Learnings from residential PH design and procurement in Australia. Luc Plowman

Transcription

1 Learnings from residential PH design and procurement in Australia Luc Plowman

2 Summary Stakeholder education Expectations Materials & documentation Heating & cooling Costs Documentation requirements The certification process What have we learned?

3 Sustainability Consulting What does Detail Green do? Collaborations with architects / designers / builders PH experience to date - residential buildings PH projects Sustainable Building Design and AMBE Engineering, plus many other clients who want a building close to the PH standard

4 Stakeholders Clients Everyone likes the idea of a PH! Architects / designers / engineers Mostly client driven Builders Is there sufficient information to price & build? Do they like doing different projects? Image courtesy Sustainable Building Design

5 Stakeholder education What to expect? The PHPP is a rigorous toolkit but needs to be used carefully. PH is a tried and tested product Differences to local requirements Strict requirements Far more accurate modelling of thermal performance and comfort Thermal bridges must be eliminated & building must be airtight! A different approach! PH are simple buildings don t need all the green add-ons To achieve the most for money, the floor plan needs to be as efficient as every other aspect of the design. Plans can vary as much as 30% in the amount of non-habitable space, which can equal tens of thousands of $$

6 Expectation management The process takes time both design and construction (detailed design planning required, 3 rd party Q.A., detailed construction techniques) Quality assurance provided with PH (thermal comfort, maximum energy efficiency, indoor air quality) Design process & interactions with certifiers (careful consideration of building design, in particular building envelope will dictate performance and cost effectiveness) Image courtesy Sustainable Building Design

7 Case Study Steel s Ck Design >12 months including liaison with PHI certifiers Working through how to enter a split system in to the PHPP accurately Thermal bridge modelling Difficulty obtaining comparable HRV quotations provisional sum Delivery of HRV timing Windows bushfire requirements and air tightness Construction period 12 months

8 Windows Local products vs Imports Air tightness cost ~$1000/m2 Insulated concrete slabs Engineering cost Air tightness membranes Where does it go? HRV systems External Doors Insulation products Solar PV Materials Thermal mass is generally seen as particularly beneficial in SE Australia due to rapid temperature fluctuations. Although it helps in achieving PH standards, it is not essential.

9 Material costs - Insulation Whole of building envelope average R value of R4.0 (U= 0.25) required for PH in Aus. Product Xtratherm PIR Material Conductivity λ -value R-value (m2k/w) Compressive 10% compression Pricing $/m2 Cost per unit of insulation $/m 2 per R λ0.021w/mk kPa $18.50m2 + GST $15.55 Foil faced PIR Xtratherm PIR λ0.021w/mk kPa $52.74m2 + GST $11.08 Kingspan K5 (suitable for render ) Dow Styrofoam SMTGExtruded Polystyrene (XPS) M Grade Expanded Polystyrene (EPS) VH Grade Expanded Polystyrene (EPS) λ0.020w/mk 4 150kPa $46.40m2 + GST $12.21 λ0.021w/mk λ0.028w/mk kPa $25.00m2 + GST $14.05 λ0.041w/mk (to AS1366) λ0.039w/mk (to AS1366) kPa (to AS1366) kPa (to AS1366) $18.10m2 + GST $4.95 $25.71m2 + GST $6.68

10 Insulation costs cont. Floor finishes range from about $75 to $175per square metre. Product Description Material Conductivity λ -value R-value (m2k/w) Pricing $/m2 Cost per unit of insulation $/m 2 per R Kingspan Plasterboard/Phenoli c insulation laminate K17 or K18 Kingspan Plasterboard/Phenoli c insulation laminate K17 or K18 Kingspan Plasterboard/Phenoli c insulation laminate K17 or K m insulation plus 0.01m plasterboard 0.03m insulation plus 0.01m plasterboard 0.025m insulation plus 0.01m plasterboard (w/mk) λ0.020w/mk 4 $78.47m2 + GST $19.62 λ0.021w/mk 1.43 $44.45m2 + GST $31.08 λ0.021w/mk 1.19 $41.00m2 + GST $34.45

11 Documentation Additional detailing above usual standards more drawings needed! Why? Both for certification requirements & so the builder doesn t take short cuts - doing things properly.

