Inventory of Carbon & Energy methodology for window air space fills



This methodology represents embodied energy, and carbon dioxide (CO2) emissions associated with window air space fills. The data and calculation methodology is sourced from the Inventory of Carbon & Energy (ICE), version 2.0 life cycle dataset, produced in conjunction with the University of Bath.

The methodology

Emissions model

The methodology is based on factors which describe the quantities of energy and CO2 which are 'embodied' within the use of insulating air space fills in double glazed window units. By multiplying the number of filled windows under consideration by these factors, an estimate of the embodied energy and emissions associated with that quantity can be calculated. These factors assume unit sizes of 1.2 m by 1.2 m.

Model data

Embodied energy and CO2 emissions vary between different types of air space fill. This methodology represents 4 different types: air, argon, krypton and xenon. Each type is represented by two data values:

  • embodied energy per filled window unit (MJ/window)
  • embodied CO2 per filled window unit (kg/window)

In addition, each scenario is described by a life cycle analysis boundary, indicating the stages in the window life cycle which are represented by the energy and CO2 factors, and in most cases author notes on the sourcing of the data.

Activity data required

Embodied energy and emissions are directly proportionate to the number of filled windows under consideration, which therefore must be available in order to calculate.

Calculation and results

Embodied energy and emissions are calculated by multiplying the specified number of filled windows by the appropriate factors. Two values are calculated, representing the embodied energy and CO2 emissions attributable to the specified number of filled windows.

Related methodologies

The ICE methodology for window units is separately but does indeed incorporate the present methodology into calculations for windows containing particular specified fills.

Several other methodologies sourced from the ICE database are also available. The bulk of the ICE database represents several hundred distinct materials, emissions and energy for which can be calculated on the basis of mass or area.

In addition, there exist several methodologies which provide data and calculations specific to particular types of materials: concrete and timber (including biogenic CO2 emissions).

Details of the sources of data for the ICE database are also available.

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