Building PassivHaus Communicating the Challenge

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1 The Bristol Green Capital Partnership PassivHaus Conference How can we build greener and better buildings? The case for PassivHaus development Building PassivHaus Communicating the Challenge Colin Powell BA(Hons) DipArch Msc RIBA :

2 Introduction Effective sustainable design requires a detailed knowledge of building science, technology and construction Our core skills as architects provide our clients with a depth of understanding that informs our advice on energy and sustainability Our consulting business provides the specialised knowledge of sustainable and low energy design needed to help our clients achieve their ambitions

3 Communicating the challenge Feedback Review Performance in-use Learning CLIENT Brief User group Management Budget Marketing BUILDING USER DESIGN TEAM Quality control Testing Commissioning Recording BUILDER (site) BUILDER (tender) Performance Specification Details Products Testing Management Program Sequencing Subcontractors Trades

4 Design Decisions understanding the issues Being comfortable in buildings requires energy, for heating, lighting, hot water and appliances To design low energy buildings the first thing we need to understand is where the all energy goes Its all a matter of balance!

5 Design Decisions understanding the issues Understanding where energy goes is a key part of optimising design PassivHaus enables informed design After internal & solar gains this model needs 74 kw/m 2 Heating to balance energy loss 47% 3% Proportional losses 4% energy loss 101 kwh/m 2 /yr 13% 24% 9% Floor Wall Roof Windows Ventilation Therm.Bridge Proportion of energy lost through elements Building Regs

6 Design Decisions understanding the issues Understanding where energy goes is a key part of optimising design PassivHaus enables informed design After internal & solar gains this model needs 14 kw/m 2 Heating to balance energy loss 38% 16% 0% Proportional losses 9% energy loss 36 kwh/m 2 /yr 14% 23% Floor Wall Roof Windows Ventilation Therm.Bridge Proportion of energy lost through elements PassivHaus

7 Design Decisions developing a strategy Start with a simple strategy Complexity is not your friend! A simpler strategy will be easier to deliver

8 Design Decisions developing a strategy Think about the space implications at design stage it is difficult to create spaces for services later on Ensure the team understand why spaces are there and what they are for

9 Tendering performance spec Communicating critical issues Performance specification needs to be embedded from the outset Standardisation and variations one size will not fit all! Responding to site specific issues how is this identified and recorded

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11 Tendering ensuring everything is included Tender information needs to be clear on factors that will affect trades and specialist suppliers PassivHaus details may affect sequence of works and this needs to be understood at tendering Beware of value engineering!

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13 Construction understanding the priorities Engaging with site team and trades Toolbox talks and presentation to key trades Share objectives and reasons why the project is different Emphasis on detail, change control and responsibility for workmanship

14 Construction understanding the priorities Engaging with site team and trades Toolbox talks and presentation to key trades Thermal bypass can reduce the effectiveness of insulation by as much as 70% Share objectives and reasons why the project is different Emphasis on detail, change control and responsibility for workmanship

15 Construction understanding the priorities Check details for buildability, test details to ensure they work

16 Construction controlling the works Continuity between tender and contract team

17 Construction controlling the works Attention to detail

18 Construction controlling the works Sequence of work and controlling trades Interior space enclosed in a continuous barrier to reduce uncontrolled ventilation Materials and methods of construction and jointing Position and protection Junctions and sealing Site control to achieve continuity and avoid damage

19 the construction challenge Testing testing testing! Test early whilst the problem can still be fixed Establish a system of control for following trades

20 Consider alternatives ICF construction Fast and easy to build Highly insulated First air test 0.45 AC/H

21 Engaging the user Success of the project will rely on a good briefing for the end-user Heating by towel rails press boost if you need some extra warmth The boiler is small and won t be running very much don t worry it s not broken! PassivHaus needs to be driven and will take time to acclimatise - the user and the building Explaining the reason for controls is as important as knowing what they do Understanding seasonal variations will ensure comfort in different conditions On hot summer days keep the windows closed! Open windows in the evening for cooling Keep the ventilation on auto and press boost if things get steamy

22 : delivering effective low-energy buildings Collaborative Supportive Creative Pragmatic Professional thank you : colin.powell@arch.co.uk