Implications of Energy Performance Certificates on designing and managing office buildings

1
Implications of Energy Performance Certificates
on designing and managing office buildings

• Tony Johnson
• Principal Consultant, Sustainable Energy
• BRE

2
Content

• Statutory requirements
• EPBD
• CLG
• Display Energy Certificates
• Scope Basis of calculation A-G rating
• Advisory report
• Energy Performance Certificates
• Basis of calculation Reference values A-G
  rating
• Recommendations report
• Implications for design and management
• Measures Calculating benefit

3
Statutory requirements
4
EU Energy Performance of Buildings
Directive(EPBD)

• Requires Member States to introduce by end 2005
• Minimum Energy Performance Standards (New
  buildings)
• An acceptable methodology for calculating the
  integrated energy performance of buildings
• Minimum energy performance standards for new
  buildings
• Minimum energy performance requirements for large
  existing buildings subject
  to major renovation
• Energy performance certificates (Existing
  buildings)
• Provided to prospective purchaser/tenant
• Prominent display of the energy certificate in
  all public
• buildings and institutions providing public
  services
• Regular inspection associated with
• Boilers
• Air-conditioning systems
• Calculations carried out in an independent
  manner, by qualified and/or accredited experts

5
CLG requirements -What is a building?
a roofed construction having walls, for which
energy is used to condition the indoor
climate a building may refer to the building as
a whole or parts thereof that have been designed
or altered to be used separately
6
CLG requirements Building Regulations Part L

• To implement EPBD Articles 3 6
• Move to a whole building approach based on carbon
  targets
• Minimum performance to be set using SAP or SBEM
• No longer reliant on the elemental approach
• More attention to be paid to summer performance
• Stronger encouragement for Low and Zero Carbon
  systems
• Extends coverage of measures installed in
  existing buildings
• Firmer requirements for pre-completion testing
  and log books
• More self certification
• Came into force 6 April 2006

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Structure of Part L

• ADL1A new dwellings
• ADL1B work in existing dwellings
• ADL2A new buildings that are not dwellings
• ADL2B work in existing buildings that are not
  dwellings

8
CLG requirements EPCs, DECs and Inspections

• Provide EPC on construction, sale or rent
• Also recommended at design stage
• Must show asset rating
• ie numerical indicator of energy performance of
  building fabric and services associated with
  standardised use of building
• Expressed on A-G scale
• Must not be more than ten years old
• Only few exceptions
• Places of worship temporary buildings (2 yrs or
  less) less than 50sqm
• Provide recommendations for improvement
• Display energy certificates for public buildings
• ie comparison of metered energy consumption with
  benchmarks
• Inspection of air conditioning systems
• boilers covered by other advice (Information
  campaign)

9
CLG requirements timescale

• EPCs are required on sale or let for
• New buildings - 6 April 2008
• Existing buildings depend on building size
• gt10000 m2 - 6 April 2008
• gt2500 m2 - 1 July 2008
• gt50 m2 - 1 October 2008
• Not required for property coming onto market
  before size deadline, but will be needed by 1
  October 2008
• Display Energy Certificates required annually for
  all public buildings gt1000m2 from 1 October 2008
• Air conditioning system inspections required for
  new systems within 5 years Existing systems
  gt250kW by 4 January 2009, gt12kW by 4 January 2011

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Which certificate when?

• At the point of construction, sale or rent
• Dwellings and (almost) all other buildings
• Asset Rating - Energy Performance Certificate
  (EPC)
• Which building should I occupy?
• Compare assets on a consistent basis
• Calculation on a standardised basis
• How might that building be improved?
• Public display
• Initially large public buildings visited by the
  public
• Operational Rating - Display Energy Certificate
  (DEC)
• How good is this building and how well is it
  being operated?
• How can it be improved?
• Management and operation / Fabric and plant

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Inspection of boilers and air conditioning

• Air conditioning systems
• Inspection and report necessary
• Valid for max 5 years
• All systems gt 12 kW output
• Initiated by relevant person who has control of
  system operation
• Can be done in-house provided individuals have
  appropriate training and accreditation
• Content based on CIBSE TM44

• Boilers
• England Wales taking advice option
• Deemed to be provided by recommendations attached
  to EPC and DEC
• So no army of inspectors!

