The Code for Sustainable Homes: Towards Zero Carbon

Alan YatesTechnical Director, BREEAMBRE Certification

Overview

• Based on EcoHomes 2006

• Linked to continuous improvement inlegislation, policy and good practice

• Amended scope of assessment

• Amended assessment criteria

• Post construction certification

• Only covers New build in England

Major differencesEcoHomes The Code

Site Assessment Individual Dwelling Assessment (based on Dwelling Types)

Usually ‘design stage’ only Assessed in 2 stages – design stage and upon completion.

Flexible standards in all categories Fixed Minimum Standards (thresholds) for some categories

Absolute carbon levels Energy based on percentage improvement over Building Regulations

Includes locational credits related to transport and amenities

Locational credits related to transport and amenities omitted.

New points for ‘Lifetime Homes’

Mass market

Environmental Standards

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Code Issue Categories• Energy/CO2

• Water

• Materials

• Surface Water Run-off

• Waste

• Pollution

• Health & Well-being

• Management

• Ecology

• Energy• Potable Water

Consumption

• Waste

• Materials

• Water Surface Run-off

• Pollution

• Health & Wellbeing

• Management

• Energy

• Potable Water Consumption

• Waste

• Materials

• Water Surface Run-off

• Pollution

• Health & Wellbeing

• Management

Trad

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• Waste

• Materials

• Water Surface Run-off

• Waste

• Materials

• Water Surface Run-offM

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• Energy

• Potable Water Consumption

• Energy• Potable Water

Consumption

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OverallScore

Level 1Level 2Level 3Level 4 Level 5Level 6

Weightings

Energy 36.4 %Potable Water 9 %Surface Water Runoff 2.2 %Materials 7.2 %Waste 6.4 %Pollution 2.8 %Health and Wellbeing 14 %Management 10 %Site Ecology 12 %

Code levels and points scoreCode Levels Total Points Score out of 100

(equal to or greater than):Approx equivalent EcoHomes rating

Level 1 () 36 Points Pass (36%)

Level 2 () 48 Points Good (48%)

Level 3 () 57 Points Very Good (58%)

Level 4 () 68 Points Excellent (70%)

Level 5 () 84 Points

Level 6 () 90 Points

Minimum standardsCategories FlexibilityEnergy Efficiency 6 levels of minimum standards one for each level of the

CodeWater Efficiency Three levels of minimum standards each covering two

levels of the Code

Materials A single basic standard at Code entry levelSurface Water Run Off WastePollution No minimum standardsHealth & Well-Being ManagementEcology

Minimum Energy Standards

Based on SAP:2005 calculation and % improvement on 2006 Building Regulations Part LA

Code Level Energy Performance Equivalent standardsLevel 1 10% improvement EST Good

Level 2 18% improvement

Level 3 25% improvement EST Best

Level 4 44% improvement Approx. PassivHaus / EST advanced

Level 5 100% improvement

Level 6 Full Zero Carbon Approx 145% improvement over ADL1A: 2006

Minimum Carbon Dioxide Emissions Standards

Building Regulations Part L1a: 2006• Target Emission Rate (TER) –

minimum requirement• Dwelling Emission Rate (DER) –

actual emissions• 30% dedicated low energy lighting

provision• Compliance with other aspects –

Fabric Backstop standards

Minimum Energy Standards

The Code requirements (as ADL:2006)Levels 1-5• The % improvement in the actual emissions over the

target emission for each Code Dwelling type.• i.e. [1-(DER/TER)] *100%

• Accredited energy assessor/Part L ‘competent person’- The term ‘SAP Assessor’ is to be replaced

• When a building contains more than one dwelling, area-weighted average DER and TER for the building as a whole is acceptable (as described in clause 23 of Approved Document L1A).

Minimum Energy Standards

The Code requirements (as ADL:2006)Level 6 – Where net Carbon Dioxide emissions resulting from ALL energy use in the dwelling is Zero.• Must meet Level 5 threshold by on site means• Heat Loss Parameter (HLP) of ≤0.8m3/hr/m2

• Appliances demand can be met • by on site renewables/low carbon technologies• OR by off site independently accredited renewables

• Some ESCOs comply where directly supplying• Definition very similar to HM Treasure Stamp Duty

relief

Ene 1 – Dwelling Emission Rate% improvement of DER over

TER Credits Mandatory Levels

≥ 10 % 1 1

≥ 14 % 2

≥ 18 % 3 2

≥ 22 % 4

≥ 25 % 5 3 (ADL:2010)

≥ 31 % 6

≥ 37 % 7

≥ 44 % 8 4 (ADL:2013)

≥ 52 % 9

≥ 60 % 10

≥ 69 % 11

≥ 79 % 12

≥ 89 % 13

≥ 100 % 14 5

True Zero Carbon 15 6 (ADL:2016)

