What is Passivhaus?

byPiers Sadler

EnerPHit

EnerPHit

Passivhaus Criteria

Air-tightness 0.6ACH @ 50Pa1 ACH EnerPHit

Comfort

Surface temperature (windows)

>17oC Comfort

Summer over-heating Max 10% >25oC Comfort

Ventilation 30m3/hr/person ComfortHeating 15 kWh/m2/yr EnergyPrimary Energy 120 kWh/m2/yr Energy

Fabric first is embedded in these criteria

Passivhaus Criteria

• Whole building warm• No draughts• No cold radiant surfaces• Fresh air always• No summer over-heating• Heating bills ~£60/yr

Five Basic Principles

Comparison with UK Part L1A, 2013

Comparison with UK Part L1A, 2013ItemU values in W/m2K

Building Regs(typical)

Passivhaus(upper limit)

Walls U value 0.180.15

Roof/floor U value 0.13Windows U value 1.4

0.8Doors U value 1.0-1.2Airtightness 5m3/m2/hr 0.6 ACHThermal bridging moderate thermal bridge freeVentilation natural heat recoveryFabric energy efficiency(kWh/m2/yr) ~45-60 15

Building Form

Source: AECB Carbonlite, Passivhaus Designer Course

Common Misconceptions

You can’t open the windows

Sealed buildings are unhealthy

Mechanical ventilation is energy intensive/expensive

Heating is not required✗✗✗✗

Passivhaus Planning Package (PHPP)

Certification/Quality Control

PHPPDetail drawingsSupplementary modelling (thermal bridging)PhotographsAir test

Design & Construction Certification CompletionDesign Team

Performance Gap

Passivhaus

Source: Leeds Beckett University

Performance Gap

Source: Passivhaus Institute

Whole Life Costs (NPV)

Passivhaus NPV was always less than the typical house

Benefits

Passivhaus build by Keepmoat, OldhamSource: The Guardian

• Eliminates fuel poverty

• Low and predictable CO2 emissions

• High levels of thermal comfort

• Good indoor air quality

• Health dividend

So:What is Passivhaus?

• First rate thermal comfort• Exceptional energy performance• Excellent air quality• Delivers on design intent

Thank you

www.piers-sadler.co.uk