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Domestic Workshop

On Construction – Part L

Stuart Fairlie C Build E, MCABE Technical & Operations Director, Elmhurst Energy

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L1A

“Conservation of Fuel and Power”

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What is it trying to regulate?

• Delivered energy to the home?• Energy consumed in the home? • Carbon emissions?• Warmer homes?• Lower fuel bills?• Climate change?

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Current Regs (2 x Targets)

• Carbon Target• Fabric Target

• & Minimum Standards for fabric and services

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Proposed New Regs (3 x Targets)

• Carbon Target• Primary Energy Target• Householders Affordability Rating

• & Minimum Standards for fabric and services

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How far to go?

21% or 30% better on carbon target

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Why are we changing them?

• Unintended Consequences• Performance Gap (paper v reality)• Climate Emergency• SAP model needs updating• The ‘EU’ made us do it!?

• All of the above

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Future Homes Standard

• What is it?• End of fossil fuel in new build 2025• 75-80% less carbon than one built today• The proposed Changes (F & L) are a

transition to this

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Part F (Ventilation)

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Ventilation Part F

• Large proportion of houses have inadequate levels of ventilation

• Compliance is very poor.

• Driven by a desire to improve SAP ratings, developers will focus on air tightness,

• Results in damp and poor indoor air quality.

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Airtightness

• “Simplify” guidance - setting a room by room approach

• Require design and commission documentation to be provided to the building owner

• It is proposed all new dwellings are tested• no more sample testing.• no small sites exemptions.

• Introducing an alternative test method to the Blower door test called ‘Pulse’.

• Reassigning ownership of the air tightness testing methodology to CIBSE

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Part L (Fuel & Power)

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Option 1 “Future Homes Fabric”

• An average 20% uplift on current standards.

• Typically can be achieved with very high performing building fabric.

• Notional Targets based around;• Triple glazing u-value 0.8 w/m2k, • Wall u-value 0.15 w/m2k, floor & roof 0.11 w/m2k,• Air tightness of 5 m3/m2/hr @ 50 Pa,• Mains Gas boiler, • WWHRS

• An average increase to build cost of £2,900 per plot.

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Option 2 “Fabric plus Technology”

• An average 31% uplift on current standards.

• Has slightly lower fabric standards than option 1, but includes renewables.

• Notional Targets based around;• Double glazing u-value 1.2 w/m2k, • Wall u-value 0.18 w/m2k, floor 0.13 w/m2k, roof 0.11 w/m2k,• Air tightness of 5 m3/m2/hr @ 50 Pa,• Mains Gas boiler, • WWHRS,• Photovoltaic Panels

• An average increase to build cost of £4,600 per plot.

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3 Targets explained

• Its driven by fuel choice• Carbon (kg CO2 /kWh)• Price (p/kWh)• Primary Energy (kWh/m2/yr)

• The fuels are not always good on all three!

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Householder Affordability Rating

• Move towards electric heating, an expensive fuel.

• A minimum EPC rating for all new dwellings is proposed. (number or band?)

• BEIS statistics show 81% of all new build EPCs are ‘B’ rated.

• 1.34% of EPCs are ‘A’ rated

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Some Example Homes

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Modelling

• A house which complies to current L1A 2013 regulations• Will not comply

DPER TPER1 TPER2 DER TER1 TER2 EPC

Detached House

Gas 79.84 56.97 53.29 13.33 10.24 8.51 84 B?

Oil 79.95 56.97 53.29 17.73 10.24 8.51 88 B?

LPG 79.62 56.97 53.29 14.94 10.24 8.51 80 C?

Electric 63.4 56.97 53.29 6.13 10.24 8.51 71 C?

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Modelling – Gas

• To achieve compliance with option 1 (20%) typically;• Improved fabric u-values – wall 0.18 w/m2k, roof & floor

0.11 w/m2k• Used triple glazing• Introduced WWHRS• Lowered psi values• 1.3 kWp PV

DPER TPER1 DER TER1 EPC

56.85 56.97 9.72 10.24 91 B

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Modelling – Gas

• To achieve compliance with option 2 (31%) typically;• Changed ventilation to MVHR • Lowered airtightness to 3 m3/m2/hr @ 50 Pa

DPER TPER2 DER TER2 EPC

45.21 53.29 7.26 8.51 92 A

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Modelling – Electric Heat Pump

• To achieve compliance with option 1 (20%) typically;• Retained fabric u-values – wall 0.22 w/m2k, Roof & Floor –

0.12 w/m2k • Retained double glazing,• Improved lighting to 80 l/cw

DPER TPER1 DER TER1 EPC

56.76 56.97 5.49 10.24 74 C?

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Modelling – Electric

• To achieve compliance with option 2 (31%) typically;• Improved psi values• Still no renewables or WWHRS• BUT keep an eye on EPC score

DPER TPER2 DER TER2 EPC

48.92 53.29 4.72 8.51 78 C?

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Other Proposals

• Standard compliance report• Photographs to verify on site construction, ‘signed off’

by OCDEA and developer prior to going to building control. (Provided to homeowners)

• Transitionals• What is a ‘reasonable’ time?• Per plot not site!

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Conclusions• Homes will be more ‘energy efficient’ – journey towards Future Homes Standard

• New compliance metrics are a balance of primary energy, carbon and cost. (with backstops!)

• Airtightness testing to increase.

• Steps being taken to address the performance gap and provide more information to the householder.

• Removing LA’s ability to set standards above!

• Transitional arrangements to ensure new dwellings are built to latest standards.

• Use of Competent People

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When?England:• Consultation (deadline 7th Feb 2020)

• Publish new Regs Spring 2020*

• Implement Autumn 2020*

Wales:• Similar timelines to England* (propose 37% or 56% uplift)

• Consultation (out now, deadline 12th March 2020)

Scotland:

• Changes & Information published in Oct 2020*

• Guidance and Standards introduced in Oct 2021*

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Consultations coming soon

Should you respond?

Part L2 • Non domestic (new build) L2a• Non domestic (existing buildings) L2b• SBEM

Part L1b • Existing Homes, conversion and extensions

Overheating• More details to where it may sit in regulations

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www.elmhurstenergy.co.uk