SAP Calculations

[le-cerveau]

Has anyone ever done a manual SAP calculation?  I have just finished it (lots or excel work that I can maintain and update) and want to make sure I have some sensible answers.  Here are some key points:

Total Floor Area:	414.29m2
Living Floor Area:	107.39m2
Dwelling Volume:	1077.88m3
Window Area:	50.5m2	U-values 0.8 – 1.04 (PHPP calculations)
Door Area:	10.62m2	U-value 0.73
External Wall Area:	345.4m2	U-value 0.10-0.11
Roof Area:	355.8m2	U-value 0.11
Thermal Bridges:	7.85W	Design
	26.66W	TFEE
	Design	FEE	TFEE
Effective Air Change Rate:	0.15	10.23	10.52
Heat Loss Parameter:	0.508 W/m2K	9.162 W/m2K	9.563 W/m2K
Water Heating required:	2837 kWh/year	2404 kWh/year	2837 kWh/year
Internals and solar Gains:	1540-2711 W/month	1396-2423 W/month	1612-3322 W/month
mean Internal temp:	20.22-20.49oC	13.59-14.97oC	17.76-19.02oC
Space Heating required:	1.17 kWh/m2/year	11.64 kWh/m2/year	11.94 kWh/m2/year
Space cooling required:	0.64 kWh/m2/year	0.06 kWh/m2/year	0.04 kWh/m2/year

Giving a Fabric Energy Efficiency of:
1.81 kWh/m²/year           Design
11.70 kWh/m²/year        FEE
13.77 kWh/m²/year        TFEE

So my designed Fabric Energy Efficiency is far better than the notional Dwelling Fabric Energy Efficiency Rate let alone the Target Fabric Efficiency rate, so I am ok there.

On CO₂ emissions the Target Emission Rate is 7.37 and the Design is -1.11 or -1.89 depending on how I calculate the DHW, so again well under.

So my calculated ratings are SAP A (100-102), CO₂ A (101-103) and Primary Energy A (109-115).  The variation is based on DHW higher figure for pure Gas DHW, the lower if is assume half provided by ASHP pre-heat (but I will have to get authorisation for that).

Is this the sort of answers I should be getting?

Edited November 23, 2016 by le-cerveau
changed windoww mm to m

[PeterW]

Not sure if the Window one is a typo but it says mm2

 

Other than that is this a spreadsheet you've built or an extract out of fdSAP or something similar..?

[le-cerveau]

I have build my own spreadsheet 40, tabs and counting.  I tried one of the free SAP programmes but they came up with gibberish in one field of another.  It has taken me a few weeks to work through the SAP2012 regulations and create my own formulas, but I got there.  It was made easier by having all the details in PHPP to extract info from.

[ADLIan]

Difficult to say if the numbers are making sense without knowing the raw input data in detail.

 

Unless you are very good with Excel and understand the complexities of SAP in great depth I wouldn't bother compiling my own spreadsheet!!

 

Also remember that SAP software should be BRE approved - this ensures all software from all suppliers is churning out the same results. Without some form of checking against recognised sofware your spreadsheet may be giving meaningless numbers.

 

Software, even free trial versions, from the major approval bodies should give a warning if wrong info is used - if you are getting erroneous figures either the software is not up to scratch of you need to study the SAP document in more detail - insomnia cured!!

 

Ian

[Guest Alphonsox]

I would suggest comparing your result against the Stoma free version

https://www.stroma.com/software/sap-software-fsap

[Barney12]

I fell across this online:

 

http://www.s147629948.websitehome.co.uk/saponline/documents/SAPDataForm.xls

 

Is that all that's needed (plus dimensions) for a basic new build SAP Calc? 

[Guest Alphonsox]

That looks like the basic input data (It's missing a few parameters, Lamda, Renewables, Chimeneys etc, ) - then "all" you need to to is to calculate the results.

[dogman]

Another one is the NHER plan Assessor. You get a month free trial. Do your design stage yourself as you do not need to be qualified. You get a professional looking file for building control. Send your copy to an online assessor once built who will do the as built and SAP/EPC for about £80

 

I found NHER the easiest to use

[Barney12]

37 minutes ago, dogman said:

Another one is the NHER plan Assessor. You get a month free trial. Do your design stage yourself as you do not need to be qualified. You get a professional looking file for building control. Send your copy to an online assessor once built who will do the as built and SAP/EPC for about £80

 

I found NHER the easiest to use

 

Thanks will take a look. 

[ADLIan]

@Barney12 Lots of information missing from the linked spreadsheet, it barely scratches the surface of the required input data!!

 

An accredited asssessor should not accept the input data from any 3rd parrty - not even another accreedited assessor. Any errors are then yours and continued accreditation may be at risk. Personaly I value my professional reputation, status and accreditation too much to risk this course of action. A good asssessor will not just do the number crunching but will also offer independant advice and guide you through the myriad of options available under SAP.

 

I use NHER Plan Assessor and find it a great bit of software. Elmhurst is good too just takes ttime getting used to sometihng different.

 

Ian

 

 

[le-cerveau]

The numbers I listed are not the complete set, that would take forever to duplicate in the post, just some of the generic.  I have all the values listed in the SAP 2012 guide.  I will give some of the suggested ones a try.

Thanks

[le-cerveau]

I have finally got round to putting the details in STROMA SAP and it came up with:
Predicted EPC of EER 116 and CO₂ 115.

The TER was 13.91, DER -11.5, FEE 40.56 and Reduction in CO₂ emissions of 119.8%.

I have attached the EPC and CSH reports:

Rose Lane-Predicted EPC.PDF

Rose Lane-CSH Report.pdf

So it seams I was in the right ball park.

Having all the details in PHPP made it easier to insert into the software.

[le-cerveau]

I now have my As Designed SAP grades ready for building control submission:

 

 

Even better than my calculations and this is from the official SAP assessor!

I am sure something will change (reduce the PV on the roof for example) but it is a good starting point.