Last edited 26 Jul 2019

ISBEM

[edit] Introduction

iSBEM is the free user interface that accompanies the Simplified Building Energy Model (SBEM) software developed by BRE to indicate compliance for non-domestic buildings with parts L2a and L2b of the building regulations.

[edit] Background

On 9 January 2013, the Energy Performance of Buildings (England and Wales) Regulations 2012 took effect. The regulations require that energy performance certificates (EPCs) are produced for certain dwellings and non-dwellings.

EPCs set out the energy efficiency rating of buildings. They are required when buildings are built, sold or rented, if they have a roof and walls and use energy to condition an indoor climate. If a building contains separate units (for example a block of flats), each unit needs an EPC, but they are not required for shared bedsit type accommodation.

Producing an EPC for existing buildings uses the same calculation methodology as assessing the energy performance of new buildings. To show the energy performance of buildings complied with Part L of the Building Regulations, the UK Department for Communities and Local Government commissioned the National Calculation Methodology (NCM). It describes the procedure, for buildings other than dwellings, for demonstrating compliance with the carbon emission requirements of regulation 17C of the Building Regulations; it also describes the procedure for calculating ‘operational ratings’ and ‘asset ratings’ for EPCs in relation to the Energy Performance of Buildings Directive (EPBD).

The calculations – which include target emission rates and building emission rates – can be performed using approved simulation software (approved Dynamic Simulation Models (DSMs)) or by using the Simplified Building Energy Model (SBEM), available to download from the NCM website. Unlike some of the DSM's, SBEM is a 'simplified' compliance tool, rather than a design tool and is used to determine CO2 emission rates for new non-domestic buildings in compliance with Part L. SBEM calculates the energy demands of each space in a building according to the activity that takes place.

iSBEM is a relatively simple interface for SBEM which:

Allows the user to tailor the model to the building occupier's actual operating regime by unlocking the standard parameters in the NCM Activities Database;
Enables the user to more easily explore and document the savings in energy use resulting from the installation of one or more energy efficiency measures, in one or more packages of measures;
Accepts information on fuel costs, so as to calculate the approximate value of these energy savings;
Provides a means to normalise the calculated energy use data against measured fuel consumption, adjusting for the effects of energy management practices.