New Builds

The Requirements

Building Regulations Part L1A specify the energy efficiency standards that a new build in England and Wales must achieve. There are slightly different standards applicable to Scotland and Northern Ireland.

The regulations lay down minimum standards of thermal efficiency for Thermal Elements (exterior walls, roofs, and floors), Controlled Fittings (windows, doors and roof lights) and Controlled Services (heating, lighting, ventilation and renewable energy generation). Part L1A also addresses the use of accredited constructional details to minimise non linear heat losses (e.g. cold bridges), air tightness to prevent heat loss from draughts, and summer overheating.

Overall energy efficiency is measured in terms of the annual amount of carbon dioxide (CO2) emitted as a result of the generation of energy to heat and light the property under conditions of standard occupancy. This is sometimes referred to as the carbon footprint of the property, although strictly speaking the carbon footprint includes the CO2 emissions arising from the manufacture and transport of the materials from which the property is constructed, as well as from the actual construction process.

What ESIW Provides

The local authority Building Control Officer will require documentary evidence that :

  1. A proposed new development is expected to meet the applicable standards.
  2. The completed development actually meets the applicable standards.

These requirements are met by modelling the proposed dwelling within a computer model which follows the government standard known as the Standard Assessment Procedure or SAP. The predictions of the computer model, often referred to as SAP calculations, allow the thermal efficiencies of individual Thermal Elements, Controlled Fittings and Controlled Services to be designed in order to meet the overall energy efficiency target.

Energy Services Isle of Wight is an accredited On Construction Domestic Energy Assessor (OCDEA) and as such is qualified to generate the necessary reports from the SAP model to Building Control. These include :

  1. Predicted Energy Assessment (PEA), showing the anticipated Energy Efficiency Rating (EER) and Environmental Impact Rating (EIR) for the proposed development.
  2. Energy Performance Certificate (EPC) showing the actual Energy Efficiency Rating (EER) and Environmental Impact Rating (EIR) for the completed development.
  3. Part L1A checklist showing that all individual requirements of Building Regulations Part L1A will be / have been met.

 

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