High Performance Building Envelope Design to Achieve PassivHaus Standards

Transcription

1 High Performance Building Envelope Design to Achieve PassivHaus Standards BRYAN WOODLEY MANAGING DIRECTOR VAL-U-THERM LIMITED Topics Covered Myths & Reality of PassivHaus Costs & Economics Concepts Design Performance Matching to Client Aspirations 4 Practical Design Criteria Based on > 4,500 homes Practical Solutions Affordable Sector Case Studies 1

2 Concepts 1. Highly mathematical & technical 2. Minimise surface area for a given living space 3. Desperately expensive with no payback PassivHaus Myths Dose of Reality 2

3 1. Highly mathematical & technical NO PassivHaus Planning Package PHPP straightforward Excel spreadsheet University of Darmstadt, PassivHaus Institut, are to be congratulated PassivHaus Reality Dealing with Myths PHPP is True Design Tool Better than SAP pro-active Envisage changes calculate the effect PUTS COMPLETE FABRIC FIRST 2. Minimisesurface area for a given living space Laws of Physics: live in a sphere Form Factor: cube is close to a sphere PassivHaus NOT Serried Ranks of Boring Boxes facing South PassivHaus Reality Dealing with Myths 3

4 3. Desperately expensive with no payback NO UK just starts from a bad position British houses are notoriously energy inefficient PassivHaus Reality Dealing with Myths Obscene that people die of hypothermia in their homes in 21 st century Wouldn t buy a car without asking mpg Why build a house without asking the same question? FINANCE DRIVES REALITY Independent Research into Space Heating University of Strathclyde Software by C4Ci 60 s 70 s 80 s 90 s 00 s Val-U- Therm 4

5 Low Heating Bills University of Strathclyde Software by C4Ci Space Heating Costs /yr Building Regs As Built (JRF) Building Regs Minimum (Part L) Val-U-Therm Medium Spec Val-U-Therm High Spec Cumulative heating bill saving ( k) Fuel Cost Inflation 25, s 1980s 20, s 2000s 15,000 10,000 5, In our personal budgets Government statistics between 2004 & 2014: Average domestic UK electricity bills increased by 100% Average domestic UK gas bills increased by > 110% by C4Ci Timescale 5

6 Savings by Moving to a New Home 20k - 25kover next 15 years Typical detached home 4 bed, 3 reception, 2 bath Integral garage PassivHaus design allows: Warm, draught proof, comfortable homes in winter Cool & well ventilated homes in summer Remarkably low energy bills PassivHaus Reality Dealing with Myths SUIT: YOU (OR YOUR CLIENT) YOUR LIFESTYLE ASPIRATIONS 6

7 Design Performance specification Not prescriptive about: How to do it Products used Legal compliance Does allow for: Heat loss through roofs, 25% Through outside walls, 35% PassivHaus Overview Through ground floors, 15% Through doors & windows, 25% Allows for thermal bridging 30% For heat loss through air leaks 30 % 7

8 1. Optimisethe building s form and orientation 2. Super insulation Four Practical PassivHaus Criteria KISS 3. MVHR (mechanical ventilation & heat recovery) 4. Maximum primary heat demand To reduce heat losses To maximisesolar gain (active & passive) Choice of building plot 1. Building Form & Orientation Can be a showstopper Use of building plot Shading from trees, etc. Early project involvement Check feasibility 8

9 Integrated approach to building envelope 2. Super Insulation Fabric First Approach Excellent fabric thermal insulation: U-value Theoretically up to 0.15 W/m 2 K In practice Val-U-Therm at 0.09 W/m 2 K Enables some flexibility of design when meeting PassivHaus criteria Minimal thermal bridging ( negligible ) Ψ-factors and Y-values Enhanced construction detailing to Y-value < 0.05 W/m 2 K In practice, Val-U-Therm to Y-value 0.03 & Ψ- values of or better Air tightness < 0.6 ACH In practice, Val-U-Therm regularly at ACH, even 0.46 ACH at 50 kpa 3. MVHR Mechanical Ventilation & Heat Recovery PassivHaus requires > 75% efficiency Deceptively simple SAP Appendix Q testing methodology Cost of PassivHaus certification Choice: A) Purchase certified product pay a premium B) Purchase non-certified (and usually perfectly good) equipment & suffer a 12% penalty applied to the efficiency in the PHPP calculation Increasingly leads to building to PassivHaus Principles rather than Certification MVHR must do what it says on the tin 9

