Prof. David Strong, Chief Executive, Inbuilt Ltd. Good Homes Alliance Christmas Event, The Princes Foundation9th December 2009

SAP, Building Regulations and the Code

Regulatory and other key drivers in the UK

Policy framework

• Climate Change Act: legal obligation on Government

• CLG consultation on Zero Carbon Definition• Minimum energy efficiency standard• Heat &Energy Saving Strategy • EC initiatives: Energy Using Products

Directive, EPBD Mk2• to name a few ........

Policy framework

Timetable for new homes:• 25% improvement in 2010 CSH energy level 3• 44% improvement in 2013 CSH energy level 4• Zero carbon from 2016 CSH energy level 6

Key changes to SAP

• Fully monthly calculation

• Updated weather file

• Revised emissions factors

Biomass (pellets)

Gas(kg/

kWh)LPG Heating

OilHouse Coal

Electricity(kg/kWh)

SAP 2005 0.13 1.00

(0.194) 1.21 1.37 1.50 2.18 (0.422/0.568)

SAP 2009 0.18 1.00

(0.206) 1.22 1.38 1.85 2.87(0.591)

• CO2 equivalent• Upstream emissions

• Liquid biofuels included

• Boiler systems – modification to SEDBUK– Different summer and winter

efficiencies

• Thermal mass and cooling (regionality)

Key changes to SAP

Key changes to SAP

• Hot water use – same volume but cooler

• Auxiliary energy use– energy use– energy gains

• Occupancy – more crowded than we thought!

Key changes to L1A

Same general 5 step approach – familiar and welcome

• DER ≤ TER • Limits on design flexibility• Limiting the effects of solar gains in summer• Quality of construction & commissioning• Providing information / O&M instructions

1. DER ≤ TER

X 0.75 = Target 2010

Target2006

Adjusted for - New CO2 factors

Party wall bypass

2.Limits on design flexibility

• Largely unchanged

• Updated building series compliance guide

• Methods to stop easy compliance with renewables

3. Limiting impact of solar gain in summer

• SAP - 3 separate months assessed• Cooling demand calculated regionally• Test applied even if cooling installed• Policing – need much greater attention

3. Limiting impact of solar gain in summer

• Shading

• Reduce internal gains

• Add mass where possible

• Night ventilation

Education for designers (and planners?)

4. Construction & commissioning

Airtightness• Doubled sampling rate• Changes to testing regime

Thermal bridging• ACD scheme in the making?

Commissioning plan required

Improving compliance and confidence

• Energy Assessor checks• BCB provided with a specification – not just a

sheet of U-values• Margin added to non-pressure tested units• Margin added to ‘non-accredited’ details

Part FADF 2006 only designed for 3 m3/h/m2 @50PaHowever AECOM study showed:• 52% of door undercuts less than 10mm• 72% of trickle vents areas less than ADF• 89% of kitchen extracts less than ADF and 79%

of batroom extracts less than ADF• Overall 55% of dwellings have ventilation rates

less than ADF. • Can local extract be trusted?

Part F• In eight out of nine dwellings, the MEV

systems failed to achieve their design flow rates, in some cases by as much as 63%

• Can mechanical ventilation be trusted?

How airtight are our homes?

Part L study• ~30% of new dwellings tested < 5 m3/h/m2 @50 Pa• ~3-5% of new dwellings tested < 3 m3/h/m2 @50 Pa

NHBC data• ~70% < 7 m3/h/m2 @50 Pa• ~40% < 5 m3/h/m2 @50 Pa

• Need robust approach to ventilating new homes

ADF new requirements

For dwellings designed to an air permeability of 5 m3/h/m2 @ 50 Pa or tighter:

• Extract vent (local, PSV and MEV) - bigger trickle vents

• PSV – bigger duct sizes• MVHR

– Increased air flow rate requirements

ADF new requirements

For new dwellings only, new requirements for:• Air flow rates of mechanical systems

(including intermittent extract fans) should be measured on-site.

• Owner to be given information to operate and maintain natural and mechanical systems properly

• Check list to be given to building control body as evidence that all the above have been done

Code for Sustainable Homes

• Faster delivery of certification• Bringing forward some of the evidence• Greater stability – too many versions• Lifetime homes• Conflicts with Passivhaus and innovative housing

– interpretation of requirements varies

Summary• Beware!

- The Law of Diminishing Returns- The Law of Unintended Consequences- Murphy’s Law

Prof. David Strong, Chief Executive, Inbuilt LtdE-mail: david.strong@inbuilt.co.uk

Tel: 01923 277061

www.inbuilt.co.uk