Full-life Cradle-to-Grave calculation

Ben Adam Smith

Domestic heating is mostly using natural gas in this country, though that is changing, you may have heard that after 2025 gas boilers won’t be available.  The largest part of what remains after these head towards zero is the embodied CO2 of the construction.  Tim goes into more depth in a recent podcast (2020) podcast 283 with Ben Adam Smith of House Planning Help.

Input Data

  • built-in library of 200 material entries from EPDs and a further 100 from summaries of EPDs
  • data entry form, new easy-to-use form to enter your own data from additional EPDs
  • referencing, data is fully referenced with links to the EPD, source of the density and product life
  • density of product is in the database, a range can also be entered and for some products you can adjust the density
  • stored carbon for timber based products is included where it applies

Process and Usability

  • standard RICS methodology including 60 year nominal life
  • matches materials automatically,  you only need adjust the choice where necessary, you can now also see both the original material and the material it was matched with, in case there is a difference
  • remembers associations you make between phrases in the PHPP and materials
  • filter EPDs, choose whether you want to see products manufactured within your country, a region e.g. Europe, or all the EPDs.


  • fully transparent calculation
  • NEW results table coloured by value makes it easy to see where the CO2 is coming from
  • NEW up to 4 options can be graphed/compared
  • NEW simpler format and option to simplify further so only the names of the materials and results are shown
  • includes CO2 stored in timber and timber based materials, also called sequestered CO2
  • Scope Summary written below the calculation for you to keep a record of exactly what is included
  • Total CO2 graph shows operational and embodied CO2 over 60 years (or longer)
  • AECB Assessment summary that is printable
  • optional RIBA tab gives RIBA 2030 Challenge results and gives data in the format for RIBA awards applications

The latest format will graph 2, 3 or 4 options.  RIBA results are also given on a separate tab.

PHribbon calculates Embodied CO2 from Cradle to Grave, covering stages A-C (and D where information is available) and is suitable for initial estimates for the RIBA 2030 Challenge.  This therefore includes :
Stage A, A1-A3 Manufacture including A4 Transport to site and A5 Construction
Stage B, Use of the building including B4 Replacement
Stage C, Demolition and Disposal of the building
And quoted separately Stage D, Reuse, Recycling potential (outside the usual scope of the main calculation)

Results are also given by each stage for each material. The automatic colouring makes it easy to spot what material is contributing most and at what stage:

Some of our recent calculations have been published in Passivhaus+ magazine (links are valid for subscribers and to others while Passivhaus+ is offering free access)

  • Steep Wedge House (new build) – issue 31 p49
  • PYC Offices (new build) – issue 32 p23
  • Greenheart Construction (new build) – issue 33 p29
  • Ruth Butler (new build) – issue 33 p38
  • and Passivhaus+ is keen to include these for regular feature of the projects they show issue 33 p18.

Results from the tool matched (within the error margins) Mark Siddall‘s own 2-3 day calculation. The Embodied tool was in development when Mark did his calculation and he was interested in a to see what it would produce, before revealing his own results. When it gave the same answer in about half an hour he said “I’ll definitely be using it next time”.