10 Specific Heating Demand 15 kwh/(m2.a) Specific Cooling Demand 15 kwh/(m2.a) Specific Heating Load 10 W/m2 4. Maximum primary energy demand Specific Primary Energy Demand 120 kwh/(m2.a) Air Changes Per Hour n50 The text book bit Advanced Closed Panel System Latest innovations in off-site construction Launched 1st June 2011 Already built over 4,500 homes All types & sizes Integrated system: walls, roofs & flo0rs 4 factories involved in manufacture 14 sales offices in UK - 0verseas Not just for housing Val-U-Therm 10

11 A hybrid eco closed-panel timber system How is This Achieved in Practice? Val-U-Therm Building Solution Best of both SIPS & Timber Frame Exceptional thermal insulation performance Class-leading environmental sustainability credentials recycled renewable vegetable oil Delivered flat-pack configuration with factory fitted windows & doors BBA third party accredited for 60-year minimum service life In a cost-effective package Demonstration of Factory Injected Val-U-Therm Insulation On valutherm.co.uk & YouTube 11

12 Case Studies First PassivHaus for rent in the UK Client: Kingdom Housing Association Builder: Campion Homes Manufacturer: Scotframe Location: Pittenweem, Fife 1. Kingdom House 5 person two storey detached family home 104m2 including 4.5m2 of storage Scottish Government funding 12

13 Kingdom House Design Specification Val-U-Therm external wall panels: 0.09 W/m 2 K Val-U-Therm roof panels: 0.09 W/m 2 K Insulated concrete ground floor: 0.12 W/m 2 K With factory fitted windows & doors Nordan N Tech Passiv 0.8 W/m 2 K Negligible thermal bridging Air tightness < 0.6 h -1 INTEGRATED BUILDING SYSTEM Kingdom House: Wind and Weather Tight PassivHaus Construction in One Day 13

14 PH Min Standards Actual Space heating demand kwh/m 2 per annum Primary Energy Demand kwh/m Air Change Rate (h -1 ) MVHR Efficiency 75% 90% Performance in Practice Green Apple Award for Scotland 2011 SG Independently Audited Standard KHA Spec PassivHaus with no Renewables PassivHaus with Renewables Energy Efficiency Rating B (83) B (87) A (98) EnvironmentalImpact (CO2) Rating B (82) B (88) A (101) Energy Use kwh/m 2 pa Estimated Fuel Costs pa CO2 Emissions Tpa Comparison Study SG Independently Audited Energy Consumption reduction of over 88% Carbon neutral 14

15 5 P E R S O N T W O S TO R E Y D E TA C H E D FA M I LY H O M E O F M 2 TOTA L F U E L C O S T S 9 1 / Y E A R G OV E R N M E N T A U D I T E D Val-U-Therm can allow a typical family to have a home that costs less than 95 per year to heat 27 new build homes 10 different system builds used to demonstrate MMC s including Scotframe Val-U-Therm Only 1 PassivHaus on site Val-U-Therm selected 2. Dunlin Drive, Dunfermline Housing Innovation Showcase 15

