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GBC > Q&A > C#344

Your Questions

My directors have asked me to look into the Green Building Calculator and I was wondering whether you could please help me with a few queries I have?

Thank you for your Director’s enquiry, very happy to answer.

In your description it says that it provides cost information of different materials.
Where does this information come from?
Is this something that we will have to get from manufacturers and input it manually or does it connect to a database?

Initially the file is populated by your own enquiries from manufacturers and suppliers
At Tender stage it can be populated by your tenderer/contractor as a pricing document
This information could be used to populate your own rough prices look up table
I had originally considered Spon pricing books but the discussions I have had suggest these are not reliable enough and may be contributing to QS’s poor cost planning and the ‘race to the bottom’ our industry is experiencing.
I will seek Manufacturer’s and Suppliers support to populate the products spreadsheets with cost data.
There is a QS who wanted to build the Green Building Price Book 20 years ago, if GBC takes off and generates revenue then I will ask him to reengage with his ambition and embed it in GBC.

How it compares with the PHPP software?
I understand that this calculator explores different heating options and doesn’t rely solely on a heat recovery system like Passivhaus, but in terms of the other calculations it does, how does it compare?
Does it have the same extent of calculations?
My practice is unclear on which licence to purchase.

This is not equivalent to PHPP, however you can get an impression of what PH or EnerPHit (or AECB’s Carbon Lite & CL Retrofit) will do to your building’s U values, Insulation thicknesses, if you choose it as your energy target.
Whilst PH is a great route to low energy in use, I know many may not go that way and may focus on lowering embodied carbon (EC) raising sequestered carbon and IUC in use carbon.
I have developed the whole building & elemental calculators to determine the demand heat source(s) size
I have also developed the room by room calculator to work out radiator/UFH coil sizes or start with boiler size and work out insulation thicknesses to match the boiler.
This version of GBC calculator does not have a Services Design Function yet (Version 16 unless I bring it forward, I probably will)
I have met the man who can help me to build this module, I will engage with him once version 2 is published.
I am adding a Services Bill of materials/quantities/costs, EE EC & LCA in version 2 (bringing parts from v3 and v6 sooner)

PHPP software compares the calculated version to the Passivhaus criteria (so gives a benchmark).
In your description it says it does a comparison with different standards.
Does this mean that it will provide the various criteria for Passivhaus, BREEAM etc?

After a Form factor calculation you are promoted to set your U value targets, then you choose between Regulations, which should be local to the project (e.g. E & W, S or NI or other national standard) and design standards: UK GBC, ZCH, PH EnerPHit, CL, CLR, Minergie, etc. targets
You choose and set targets, the U values permeates the calculator, when you assemble your building elements it tells you Pass, Unregulated Pass or Fail.
This may equate to your benchmarking?
You can then adjust insulation thicknesses to get Pass all round.
You should use PHPP for PH calculations not GBC.
This calculator will help with some BREEAM area calculations and speed up some of the tedious fruitless calculations.
These calculations are useful as part of the design process, rather than totalling up and changing nothing.
Version 2 will have LCA calculations in it. (Brought forwards)
This is based on your own elemental assemblies, so it is not restricted to the 1200 or so in Green Guide to Specification.
You get an instant answer without waiting for BRE to so their bespoke calculations for you.
In time GBE Product datasets will have useful data to support Passivhaus, BREEAM, etc.

Version 1 was released June 2020
Version 2 will be Spring 2021
Version 2 is being developed with Embodied Energy, Embodied Carbon, Sequestered Carbon, LCA, Bill of materials, Quantities, etc.
Version 2 should be the one that is needed by many
Version 3 functions are mostly included in the latest scope of version 2
Do let me know which functions are of interest from version 3 if any have been missed out.

© GBE GBC GBL NGS ASWS Brian Murphy aka BrianSpecMan **
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14th September 2020 – 9th January 2021