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Operational Rating Display Energy Certificate
13
Operational Ratings - non domestic, public
buildings

• Based on measured in-use consumption data
• Includes intrinsic performance, plus effect of
• Actual plant performance
• Actual occupancy, location, etc
• Actual management practices by occupants at the
  time
• A comparative rating with respect to benchmarks
• Some normalisation for weather and occupancy
• Used to establish scope for improvement
• Must recommend improvement measures
• No theoretical calculation required

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DEC Scope

• SI 991 Reg. 16 (1)
• Applies to buildings with a total useful floor
  area over 1,000m2
• occupied by public authorities
• and by institutions providing public services to
  a large number of persons
• and therefore frequently visited by those
  persons.

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Central Information Point (CIP)

• Software specification
• Operational Rating / DEC information
• Postcode to Weather Region
• Monthly degree days
• CO2 intensities of fuels (kgCO2/kWh)
• Approved Benchmark Information
• Building types and benchmark categories
• Electrical and non-electrical energy densities
  (kWh/m2/yr)
• Separable use options
• Standard degree days
• Adjustment factors
• Approved template for DEC

16
DEC Basis of calculation

• Operational Rating (metered CO2 / TUFA ) x 100
• (benchmark CO2 / m2)
• 95 of fuels must be metered
• Align DEC assessment period with Main Heating
  Fuel
• Synchronise other fuels measuring period
• Corrections allowed for metered
• Allowed separable energy uses
• Low and zero carbon inputs
• Exports

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DEC Basis of calculation

• Operational Rating (metered CO2 / TUFA ) x 100
• (benchmark CO2 / m2)
• Benchmarks are obtained from Central Information
  Point (CIP) - based on CIBSE benchmarks
• Converted to CO2
• Corrected for heating degree days
• Corrected for occupancy
• Where building has multiple activities and
  metering only available at whole building level,
  use area weighted benchmark

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DEC bands
Typical lower limit of D

• Failure to provide adequate information gives
  default OR 200 ie G worse rating

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DEC data entry
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DEC design

• A-G rating
• Current
• Carbon emissions
• Current
• Previous
• Operational rating
• Current
• Previous
• Administrative information

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Full Technical Table

• Annual energy use, CO2 emissions Units for
• and performance indicators Fuel and
  heat Electricity energy data CO2 emissions Units
  for CO2 data
• Total energy use in the year concerned 100,000 230
  ,000 kWh 146.5 tonnes CO2
• Separable energy use deducted 1 (if
  any) 5,000 150,000 kWh 83.5 tonnes CO2
• Separable energy use deducted 2 (if
  any) 0 0 kWh 0 tonnes CO2
• Calculated performance indicators 95 80 kWh/m2
  pa 63 kg CO2/m2 pa
• Reference performance benchmarks
  corrected 160 100 kWh/m2 pa 87 kg CO2/m2 pa
• Benchmark ratios and Operational
  Rating 59 80 Typical 100 72 Typical 100
• Operational Rating grade (A is best) Not
  applicable Not applicable Not applicable C A to G
•             Units for age kWh
• Displaced energy Fuel and heat Electricity energy
  data displaced Units
• Fossil Fuel Energy Displaced 5,000   kWh 5 of
  total
• Grid Electrical Energy Displaced   16,000 kWh 7
  of total
• Building types Area (m2)
• Office 1050
• Benchmark category 2  
• Benchmark category 3  
• Benchmark category 4  

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DEC Advisory report method

• Gather information from
• Building walk-around Previous knowledge
• Competent third party Existing valid reports
• eg EPC RR, AC inspection, LCC, etc.
• Software includes standard measures database
• Series of questions filter out irrelevant
  measures
• Assessor provides final check inputs own
  measures

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DEC Advisory report contents

• Measures to improve building energy efficiency
• Short-term payback (0-3yrs)
• eg energy management
• Medium-term payback (3-7yrs)
• eg upgrading services
• Long-term payback (gt7yrs)
• eg LZC technologies
• Advisory report for information only.