12 Heating and cooling? Will I need it? What is the best approach? What is cost effective locally? Surely it will be complex, expensive and fancy? Domestic hot water more energy than you think HRV integration

13 Recent procurement experience Difficulties in attracting suitable builders Difficulties in obtaining timely, competitive & comparable HRV quotations, HRV suppliers wanting to change specified air flows & ducts Builders to do HRV installations? Utilise commercial A/C contractors? Windows choose carefully

14 Recent procurement - costs Overall cost of a PH, our experience shows ~$3000/m2 (keeping the architecture simple) PH ENHANCEMENTS OVER CONVENTIONAL DESIGN (200M2: $500 - $600K CONSTRUCTION COST) SLAB INSULATION 200m2 x $37 (e.g. 75mm XPS) $ 7,400 ROOF INSULATION 200m2 x $10 (e.g. 200mm mineral wool) $ 2,000 WALL INSULATION 110m2 x $19 (e.g. 150mm EPS) $ 2,100 WINDOWS/DOORS 40m2 can be fitted within a standard budget ($600 - $1500/m2 price range) $ - OMIT CONVENTIONAL HEATING/COOLING & provide 1 x small heat pump -$ 20,000 1 X SMALL HEAT PUMP FOR HEATING / COOLING $ 4,000 HRV $ 15,000 VAPOUR BARRIER TAPED AIRTIGHT $10/m2 $ 3,100 TOTAL $ 13,600 BUILDERS PREMIUM FOR THE UNKNOWN?

15 Recent procurement - costs HRV costs supply & installation $10k+ small installations $15k standard 3BR house flexible ducting $30k larger installation with rigid metal ducting Getting the right builder price variance & bidders pulling out late in tender process Value management at tender but still achieve PH? Windows client understanding of importance and cost

16 Recent certification experience All PH certifiers located in the northern hemisphere, & are not familiar with how we construct buildings locally Unfortunately slow responses to PHPP reviews and technical questions appears typical Local PH certifier? - need to meet specific requirements to become a certifier

17 Case Study - Springdale Australia s first PH Plus? The perfect climate for a PH in Aus? Simple architecture 18month design period Very particular client Off grid and fossil fuel free! Specific building characteristics with reference to the treated floor area Alternative Treated floor area m² Criteria criteria Fullfilled? 2 Space heating Heating demand kwh/(m²a) Heating load W/m² 3-10 Space cooling Cooling & dehum. demand kwh/(m²a) Cooling load W/m² 4-10 Frequency of overheating (> 25 C) % Frequency excessively high humidity (> 12 g/kg) % 0 10 yes Airtightness Pressurization test result n 50 1/h yes yes yes Non-renewable Primary Energy (PE) PE demand kwh/(m²a) Primary Energy Renewable (PER) PER demand kwh/(m²a) Generation of renewable energy kwh/(m²a) yes 2 Empty field: Data missing; '-': No requirement I confirm that the values given herein have been determined following the PHPP methodology and based on the characteristic values of the building. The PHPP calculations are attached to this verification. Passive House Plus? yes

18 Case Study - Springdale 3 bedroom, 175m2 TFA Green Energy Brick Façade Imported Windows - Germany Cleanaire HRV from NZ All electric systems, 10KWp solar PV array, 40KWh usable battery storage 3.5KW electric heat pump for all heating and cooling Construction to commence in April 2016 Image: Off Grid Australia Image: Sustainable building Design

19 Can I have something Close to PH? - observations Many designed without qualified PH designer input HRV without focus on air tightness? Overheating issues Retrofits many challenges particularly thermal bridge reduction, window replacement impacts, EnerPHIT is possible, at what cost?

20 Something close to PH? Beechworth 4 year journey Client desire for 9 star house Couldn t achieve within budget ($2800/m2) 7.6 star rating final result Air tightness membrane, result Recently completed Rented in a flash!

21 What have we learned so far? Results Certified PH design = 8.5 to 9.3 star NatHERS energy rating Air leakage standard sliding doors HRV procurement Client understanding / education Time Don t need all the bells and whistles Big reduction in HVAC size and cost Projected annual energy savings >$2,000

22 Where to next? General public acceptance of what a PH is and how it is such a big improvement on standard practice will lead to wider adoption. Big opportunities in commercial buildings and multi residential, likely to remain boutique in stand alone residential construction - in the short term With practice comes. efficiency time and cost Familiarity

23 Thank you A big thank you to David Halford from Sustainable Building Design for his content inputs to this presentation