SAP befuddlement

[Raine]

 

I'm at planning stage.  LA planning policy requires new dwellings to "achieve at least a 40% reduction in carbon emissions from a 2013 Building Regulations (or future equivalent legislation *) compliant base case". 

* I.e. now 2022 regs.

 

I've had my design-stage SAP calcs done but I'm struggling to interpret what I've been sent, and the SAP assessor keeps sending me answers that make no sense to me, so I think I'm fundamentally missing something.

 

I'd be grateful if any of you are able to check and correct my understanding, please:

 

• I understand that TER is the figure for a notional regs-compliant building of the same size and type, right?  So, as long as I meet or improve on this figure, I comply with the regs, yes?

 

• I assume the term "baseline" means the TER??
  • For the 40% improvement required for planning, I assume I just do TER * 0.6?

 

• The SAP assessor has told me which figure is 'the 40% improved figure', but that figure is 65% better than the TER, not 40%, so I can't see how that's right.  He replied saying:

  • "The reason we use TER for the baseline is that the baseline assumes a mains gas boiler, in SAP10 you need a lot of solar PV to make the DER compliant which skews the figures.  Prior to SAP10 we would have just used the DER from the basline & proposed models as a direct comparison to demonstrate the % reduction. This is not possible in SAP10".

  • I have no idea what he's talking about!

 

Is there an idiot's guide that you can point me towards that will explain this?

 

[ProDave]

Ask the council.

 

If they don't know then it won't matter what you submit.

[MR10]

52 minutes ago, Raine said:

 "achieve at least a 40% reduction in carbon emissions

 

• The SAP assessor has told me which figure is 'the 40% improved figure', but that figure is 65% better than the TER, not 40%, so I can't see how that's right.  reduction. This is not possible in SAP10".

 

Looks to me like your improvement is better (65%) than the minimum 40% required. Just submit the report/figures as provided and move on to other things.

[kandgmitchell]

The chances are the planners will have no idea what the figures mean either but if they are presented by your SAP assessor they'll take them as complying.....

[Dave Jones]

have a look at other applications submitted and copy one of them.

[ADLIan]

Planners make up these rules but haven’t got a clue what they are actually asking for. In the absence of specific guidance from them if the DER is 40% better than TER then box ticked, move on…. Your SAP assessor is just confusing the issue, how you get the 40% uplift matters not to the planners.

[nod]

It’s just a meaningless box ticking exercise When you are all built and ready for sign off You will have to go back to this guy or someone else for the final sap report Which is totally reliant on the information that you give them For example You they will ask you if you have updated insulation 

and u values for your cheap safe style windows that you put in Never mind you can always send them the expensive quote that you could afford with the treble glazing and double seals He won’t need payment details Just the U values 

 

Money for old rope 

[Raine]

 

All understood, but I need to include the relevant figures in my energy statement, which I can't do if I don't know which is which.

 

Maybe you're right though, and I should stop trying to do it "right" and just cherry-pick the most favourable figures at any point in the design and build process and go with those.

 

In the meantime, I'll look on Google for some beginner's guides to SAP and see what I can find to read in my spare time.

 

[JohnMo]

Simple don't overthink it

 

Draw up plans, get a design stage SAP report. It will pass or fail BR requirements.  If you feel you would like to improve or change things at the design stage, the assessor will update.  Build house, get an as built SAP done - finished.

 

Comment - tell the architect what you want to achieve, basic building Regs (daft in my opinion) or an A or something in between, he should know enough to make it happen, if he doesn't think about moving architect.

[MR10]

4 hours ago, Raine said:

 

All understood, but I need to include the relevant figures in my energy statement, which I can't do if I don't know which is which.

 

Mine was in the design u value calculation, see image below. I just took the figure next to the %DER<TER and included it in my energy statement.

[Raine]

 

This is from the doc named "baseline":

 

 

This is from the doc named "as proposed":

 

 

I was expecting either one or two TERs (one for 2022 Regs and possibly also one for the Planning requirement of 40% improvement) and one DER.

 

There are two TERs, but the lower figure isn't a 40% improvement on the higher figure, so I don't know what they are.

 

And there are two DERs, and I have no idea why, other than I presume the lower figure is my proposal, as he said it passes.

 

Is it just me, or is this hard / impossible to figure out what's what without being told?

 

I know you all say "forget it and move on", but I'm the type of person who likes to understand things (not every detail, but at least to some extent), and also, I might want to down-spec a bit to save costs in some areas.  

 

[ADLIan]

I'm not sure exactly what is being shown there. The 'baseline' may be the 'notional' building used as the benchmark to compare your actual proposed dwelling (see Table 1.1 in AD L1). As mentioned before the Planners will look at this very simply (unless they have more detailed requirements which is doubtful). The important numbers are those for your 'proposed' house - a 40% reduction in the DER here is normally sufficient for the Planners. I note the main fuel is electricity do you have lots of solar PV or using a heat pump to get the CO2 emissions down?