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Sample Advisory Report
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Asset Rating Energy Performance Certificate
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Asset Rating for EPC

• The calculated intrinsic performance of the
  building as built
• Normalised to standard conditions (weather,
  occupancy)
• Recognises different activities (temperatures,
  occupation times)
• Applicable to both new and existing buildings
• Automatically compares with a Reference
  Building as the baseline
• Generates a comparative rating (A-G and numeric
  ratio)
• Allows comparison between similar buildings on
  level playing field
• Compatible with compliance checking before
  building is built
• Produces recommendations for improvement

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EPC Basis of calculation
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Basis of calculation

• National Calculation methodology (NCM)
• ie SBEM or approved alternative software
• Looks at heating/cooling needs of every zone,
  then system needs via efficiency hot water and
  lighting similar - a lot of input data!
• Standardised use rather than actual operating
  pattern
• To allow buildings with different actual usage
  patterns to be compared
• Comparison with a number of different buildings
• Notional (2002), Reference (2002), Typical of
  existing stock (1995)
• Improvement factors to upgrade to current
  standards
• When regulations change, improvement factors will
  be updated
• Being based on comparison reduces impact of
• survey error, modelling assumptions (zoning etc)

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Basis of calculation

• Notional building
• Same size and shape as actual building (but
  glazing area depends on activity)
• 2002 insulation standards
• Same HVAC strategy but with 2002 system type
• Each space contains same activity (and therefore
  activity schedules including set point
  temperatures and other parameters) as actual
  space
• Same orientation and weather
• Detailed definitions given in NCM Modelling Guide
  (to be published soon)
• Improvement factor to bring up to current
  standards (2006)
• Depends on HVAC strategy (ie greater improvement
  for mech vent or cooled)
• Low/zero carbon benchmark
• Notional with improvements Target Emission Rate
  (TER)
• Newly built benchmark

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Basis of calculation

• Reference building is same as notional building
  but with
• Gas heating
• Seasonal mixed mode cooling when temperature
  exceeds 27oC
• Cooling only counted when needed to avoid
  overheating
• Same regardless of HVAC system in actual building
• Improvement factor to bring up to current
  standards (2006)
• Same regardless of HVAC strategy
• Includes Low/zero carbon benchmark
• Reference with improvement Standard Emission
  Rate (SER)

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Basis of calculation

• Typical building is same as notional building but
  with
• 1995 standard insulation etc
• 1995 standard HVAC systems
• Gives Typical of existing stock benchmark
• Actual building carbon
• calculated with the same calculation engine
• Generates the Building Emission Rate (BER)

35
Basis of calculation

• Comparison with Reference Building improved by
  fixed factor (23.5) - ie Standard Emission
  Rate
• Rating calculated as ratio BER/SER carbon x 50
• So 50 represents a building to current standards
• Converted into a rating band (A-G) but numerical
  rating too
• EPC includes reference values -

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Reference values

• Zero carbon
• Standard Emissions Rate
• Reference building with improvements
• Comparison with a new version of the same
  building
• If newly built
• Current Part L legal standard
• Compliant allowing for chosen HVAC strategy
• If typical of existing stock
• 1995 fabric and plant
• How good is this building relative to the stock?

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Reference values

• Zero carbon
• Top of band A
• Standard Emissions Rate
• B/C boundary
• Score 50
• If newly built
• Benchmark
• If typical of existing stock
• Benchmark
• D/E boundary
• Score 100
• Not necessarily typical
• To align with DEC

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Compare with DEC
39

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Recommendations Report
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Recommendations Report

• Offers suggested measures for improving the
  intrinsic asset
• Selected from a generic list of measures
• similar list as for DEC Advisory Report
• Filtered using
• Data input to calculation
• Results from calculation
• Additional information from assessor
• Then to be reviewed by assessor to subtract, add
  or comment on measures

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Implications on design of offices - and
improvements
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Buildings can be more efficient

• New buildings should take Building Regulations as
  a minimum standard
• Not the target to aim at
• Better performance is perfectly possible and need
  cost little or no more to build
• Major refurbishment offers a golden opportunity
  to improve performance too
• The benefits are significant how can they be
  achieved?

