Design Energy Calculations
SAPs, EPCs
& Design Water Use Calculations

Standard Assessment Procedure (SAP) calculations are a mandatory requirement for any new build dwelling. SAP is used to show compliance with Part L of the Building Regulations and is applied at the design stage of the build process.

SAP calculates the energy cost and carbon emissions generated to heat, light, ventilate and provide hot water to a building.

SJI designs Ltd can produce energy design calculations for

  • New Build Dwellings
  • Conversions
  • Extensions (where the amount of glazing is deemed high)


We provide advice and guidance on how to make your project comply in the most effective manner.

Existing Dwellings.

Part L1B of the Building Regulations covers works on existing dwellings.

In some instances, a SAP calculation may be required to assess an existing dwelling.

For Example, an extension with large glazed areas, which forms part of the main dwelling, may not appear to comply with current legislation. However, if the whole dwelling is considered by use of a SAP calculation, it may be possible to show that compliance can be achieved.

If you would like any of the above services, please contact us for a fee quote.

Fees are dependant on the type of project such as multiple dwellings, size and type.

Full construction details are required to enable a SAP calculation to be undertaken.

For further details of what information is required, please contact us

Pressure Testing.

Pressure Testing is a simple and effective way to maximise your EPC (Energy Performance Certificate) rating and ensures you achieve a high quality build.

Upon completion of a new build project,  some dwellings require a Pressure Test to prove compliance with Part L1 of the Building Regulations. Pressure Tests identify air leakage paths using special equipment and is undertaken on site once the build has been constructed.


Pressure Tests quite often uncover air leakage paths via skirting boards, loft hatches and bath panels. 

Eliminating air leakage paths can help a developer to determine whether the dwelling has been built to a high standard and also improves the overall energy efficiency – hence, a higher rating on the EPC for the dwelling and therefore, enhanced saleability.

SJI designs Ltd  can arrange for a pressure test to be carried out should the design calculation / building design require one when showing compliance with the building regulations.

Standard Assessment Procedure (SAP) calculations are a mandatory requirement for any new build dwelling. SAP is used to show compliance with Part L of the Building Regulations and is applied at the design stage of the build process.

SAP calculates the energy cost and carbon emissions generated to heat, light, ventilate and provide hot water to a building.

SJI designs Ltd can produce energy design calculations for

  • New Build Dwellings
  • Conversions
  • Extensions (where the amount of glazing is deemed high)


We provide advice and guidance on how to make your project comply in the most effective manner.

Existing Dwellings.

Part L1B of the Building Regulations covers works on existing dwellings.

In some instances, a SAP calculation may be required to assess an existing dwelling.

For Example, an extension with large glazed areas, which forms part of the main dwelling, may not appear to comply with current legislation. However, if the whole dwelling is considered by use of a SAP calculation, it may be possible to show that compliance can be achieved.

If you would like any of the above services, please contact us for a fee quote.

Fees are dependant on the type of project such as multiple dwellings, size and type.

Full construction details are required to enable a SAP calculation to be undertaken.

For further details of what information is required, please contact us

Pressure Testing.

Pressure Testing is a simple and effective way to maximise your EPC (Energy Performance Certificate) rating and ensures you achieve a high quality build.

Upon completion of a new build project,  some dwellings require a Pressure Test to prove compliance with Part L1 of the Building Regulations. Pressure Tests identify air leakage paths using special equipment and is undertaken on site once the build has been constructed.


Pressure Tests quite often uncover air leakage paths via skirting boards, loft hatches and bath panels. 

Eliminating air leakage paths can help a developer to determine whether the dwelling has been built to a high standard and also improves the overall energy efficiency – hence, a higher rating on the EPC for the dwelling and therefore, enhanced saleability.

SJI designs Ltd  can arrange for a pressure test to be carried out should the design calculation / building design require one when showing compliance with the building regulations.

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