based. There is no need for us to visit the property, provided the details can be supplied. This will include collected detailed data on the building’s dimensions, materials, heating systems, ventilation, and lighting. These are usually presented in the professional format of either scaled PDF plans or AutoCAD drawings and building specification lists.

2. We then Analyse, and Input Data into SAP or SBEM Software: Depending on the project type as listed above, we will calculate the project to approved methodology and then use either approved SAP or SBEM software to enter the collected information. This software is designed to follow the latest government standards as set out in ADL1 or ADL2

3. Run the Simulation: The software calculates energy consumption, carbon emissions, and energy efficiency ratings and any errors at this stage are addressed.

4. Analyse Results: We review the output to carefully identify areas for improvement. This can take quite a bit of time as we try many different scenarios for compliance. As we have background in construction we often will understand which routes will be more cost effective and try to favour these whenever possible.

5. Implement Recommendations: Adjust the building design or systems based on the model’s suggestions to enhance energy performance. We then will feed these potential changes to the client to see if these are still within the budget and project scope.

6. Generate Reports: Once payment has been received we will produce and release the official documentation such as Energy Performance Certificates (EPCs) or compliance certificates required by building authorities. Quite often, along with these we will also provide Energy Statements, Climate Change and Sustainability Statements, Part G Water Efficiency Calculations, Part O Excessive Glazing Calculations and U Value calculations.

   
   

For example, if after assessing the design the model shows excessive heat loss through walls, substituting wall insulations, or upgrading wall materials can be a small tweak that can take a wall U Value from figures like 0.2W/m2.k to 0.14W/m2.K. This iterative process applied to each areas helps optimize the building before construction begins.

Quick Wins to Achieve Part L Compliance for a SAP Calculations on an Existing Building

Improving your building’s SAP rating can be straightforward with the right strategies. Here are some actionable recommendations:

• Upgrade Insulation: Use high-quality insulation in walls, roofs, and floors to reduce heat loss. For example, the simple step of rolling out insulation in the loft area can reduce the U Value there to 0.11W/m2.K. Another option could be to add cavity bead insulation to existing cavities.. quick wins if a target value needs hitting and space is tight.

• Install Efficient Heating Systems: Consider modern boilers, heat pumps, or underfloor heating for better energy use, especially if the property is having a make over anyway.

• Use Double or Triple Glazing: Windows with multiple panes reduce heat transfer and improve comfort. These improvements can make a big difference for a SAP Calculation on existing buildings.

• Incorporate Renewable Energy: Solar panels, wind turbines, or biomass boilers can significantly lower carbon emissions.

• Improve Ventilation: Mechanical ventilation with heat recovery (MVHR) systems maintain air quality while conserving energy. These can be expensive to retrofit however, therefore If the sealing around windows, pipes etc. has been carried out well, it may be worth having an Air permeability Test carried out and entering the test score into the SAP calculation. This can improve the SAP rating and the subsequent EPC.

• Optimize Lighting: Use LED lighting and smart controls to reduce electricity consumption. These are cheaper now to buy and have quick paybacks.

  
  

By applying these measures, you can achieve a higher SAP rating, which benefits both the environment and your budget. Critically, these can improve your EPC rating if the existing building has undergone a conversion or change of use status.

Insulation material installation in timber frame cavity wall, reducing the U Value

Moving Forward with New Build Energy Assessments in Your Next Project

Energy Assessments are an essential tool for anyone involved in building design or renovation. They provide clear insights into energy use and helps meet regulatory requirements here in the UK for new Build projects, extensions and conversions or change of use projects. By understanding the process and benefits, you, along with the input from your SAP Assessor can make smarter choices that save money and reduce environmental impact.

Whether you are a homeowner, architect, or budding property developer, integrating SAP assessments and SBEM assessments early in your project planning will lead to better outcomes.

For professional guidance and reliable energy modelling services, consider reaching out to the team of experts in Energy Assessment at sap2sbem, led by Justin Barker. Their experience can streamline the process and help you achieve your goal of an energy efficient project, Part L Compliance and a budget friendly route.

By prioritizing energy assessment and by picking the right team of assessors to work along with you, your projects will be more sustainable, cost-effective, and future-proof (and less of a headache!)

Reach out to us today either with your next project or if you want to simply run something by me related to this article.

Justin Barker