GBC Version Development

GBC Version 1 Features


  • Whole Building and Room-by-room schedule of accommodation:
    • add: dimensions: areas and volumes calculate automatically,
    • add: hours of operation, design temperatures inside and out
  • Room-by-room heat loss calculator:
    • determine radiator or underfloor heating requirements;
    • to size the boiler or insulate to meet the boiler size.
  • Analysis of Form Factor:
    • optimal U values to respond to them,
    • thickness of different insulation materials
  • Elements and secondary-elements:
    • select from ready-made lists to match the project;
    • dimensions are added by the user and their areas are automatically calculated
  • Schedules of windows, rooflights and doors:
    • Since they may come in a multitude of sizes
  • Building Performance Targets:
    • Users can compare and choose between:
    • Building Regulations Part L,
      • other national standards
    • Design Standards:
      • LETI, AECB CarbonLite, Passivhaus, EnerPHit,
      • Environmental Assessment Methods: BREEAM etc.
      • other national design standards,
    • including: U values, Airtightness, Form factors, Elevation glazing percentage and orientation
  • Automatically and instantly see what thickness of different k-value insulation materials is needed to meet targeted U values
  • Elemental Assemblies:
    • Allows user to choose a combination of functional components and then choose the materials or products for each component
  • Costs of insulation, windows and energy savings:
    • Helps users to persuade clients to spend money on insulation and higher performance windows and glazing (Version 1 only)
  • Bill of materials, quantities, labour and costs:
    • enables cost planning and proper value engineering (Version 2)
    • based on building fabric only (Version 2) services  in later versions
  • Element Summary: compare calculated U values with selected or target U values. highlighting ‘pass’ of ‘fail’
  • Summary of calculated energy losses or demands:
    • For each element, secondary-element and whole building
    • Totals elements and secondary elements as a percentage of the whole
  • Allows comparisons to be made, by the user, to prompt reconsideration of earlier decisions

GBC Versions 2 Features: under development


Green Building Calculator V2 is being developed now, including:

  • Bill of Materials, Quantities, Accessories, Products, Labour, Costs,
    • For Cost Planning, Quote collection, Tendering
  •  Retrofit:
    • Historic fabric element upgrades, inside or out
    • Add domestic furniture fixtures & equipment
    • Add solar shading, decking, pergolas,
    • Add hard and soft landscape
  • Embodied Energy, Embodied Carbon, Sequestered Carbon Calculator (EE EC SC)
    • ICE Database v1.6 > v3 (for EE EC)
  • Domestic Landscape Elements
  • Basic Civils & Infrastructure Elements
  • More Generic Material datasets

GBC Versions 1 to 35 Summary


The development order is subject to GBC user feedback:

35 Versions are now planned to add to their functionality in the following years including:

  • V1 Building dimensions, form factor, regulations, design standards, temperatures, hours, elemental assemblies, in-use energy, fuel choice, carbon in-use
  • V2 Retrofit, Terraces, Community level, MEP Services
  • V3 Decrement Delay, Form Factor refinements: dormers, bays, porches
  • V4 Building Section Coding, Competent Application,
    • 892 ready made elements, Bespoke Assemblies, Accessories, Specification Generator
  • V5 Non-Domestic, Retrofit and Newbuild more refinement
  • V6 Embodied Energy, Carbon and Sequestered carbon; Non-external envelope elements
  • V7 Condensation Check, Thermal Bridge, Secondary Element Calculator, Thermal mass calculator
  • V8 LCA Calculator
  • V9 Landscape
  • V10 Civils and Infrastructure: scope Increased
  • V11 Waste Calculator using WasteCost®Lite
  • V12 Plastic free v Recycled Plastic
  • V13 Interiors: Scope increased, Ska fit-out. refit
  • V14 Circular economy: Reclaim Reuse
  • V15 Self-build Interface
  • V16 CAD BIM App
  • V17 Whole Project Budget Calculations, full Fee bid calculation based on cost plan
  • V18 EU and International versions
  • V19 Services Design Module: Occupancy level, Energy Sources and uses,
  • V20 Lighting Design Module: Health & Wellbeing, Light Nutrition
  • V21 Biodiversity Inclusion, Biodiversity Net Gain
  • V22 Local Climate Appropriate construction and materials
  • V23 Vernacular, local: materials, trades, economy
  • V24 GBPB Green Building Price Book
  • V25 O&MM Operation & Maintenance Manuals
  • V26 FM Specification
  • V27 Local Procurement, Transport to site, distance search facility
  • V28 On Site Construction Emissions
  • V29 Design Life, Durability and Competent Products
  • V30 Air tightness & Energy Loss
  • V31 Value Engineering Opportunities: in not out
  • V32 Healthy Building
  • V33 Screening Priorities
  • V34 Indoor Air Quality
  • V35 Natural Lighting Levels

B Bespoke

Discussions have started or bespoke versions are being developed

  • B1 Retrofit Window & Insulation Calculator
  • B2 Responsible Retrofit Carbon Calculator
  • B3 Window Calculator
  • B4 Screeds Calculator
  • B5 QS interface

Future Development


  • GBC will maintain a stakeholder group to ensure we make what you want and need
  • Having a large number of users will help with:
    • error detection, feedback loops, encouraged by free upgrade versions
    • developing GBC Green Building Calculator with more features and stronger datasets
  • We will encourage customisation requests to be shared; ideas will be considered for development into the core file for the greater good
  • Users will be invited to review the 35 version’s order of development, in case users want something sooner, by popular demand

GBC Version Development C#534 End.

© GBE GBC GBL NGS ASWS Brian Murphy aka BrianSpecMan **
4th September 2021 – 19th October 2021