The AECB Carbon Calculator calculates embodied and operational CO₂ from Cradle to Grave. It is a very specific version of PHribbon that only calculates Whole Life Carbon and doesnt work with a PHPP (Passive House Planning Package) energy calculation. That makes it self contained to some extent, though to include the emissions from the building in use (operational carbon) you will need results from SAP, SBEM or software other than PHPP. It’s written by the same author of PHribbon, Tim Martel who combined his experience working in research and development, VBA programmer, Certified Passivhaus Designer and Chartered Architectural Technologist. He is currently the AECB Standards and Certification Programme Manager.

This video explains the main features. Best viewed in HD, use the Youtube cog and change resolution to 1080p.

You will need results from your own energy software, e.g. SAP, SBEM (PHPP users should use PHribbon instead).

Tim Martel 2026

Input Process

• Built-in library of 1000 entries, mainly EPDs with info for [A]-[D] including sequestration for timber/natural materials, some entries also have info on the uncertainty factor (an estimate of the reliability of that data)
• UK/Ireland Reference Study Period of 60yrs (UK) can be changed to 50 for Ireland
• Search box helps you find your materials
• Retained existing materials a checkbox in buttons 1-4 allows you to enter existing materials in retrofit, (RICS requirement) omitting A1-A5, from v6.13. Whenever you add a new material you can enter years delay if the previous material is not yet ready for replacement. This also makes it easy for step-by-step retrofits to be assessed, where sets of materials are implemented in stages, each with the same delay, from v6.13.
• Refine your entries a checkbox in buttons 1-4 allows you to change a material, keeping the quantities, from v6.14. You can also change the density of some materials. e.g. blown mineral fibre, and you can for timber based products you can reduce the assumed 100% FSC/PEFC compliant. Transport distances are estimated, but you can change the category if for example you know the windows are from mainland Europe
• Mac compatible, from v6.13

The main menu below arranges data by RICS category. Each button opens an entry screen, filters the list and goes to the relevant row of the spreadsheet:

Typical entry screens are shown below. After entering you can go back to the main menu or use the category buttons near the title to jump to a related category.

Outputs

• Fully transparent calculation.
• Coloured “heat map” results, the output table is coloured by value to make it easy to see where the CO₂ is coming from.
• Whole Life Carbon CO₂ graph shows operational and embodied CO_2.
• RIBA 2030 Challenge results for operational and embodied
• LETI results and graphic
• UK Net Zero Carbon Building Standard (UKNZCBS), an estimate of the pilot
• WLCA uncertainty factor calculations are now much quicker, PHribbon fills in some of the information for you, v6.14
• Full set of RICS reporting and summary tables, v6.13 or simple categories for a quick calculation
• Advanced use of partial data. Carbon Calculator avoids resorting to a complete RICS estimate for the end of life where there is partial EPD data. For example the RICS requirement for solid timber is 1% reuse, 78% recycling, 20% incineration and 1% landfill. Instead of dismissing completely an EPD that assumes 100% recycled at the end of life, it uses 78% of this figure for the recycling part, meaning that only 22% is estimated using RICS. If the EPD has other 100% options, for example 100% incineration and 100% landfill, it can use them all, only estimating the part it doesn’t have.

Examples of the CO₂ heatmap results:

Examples of Whole Life Carbon CO₂ graphs:

Examples of results to towards UK carbon targets and standards

Minimum System Requirements – You will need:

• Windows or Mac (no need for Parallels or similar software)
• Microsoft Excel from a current version of office, or within last 5 years
• Dropbox or Sharepoint for us to send you updates
• For the operational carbon calcs you will need your own energy software, e.g.SAP (If you have PHPP then use PHribbon)

Upon purchase an e-mail which will be sent to you (within 2 working days) containing instructions on how to verify your sale, obtain a licence key for use and access the CO₂ Calc.

Buying the package with an annual subscription fee

An annual subscription gives you access to continual updates of the AECB Carbon Calculator. Each year about 200 Environmental Product Declarations (EPDs) are replaced, the NESO (National Energy System Operator) scenarios are updated, government CO₂ factors are updated and improvements are made to the usability and new standards, such as the UK Net Zero Carbon Building Standard (pilot). An annual subscription allows us to keep all these changes up to date.

The first year’s subscription fee is included in the purchase price.

Upon the anniversary of your product purchase you will receive a request/invoice to pay the yearly subscription fee.

Discounts

Discounts are available for bulk purchases (more than 4) please email [email protected] for further information.

Discounts are also available for educational institutions – please email [email protected] for details.

TDUK members please use your coupon code at the checkout.

These discounts cannot be combined with the AECB membership discounted price.

Products in the AECB shop are sold according to the terms and conditions listed here.