16 Dunlin Drive: Construction Cost & Time 27 new build homes Cost per m 2 of superstructure ( ) Range from 711 to 1138 (built to existing Building Regulations) Val-U-Therm to PassivHaus standards at 1092 Construction period (days) Superstructure only 27 homes range from from49 to126 days Val-U-Therm took 65 days (PassivHaus standards) Dunlin Drive: PassivHaus Design vs As-built Independently audited by Edinburgh Napier University Audit team noted that Val-U-Therm is highly flexible in meeting design fabric efficiency Little detailing & adaption needed to meet thermal & airtight efficiency AirPermeability m 3 /(h.m 2 50Pa Design As-built SAP Rating 85B 85B EI(CO2) Rating 88B 88B Dwelling Emission Rate DER (Kg/yr) Total Primary (kwh/m2/yr) Total Energy Use (kwh/year)

17 Dunlin Drive: PassivHaus Design vs As-built Costs Smart Metering + MVHR No low carbon technology installed Independent Audit: Energy Cost ( /year) Design As-built Space heating Water heating Lighting Pumps & fans TOTAL MVHR system claimed 93% efficient; field tests showed only 85% efficient German PassivHaus Institut accredited system; MVHR uses 153kWh Filters inspected some dust accumulation but generally sufficiently well maintained Hot water tested at one minute intervals: average temperature above 48 Energy efficient light bulbs > 75% (to fulfill SAP) but not 100% Dunlin Drive: Tenant Satisfaction 10/10 for all aspects Excellent thermal performance Much training re MVHR The fact that they lived in a property designed to PassivHaus standard made them feel special and this helped them think about saving energy. This system also scored 10/10 for all aspects of personal control over heating, lighting, ventilation and noise, reflecting very high levels of satisfaction. Importantly, the residents believed that the quality of air in their home was better and positively affecting their health: you get constant fresh air so you are bound to feel healthier! ; My son used to suffer from a blocked nose but now -it is totally opposite! 17

18 3. emh in Derbyshire Lindum Group 9 affordable homes All built to an equivalent specification 3 properties receiving the formal PassivHaus accreditation Client perspective: poor integration of low carbon technologies; high maintenance issues; dwellings not performing as expected and homes having higher bills than predicted PassivHaus inspired fabric first approach Client Perspective emh Compared against commonly adopted and high-tech approaches: low carbon technologies ground and air source heat pumps bolt on renewables solar PV and solar thermal Whole life costs and benefits evaluated Demonstrate lifetime performance Key deciding factor for RPs Long term vested interest in their building stock 18

19 Encraft PassivHaus consultants Used the Val-U-Therm wall system with a U-value of 0.09W/m 2 K Actual air testing results across the site ranging from 0.46h -1 to 0.58h -1 at 50Pa -all plots achieved PassivHaus standards Enhanced construction detailing to achieve a SAP y-value <0.05W/m 2 K emh Key facts Total cost of the build just under 1,400 per m 2 Finalist in the Cost & Buildability Category for the UK PassivHaus Awards 2014 PASSIVHAUS IS AFFORDABLE emh: Tenant Satisfaction Philip Haines -Resident noted, I just can t praise it enough, so much different to our old house, never go back to the original old sort of houses, these are absolutely superb. Miss Raines, one of Hart Lea s first residents, is delighted with her new home. She said: I couldn t have asked for a better house. I am so happy. Janette Donson-Resident noted, Energy-wise we have cut the bills to under half can t hear the road that s close by. 19

20 Conclusions PassivHaus is straightforward PassivHaus is deliverable in UK Superb energy efficient homes Reflect lifestyle & aspirations Healthy, flexible accommodation Warm & draught-free in winter Cool & comfortable in summer Future-Proof re codes & regulations Private developers: kerb appeal PassivHaus is NOT JUST for one-offs & up-market homes ALSO HIGHLY AFFORDABLE RP s & Charities Integrated building system No bolt-on goodies to give thermal performance & air tightness Fully accredited & tested Timber is an excellent basis to use Conclusions GIVE A FINANCIAL PAYBACK Whole life cost savings & benefits 20

21 THANK YOU FOR YOUR TIME QUESTIONS & COMMENTS PLEASE BRYAN WOODLEY VAL-U-THERM LIMITED valutherm.co.uk, flighttimber.uk, scotframetimberengineering.co.uk & walkertimbergroup.com 21