Passiv Haus Standard – UK StandardPassivHaus UK Standard Practice

U Values < 0.15 W/m2/K 0.25-0.35 W/m2/K

Energy Efficient Glazing < 0.80 W/m2/K50% heat gain coefficient

< 1.80-2.2 W/m2/K

Air tightness < 1 m3/hr/m2 @ 50Pa 7-10 m3/hr/m2 @ 50Pa

Passive ventilation preheating

Ground ducts and/or heat recovery

None

Passive solar Key design factor Limited

Lighting Low energy lighting throughout

30% low energy lighting required

TOTAL Energy space heating

< 15 kWh/m2/yr Typically 55 kWh/m2/yr

Minimum Carbon Dioxide Emissions Standards

The following are not covered within SAP at present but can be taken into account:

• Cooling• LZC technologies not covered by SAP• Newer low energy technologies

• Lighting• Appliance loads

Tradable Credits

Tradable credits awarded:

• for higher performance levels in some key issues

• for remaining issues

– Broadly as in EcoHomes 2006

– Location issues omitted

– Some additional credits

Tradable Credits - Energy

Ene 1 - Dwelling Emission Rate (DER) Additional credits available for achieving a

higher scale percentage improvement over Building Regulations

Credits based on % improvement above Building Regulations part L1a instead of actual CO2/m2/year as under EcoHomes 2006

Tradable Credits - Energy

Ene 2 - Building Fabric• Credits awarded based on the Heat

Loss Parameter obtained from the SAP calculations

• HLP ≤ 1.1 or 1.3

• Same as EcoHomes 2006

Tradable Credits - Energy

Ene 3 - Internal Lighting• Credits awarded based on the % of dedicated

energy efficient light fittings• 40% or 75% dedicated low energy light

fittings

• Same as EcoHomes 2006

Tradable Credits - Energy

Ene 5 - Energy Labelled White Goods• Provision of specific EU Energy Efficiency

Labelled white goods or • EU Energy Efficiency Labelling Scheme

purchasing information.

• Same requirement for social and private housing

Tradable Credits - Energy

Ene 6 - External Lighting• Credits awarded based on the

provision of dedicated energy efficient light fittings

• Or security lighting with movement detectors and daylight shut-off devices

• Same as EcoHomes 2006

Tradable Credits - Energy

Ene 7 - Zero/Low Carbon Technologies• Credits for Zero/Low Carbon technologies

where they make a significant contribution to the energy demands

• 1 credit: 10% carbon dioxide reduction• 2 credits: 15% carbon dioxide reduction

• 2 instead of 3 credits• Credits for feasibility study only dropped• Off site generation may be accepted under

certain criteria

Tradable Credits – Other Categories

• Potable water consumption• External water consumption• Daylighting• Drying Space • Home Office• Cycle Storage• Materials – embodied impacts including

CO2

• Home User Guide• Building Footprint

Achieving Code Level 1

• Energy – 10% improvement over TER• Meeting the Energy Requirements

– Improved thermal efficiency of building fabric– Reduction in air permeability– High efficiency condensing boiler– Reduction of thermal bridging

• Other mandatory requirements

• Additional 33 optional points

Achieving Code Level 3

• Energy – 25% improvement over TER• Meeting the Energy Requirements

– Measures outlined for Code Level 1– Maximum benefit from cost effective ‘conventional’ solutions to fabric and

systems efficiency– + possible use of low or zero carbon technologies in some cases

• Other mandatory requirements

• Additional 47 optional points

Achieving Code Level 4

• Energy – 44% improvement over TER• Meeting the Energy Requirements

– High performance building fabric and efficient systems/controls– + some use of low or zero carbon technologies

• Other mandatory requirements

• Additional 54 optional points

Achieving Code Level 5

• Energy – 100% improvement over TER• Meeting the Energy Requirements

– High performance building fabric and efficient systems/controls– + significant use of low or zero carbon technologies (individual dwelling or

community system). – No off site renewables unless independently accredited and ‘additional’.

• Other mandatory requirements

• Additional 60 optional points

Achieving Code Level 6

• Energy – Approximately 145% improvement over TER• Meeting the Energy Requirements

– Optimal performance building fabric and systems/controls– use of low or zero carbon technologies (individual dwelling or community

system). – Likely to include use of off site renewables but must be:

• independently accredited• ‘additional’.

• Other mandatory requirements

• Additional 60 optional points

A Two-stage Process

• Design Stage– Based on design drawings, specifications and

commitments – Results in interim certificate of compliance

+

• Post Construction Review– Based the design stage information– Confirmation of compliance through site

records and visual inspection.– Code certificate awarded based on compliance

at this stage.

BRE – Innovation Park Houses

Food for thought

• Achieving zero carbon is not easy but it is achievable

• We have limited experience to date but a lot of knowledge to help

• Code presents a tool for measuring and evaluating performance