SAP Calculations

What is SAP and what are SAP Calculations? Best Updated Guide 2021

SAP Calculations

SAP Calculations are commonly used by the government and are an essential part of building compliance. This article covers what they are, when and why they are used, and why it is useful to understand them.

What Does SAP Stand for in Building?

SAP stands for sap stands for Standard Assessment Procedure and is a government-approved process for conducting an energy assessment on residential properties. These calculations are not required for commercial or other business premises, only dwelling premises. SAP calculations are needed prior to the commencement of work on buildings.

What Does an SAP Calculation Measure?

SAP Calculation Measure

Commonly used in the UK, the government require that a SAP calculation is carried out by SAP assessors, in order to award properties with either a new or updated energy performance certificate. This certificate is known as an energy performance certificate epc. The calculations come in format L1A, for new buildings, and L1B for extensions and conversions, or part l1b of the building.

The SAP Calculation varies slightly between England and the rest of the UK.

In Scotland and Wales, the Calculations determine a Dwelling Emission Rate for the property, which must comply with building regulation standards by being lower than the Target Emissions Rate (TER). Building regulation standards set by building control are tighter in Scotland and Wales than in England.

In England, the slightly varied SAP calculation also measures the properties Dwelling Fabric Energy Efficiency Rate (DFEE), which building regulations require to be the same as or higher than the Target Fabric Energy Efficiency Rate (TFEE), in addition to the Dwelling Emission Rate being the same as, or lower than, the Target Emission Rate.

How SAP Calculations Are Indicated

A SAP calculation showcases a score between 1 to 100+ for the annual energy cost. This is based on:

  • Heating System
  • Ventilation
  • Internal Lighting
  • Renewable Technologies used in the household

The higher the score is the lower running costs, 100 representing zero energy cost is very ideal. SAP calculations are also determined by location and how people use their homes. They also assist in comparing how energy running costs differ across dwellings in the UK.

Clients or designers submit drawings, plans and specifications to the assessor. The SAP calculations need to be determined in the early stages of the design process as this will prevent over budgeting and redesigning of the dwelling.

SAP calculation reports usually take between 5-10 working days after the request is made. This also depends on the timeline the project and construction detail.

It is very important that the information given to the assessor is accurate as the calculations are done on a desktop and not on as a site survey.

The Environment

The first to benefit from low carbon emissions and low CO2 emissions, is the environment. Less fossil fuels are used overall as the heating systems in the homes are being used to the maximum effect.

When the plans and drawings are provided by the designer, the assessor also prepares a summary of numbers which include the total floor area in most of the rooms, as well as areas of the heat losses on the floors, walls and roofs.

Financial Benefits

Having a more energy efficient home leads to financial benefits for the householders. An energy efficient home can also lower your heating bills by a large percentage. Your house will also be more comfortable in terms of the thermal elements. This includes a combination of humidity, temperature, air movement.

Another benefit is the Return On Investment (ROI). A home that is energy efficient immediately generates returns on the investment made by the owner. The energy that a building saves is of good value and means that the home will create an instant cash flow from the onset.

Depending on an owners’ lifestyle, a home that is well taken care of and that is energy efficient will have a high chance of a good resale.


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