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The whole-system approach to design

• Site considerations
• Location and weather
• Microclimate
• Site layout
• Orientation

Integrating the design process Normally all
the really important mistakes are made on the
first day of the design process! - Amory Lovins

• Built form
• Shape
• Thermal response
• Insulation
• Windows/glazing

Daylighting strategy
Ventilation strategy

• Services strategy
• Plant and controls
• Fuels
• Metering

Source CIBSE Energy Efficiency in Buildings
Guide
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Where the savings come from

• Reducing demand for artificial heat, ventilation,
  cooling and light
• Orientation
• Layout
• Thermal responsiveness
• Daylight
• Natural ventilation
• Improve the efficiency of meeting that demand
• More efficient plant
• Optimum sizing
• Appropriate controls

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Design example - Daylighting

• Window design and building design has a direct
  effect on
• need for solar control and/or air conditioning
• size and capacity and space required for central
  plant
• air and water distribution system
• artificial lighting design

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Natural ventilation

• Three key issues
• building tightness (build tight - ventilate
  right)
• good ventilation for occupants
• natural ventilation design

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Natural ventilation example- The Environmental
Building, BRE

• Stop excessive solar gain through windows
• Minimise warming of the walls by the sun
• Minimise heat produced in the building
• Cooling by natural ventilation
• use of thermal mass
• night ventilation cooling

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But what about existing buildings?
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Implications of improvements using SBEM

• An existing 20 year old (anonymous) building
• Not bad, compared to typical
• What could be done with it?

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SBEM diagnostic options
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Example Output report

• Total consumption
• 236 kWh/m2/yr
• Heating dominates delivered energy
• Cooling and lighting could be improved to reduce
  carbon emissions

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Example Recommendations Report
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Impact of selected measures

• Improve cooling efficiency
• New chiller
• Change life expired fan coils to chilled beams
• Improve heating efficiency
• New condensing boiler
• Optimum start, weather compensation and local
  temperature controls
• Improve insulation
• Double glazing
• Walls and roof
• Upgrade lighting controls
• Daylight sensing
• Occupancy sensors in meeting rooms and toilets

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Improved office
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New EPC

• Now C rating
• Closer to current standards

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Revised performance

• Total consumption reduced by 70kWh/m2
• Heating still dominates, but not as much
• Cooling reduced by 40
• Lighting reduced by 14
• Carbon down by 30

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Implications on management of offices
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Can you anticipate impact of improvements on DECs?

• You could implement advisory report measures on
  the actual building
• But what would be the change in consumption?
• DEC reflects actual measured performance
• Could estimate change and recalculate
• Eg use SBEM to estimate lighting energy
  difference if better controls
• But this would not be an official rating
• Proof of the pudding is in the metering
• Next time around!

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Summary
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So what are the benefits?

• New and refurbished buildings
• Raise standards across the board
• Level playing field for comparison - see what you
  are getting
• Avoid architectural greenwash - exaggerated
  claims
• Check on quality of buildings offered by PFI
  contractors
• Aligns with public opinion on mitigating climate
  change
• Low carbon is often more occupant-friendly
• Lower energy costs

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So what are the benefits?

• Existing buildings
• Asset rating allows comparison between buildings
  offered to you on consistent basis
• Manage portfolio - rent renegotiation, dispose of
  poor buildings?
• Operational rating checks whether buildings are
  intrinsically poor or just badly managed
• Proven environmental credentials help staff
  retention
• Proven environmental credentials help public
  relations

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Remember

• Regulations and certification are not there as a
  burden - they are vital drivers towards lower
  carbon buildings through
• Informing your decisions about choosing between
  building options
• Ensuring consistency
• Avoiding inadequate design and shoddy workmanship
• Helping you to get a building which is easier and
  cheaper to run, with productive occupants
• Potentially increased value
• Helping you to show all stakeholders that you
  care about your buildings impact on the
  environment
• Everyone wins including the environment

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References

• Building Regulations and Approved documents
• http//www.planningportal.gov.uk/england/professio
  nals/en/4000000000562.html
• Questions on EPC rules interpretation - CLG
  guide Improving the energy efficiency of our
  buildings http//www.communities.gov.uk/publicati
  ons/planningandbuilding/guidancenondwellings
• Information on EPC, DEC Inspections
• Statutory Instrument http//www.opsi.gov.uk/si/s
  i2007/uksi_20070991_en.pdf (as amended 1669,
  3302, 647)
• CLG Circular http//www.communities.gov.uk/publi
  cations/planningandbuilding/circularenergy
• SBEM User Guide Technical manual, NCM
  databases
• Go to http//www.ncm.bre.co.uk for download