SAP Calculations

What is SAP?

SAP stands for Standard Assessment Procedure. This is the only officially approved government system for assessing the energy rating for a new home. Assessors who carry out the calculations must all be accredited and registered with a certification body.

SAP Calculations are a requirement of the Building Regulations and are required for all newly built dwellings in the UK. All new homes are required to have a SAP calculation under Part L of the Building Regulations since 1995. As a result, most developers will be familiar with it.

However, for many first time developers, it will be a new and often challenging aspect of the planning and building control process.

Conversions and extensions of dwellings may also require a calculation – but slightly different rules apply.

The SAP Calculations establish an energy cost based on the construction of the home, its heating system, internal lighting and any renewable technologies installed. It does not include the energy used for cooking or appliances.

A SAP calculation indicates a score from 1 to 100+ for the annual energy cost based on:

  • The elements of structure
  • The heating and hot water system
  • The internal lighting
  • The renewable technologies used in the home

The higher the score the lower the running costs, with 100 representing zero energy cost. Dwellings with a rating in excess of 100 are net exporters of energy.

Why do I need SAP?

To meet current UK building regulations, home builders will need to gain a ‘pass’ on their SAP Calculation. Dwellings cannot be signed-off and the property cannot be let or marketed for sale without a specific calculation.

There are other reasons to care about SAP. A SAP assessor can help the designer or architect to shape the energy profile of a new dwelling – minimising its energy use and carbon emissions.

Different construction types, heating systems and technologies can be accurately measured and in turn delivered on the ground.

Another key point is that the SAP rating broadcasts the energy performance of the property, and in turn informs the Energy Performance Certificate (EPC) which all buyers and tenants see.

A ‘Pass’ is gained by meeting several compliance targets around:

  • How well the fabric of the dwelling contains heat
  • Solar gain
  • Quality of construction and commissioning of systems
  • Predicted CO2 emissions from the dwelling

Within the UK the cost of energy for dwellings can be compared to having a SAP calculation.

To achieve this the calculations are predominantly location independent and are based upon a notional standard occupancy that overcomes variations associated with a physical location and the differing ways in which people utilise their homes.

A SAP calculation for a new dwelling is a desktop exercise, the client or their designer submits drawings, plans and specifications of the development to the assessor.

Producing the calculation early in the design process will help prevent any costly re-design of the dwelling.

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