U Value Calculator

[Shortnort]

It would be of great value for architects and engineers to have the capability of performing exterior wall, roof and floor U calculations.  BIMTech Tools offers this as an add-on for Revit and Archicad.  

[Tom W.]

Have you tried Energos?

[Tamsin Slatter]

Energos is built into Vectorworks Architect.

[Tamsin Slatter]

You can find out more here:
https://university.vectorworks.net/mod/scorm/player.php?a=349&currentorg=articulate_rise&scoid=698

[E|FA]

I haven’t done it, but I’m guessing you could also create a worksheet reporting exterior wall and opening areas, etc. 

[Shortnort]

Thanks for the input.  I viewed the video and Energos looks promising. Can the data be exported into Comcheck?  All projects in this area require Comcheck Compliance (International Energy Conservation Code IECC) which is a US Department of Energy software program.

[Shortnort]

Thanks for the input.  I viewed the video and Energos looks promising. Can the data be exported into Comcheck?  All projects in this area require Comcheck Compliance (International Energy Conservation Code IECC) which is a US Department of Energy software program.

[Shortnort]

I have played around with Energos this morning with a small simple building.  Why do I always get "The Total Relevant Floor Area is Zero" message?  I have a floor slab, walls, a few windows, one large "space" and a roof slab.  I have filled in all of the settings (or I think I have).

[Tom W.]

31 minutes ago, Shortnort said:

I have played around with Energos this morning with a small simple building.  Why do I always get "The Total Relevant Floor Area is Zero" message?  I have a floor slab, walls, a few windows, one large "space" and a roof slab.  I have filled in all of the settings (or I think I have).

 

Does your model include Spaces...? Energos needs Spaces to function.

[Shortnort]

I added one space and assigned net and gross heights.

[Cadplan Architecture]

I haven’t tried Energos but may so do now.
 

My approach for individual domestic projects is to use a manufacturers’s online U value calculator. This has the advantage that you then receive an email with PDF a confirming the build up and U value that you can then use in various ways, eg dropping into your building plans PDF ready to send to BC for plan checking.

 

I have steered away from specifying the two largest PIR manufacturers and now use the Recticel calculator. Unilin (was Xtratherm), Ecotherm and others in the UK have similar calculators.

 

[Tom W.]

53 minutes ago, Cadplan Architecture said:

I haven’t tried Energos but may so do now.
 

My approach for individual domestic projects is to use a manufacturers’s online U value calculator. This has the advantage that you then receive an email with PDF a confirming the build up and U value that you can then use in various ways, eg dropping into your building plans PDF ready to send to BC for plan checking.

 

I have steered away from specifying the two largest PIR manufacturers and now use the Recticel calculator. Unilin (was Xtratherm), Ecotherm and others in the UK have similar calculators.

 

 

You can do this within VW very easily. If you use Materials + include K-values for the products/materials the U-value for Walls/Slabs/Roofs will be calculated automatically + can be returned in reports, Data Tags + Graphic Legends.

[line-weight]

35 minutes ago, Tom W. said:

 

You can do this within VW very easily. If you use Materials + include K-values for the products/materials the U-value for Walls/Slabs/Roofs will be calculated automatically + can be returned in reports, Data Tags + Graphic Legends.

 

I didn't know this was possible within VW. Does it deal properly with bridged layers and can it do condensation risk calculations too?

 

Is it possible to post an example of the kind of output it gives?

[Tom W.]

25 minutes ago, line-weight said:

Is it possible to post an example of the kind of output it gives?

 

A Wall, Slab or Roof gives you the R-value of the components based on the inputted K-value for the component or the Material the component is using + the thickness of the component. This is displayed in a column in the Components dialog. You can then returned the combined R- (or U-) value of the whole Wall/Slab/Roof (the build-up I mean) in a report/Data Tag/Graphic Legend e.g.:

 

 

31 minutes ago, line-weight said:

Does it deal properly with bridged layers and can it do condensation risk calculations too?

 

Energos is what you'd use for more sophisticated modelling, I'm just talking about very basic U-value calcs for different build-ups, but I've never used it so can't say much about it. I believe it does deal with thermal bridges but don't think it deals with condensation risk. Energos is based on PHPP + I don't think PHPP covers condensation risk does it...? Isn't that where WUFI comes in...? I know very little about all this so others will be able to advise better. I'm generally quite content to just know the R-value of the walls, roofs + floors. I would like to give Energos a go one day but am waiting for the right project.

[line-weight]

By bridged layers I mean layers where there is insulation but it is interrupted by things like framing - typical example being a stud wall with insulation between the studs. In that case the U-value calculator needs to know the size & material of the studs, and the spacing between them, so as to give an overall value for that layer of the construction.

 

Also (in theory at least) U-value calculations produced for building regs in the UK are supposed to be done according to a certain BS, which the ones from the manufacturers (and a few free online ones) at least claim to do. My guess is the VW calculation doesn't comply with that, although whether that really matters in practice I don't know.

[Tom W.]

31 minutes ago, line-weight said:

By bridged layers I mean layers where there is insulation but it is interrupted by things like framing - typical example being a stud wall with insulation between the studs. In that case the U-value calculator needs to know the size & material of the studs, and the spacing between them, so as to give an overall value for that layer of the construction.

 

Yes this is covered by the use of Materials. So you would assign a Compound Material to a timber-framing-with-insulation Wall component + this Materials would consist of two Simple Materials: one for the stud work + another for the insulation. Then within the Compound Material you set a percentage to either based on the quantity of wood relative to the quantity of insulation depending on the stud centres. The R-value is calculated for the overall (Compound) Material accordingly + factored into the overall calculation for the Wall.

 

This means you need a big library of Materials but it's quick + easy to create them + makes Walls/Slabs/Roofs/etc incredibly powerful in return.

 

37 minutes ago, line-weight said:

Also (in theory at least) U-value calculations produced for building regs in the UK are supposed to be done according to a certain BS, which the ones from the manufacturers (and a few free online ones) at least claim to do. My guess is the VW calculation doesn't comply with that, although whether that really matters in practice I don't know.

 

For me the VW data is there for my benefit at design stage. I still need to go to external consultant for SAP report for BC. I'm not sure how rigorous SAP/EPC calculations are. 

[Shortnort]

Back to my original question - will VW try to incorporate Comcheck Analysis per IECC in the future like Revit and Archicad?

IECC is only concerned with the value of the encapsulated volume of the project (floor slab to top of roof insulation.  As seen below, my exterior walls have numerous materials, heights, etc. which make converting Energos quite difficult.

 

Below is a Comcheck done on another project to give those not familiar with the program an idea of what is required in terms of data input: