Here is a breakdown of the key changes that will affect not only SAP Calculations for new dwellings but it will also SAP calculations for extensions and SAP calculations for conversions. 

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The 8 key areas affected by the upgrade from SAP 2012 to SAP 10 (introduced from June 15th 2022) are:

 

• Cost & Carbon Emission Factors for Fuels

• Community Heating:

• Hot Water Systems 

• Airtightness Testing Methods 

• Mechanical & Ventilation Systems Changes 

• Lighting changes 

• Photovoltaics 

• Detailed photographs required during the build

 

Here are those 8 areas in more detail to help you plan your next project to comfortably pass its SAP Calculations:

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Cost & Carbon Emission Factors for Fuels

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The most stand out change to SAP 10 compared to SAP 2012 has to be cost and carbon emission factors. For example, here are the cost factor changes presented as a %, compared like for like with SAP 2012:

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• Mains Gas +6%

• Oil -9%

• LPG -11%

• Electricity +25%

 

So, based on those numbers a house that was a steady 80C in SAP 2012 would now be (based on SAP 10):

• Gas         C80,

• LPG        B81

• Oil          B81

• Elec        D67! 

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Therefore, improvements in specification will be needed to bring the house up to a pass based on Part L 2021.

Lets now look at Carbon Emissions updates in SAP 10. Again, the figures are presented in % change from SAP 2012 for comparison:

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Gas (-5%)

Oil (minor change)

LPG (minor change)

Electricity (-74%)- This whopping cost change saving reflects the uptake over the last decade in renewable energy used in generating electricity.

This would mean: A house currently achieving 80C in SAP 2012 would now rate as:

Mains Gas 82B (+2 points) ,

LPG 81B (+1 point)  ,

Oil 81B (+1 point)

Electricity 98A (+18 points)!!

 

Essentially a low cost property may not be low carbon and vice versa!

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Community Heating:

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In SAP 10 the main change here from 2012 is the options from ‘community heating’ to ‘Heat Networks’ to reflect the uptake of these systems in inner city areas. There are also 5 new heat recovery options introduced into SAP 10:

• Heat recovered from waste combustion

• Heat recovered from power stations

• High grade heat recovery

• Low grade heat recovery

• Heat recovered from geothermal & other natural sources

 

These new options are in anticipation of the move from fossil fuels over the next decade and the planned move towards low carbon alternatives.

Hot Water Systems

Now includes more detailed calculation of water demand and includes:

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• No. of baths

• Source of cold water

• Flow Rates/ power use of showers

 

A word of warning though... This information was not required previously, therefore care will be need at the ‘As Built Stage’ calculations. to ensure these details were implemented from ‘As Designed’ calculations. As water is considered a high use of energy there would be a significant impact to the SAP calculations if missed or changed. 

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Airtightness Testing & Mechanical Ventilation Systems

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Air tightness Testing: Inclusion of ‘Pulse’ testing method alongside blower door method.

Part F 2021 states if a home now has an airtightness result of '˂3' a continuous mechanical extract ventilation system or supply & extract with heat recovery should be used.  SAP 10 allows for more details of these systems to avoid defaults which previously could penalise a system. Specific fan power & ductwork insulation can now be added to bring the efficiency of the system into the calculation.

In summary the air tightness testing and mech. vent systems are closely linked and a suitably spec’d selection of a vent system is rewarded in SAP 10.

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Lighting

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Quite large changes in this section. There is a move from the original option: amount of ‘low energy lighting’ (most domestic lighting available is low energy today), to a more detailed approach. We will need to now include details for each fixed light. As you will be aware this is quite a new approach for all of us. The new details required include:

• Luminous efficacy (lm/W) –(Higher value reflects better efficiency)

• Power (W)

 

Multiple fittings of the same type will be able to be entered in 1 entry and adjusted to the quantity. Defaults can be applied for the Luminous Efficacy if unknown at Designed Stage Calculations but as usual these will show a lower level of performance. The Power figures (W) however will be needed as no default option will be available in SAP 10.

What new evidence will be needed? I suspect a detailed lighting schedule listing the models of fittings and their performances would be great, alternatively a lighting plan with lighting locations supplied which could be cross referenced with associated documents of lighting types would also suffice.

This is quite an industry change and I’m sure if we are not careful here there could be a few caught out when the project and SAP Calculations moves to ‘As Built’.

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Photovoltaics

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PV has now been introduced on the ‘notional dwelling’. Modelling has shown that dwellings heated by gas, LPG, Oil or direct electric heating are most likely to require PVs to achieve compliance.  SAP 10 has now included more details to reflect the diversity in this area allowing the following to be entered thus giving a more accurate calculation:

• More accurate calculation method

• Increase in connection scenarios to allow for PVs serving one or multiple dwellings

• Microgeneration Certificate Scheme (MCS) Shading Factors

• PV Diverters

• Battery Storage reductions

• Meter Type (Now capable of including options such as exporting to grid)

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Photographs 

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Please read my blogpost for details on what photographs are now required to accompany your SAP calculations.

 

Wow! Welcome to SAP 10 which reflects the changes in Part L. I hope this page has been helpful, please contact me directly if you have any questions. 

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To learn more about the differences between SAP Calculations for New Build Projects vs. SAP Calculations for extensions follow this link