energy efficiency - lunch & learn

Wood and Energy EfficiencyLightweight Timber Framed Construction and NSW’s BASIX Thermal Comfort

Wood and Energy Efficiency – Lightweight Construction © FWPA 2011

Learn more about wood at UTAS

Centre for Sustainable Architecture with WoodGraduate Certificate in Timber (Processing & Building)• 4 units, part time, onlineAreas covered include:• Wood science• Design for durability and service for life• Timber as a renewable resource• Sustainable design and construction• Engineered wood products• International technologies and developments• Plus, selected topics of individual interestMore information: Associate Professor Greg Nolan (03) 6324 4478 or [email protected]


Learning Objectives

After this presentation you should be able to:– Understand the thermal comfort methods of

BASIX– Understand the thermal properties of wood– Understand how wood products can meet BASIXs

thermal comfort requirements

For architects - AACA Competencies:– Design– Documentation


This Presentation

• Thermal comfort requirements of BASIX• How wood-based construction systems can

meet these requirements• Simple techniques to insulate:

– walls, roofs– sub-floor

• Ventilation issues• Smart use of thermal mass


BASIX - Thermal Comfort Requirements

Methods:– Simulation (AccuRate, BERSPro, Firstrate5)

• Whole house must not exceed maximum (separate) heating and cooling loads

– Deemed-to-satisfy• DIY• Rapid – simple single storey detached dwellings

– All methods require some form of additional insulation


Thermal Properties of Wood

Timber / wood product Density (kg/m3)

Thermal conductivity

(W/m.K)

Thickness(mm)

R-value(K.m2/W)

Framing timber - kiln dried hardwood (across the grain)1

677 0.16 12 0.0819 0.1250 0.31

100 0.621 000 6.25

Framing timber - radiata pine (across the grain) 1

506 0.10 12 0.1219 0.1970 0.7090 0.90

1 000 10.00Particleboard flooring1 640 0.12 19 0.16

22 0.1825 0.21

1 000 8.33Plywood flooring1 530 0.14 6 0.04

12 0.0919 0.1425 0.18

1 000 7.14

1calculated based on values and method provided in BCA 2010 Volume One Specification J1.2 Table 2a.


R-values for Timber Framed Elements


Roof

Insulation is required in all climate zones in NSW


Walls

Insulation is required in all climate zones in NSW


Floors

• Increase in floor system R-value required in most climate zones in NSW

• Additional insulation required in Rapid Method


Floors: BASIX requirements

BASIX Requirements - (DIY Method)Typical Insulation Options for Suspended Floor Construction

(for floors without floor heating system)

Climate Zone 2 4 5 6 7 8 2 4 5 6 7 8Perimeter Treatment Enclosed Unenclosed

Minimum required Total

R-value0.7 1.7 1.3 1.7 2.0 2.5 0.7 2.0 1.5 2.0 2.5 3.0

Total R-Value of Framed and

Concrete Floor Systems

0.7

Minimum additional R-

value required (down)

Nil 1.0 0.6 1.0 1.3 1.8 Nil 1.3 0.8 1.3 1.8 2.3


Floors: Increase system’s R-value

• Additional insulation techniques:1. Insulate above the floor (e.g. carpet)2. Enclose sub-floor perimeter wall3. Decrease air-flow:

• Cover ground with plastic / halves ventilation• Install cavity barrier into external wall cavity

4. Insulate under floor:• Insulate sub-floor perimeter wall • Insulate directly under floor


Sub-floor: Enclose sub-floor perimeter


Floors: Enclose sub-floor perimeter

• Increase R-value of perimeter enclosure - depends on height of floor above ground

• Can increase system R-value by R1.0


Floor: Decrease sub-floor air flow

Decrease air flow – Cover ground with plastic– Reduced ventilation requirements

Source: BCA 2010 Volume Two Figure 3.4.1.2


Floor: Cavity barrier

Increases R-value of floor by at least R0.5


Floor: Insulation below the floor

Additional insulation below ground floor:– Insulate inside of sub-floor perimeter wall

• May be cheaper• Thermal connection maintained with ground (better for

hot conditions)

– Insulate under the floor• Foil integrated with flooring (e.g. R-Flor – no gluing

issues)• Under floor joists with plywood, foil etc• Bulk insulation


High Mass House

Solar Mass House


Energy Efficient Housing

• High mass house– Main features and limitations– Pending research

• Lightweight house– Main features and benefits

• Hybrid and combination houses


High Mass House: Main features

Main design features:– Zoned design with living rooms to the north and

bedrooms to the south. Main heating in living areas– A length-to-width ratio of approximately 1 to 1.5 on

the E-W axis– Cavity/solid brick and slab-on-ground construction– Ceiling and walls may be insulated (recommended

values vary with climate)


High Mass House: Main features

Main design features:– North facing windows, sometimes with a

recommended area as a function of floor area– No, or minimum glass facing east and west– Shading devices to windows during summer

• e.g. eaves projection, deciduous trees for north facing windows

• shutters etc. for east and west facing windows


High Mass House

To operate properly requires:– Clear exposure to north facing sun– Site that allows for building on East-West axis– Living room (and other) windows ‘unscreened’

during winter days to allow sunlight penetration– Construction method that allows for wall and

ceiling insulation


Thermal Mass

How much mass is required?– Suggested that 1,200 kg of thermal mass per m2

will produce a zero heating house in cold European climates (Vale and Vale 2000)

– Southwell, UK – 723 kg/m2 sufficient (Vale)– Bairnsdale, AUS – 580 kg/m2 sufficient

(Oppenheim) – More theoretical work needs to be undertaken for

temperate climates


Thermal Mass

Suitable when:– Climate is suitable

• Diurnal range > 8 degrees

– Site is suitable• Allotment is oriented and sized adequately


Diurnal Range

ZONE DESCRIPTION DIURNAL RANGE1 High humid summer, warm

winter Lowest diurnal (day/night) temperature range

2 Warm humid summer, mild winter

Moderate to low diurnal (day/night) temperature range. Can vary significantly between inland to coastal

3 Hot dry summer, warm winter

Significant diurnal (day/night) range

4 Hot dry summer, cool winter

High diurnal (day/night) temperature range

5 Warm temperate Low diurnal (day/night) temperature range near coast to high diurnal range inland

6 Mild temperate Low diurnal (day/night) temperature range near coast to high diurnal range inland

7 Cool temperate Low diurnal (day/night) temperature range near coast to high diurnal range inland

8 Alpine Low humidity, high diurnal range

Source: Your Home Technical Manual


Lightweight House


Lightweight House

• Structural framework supports the building• Other materials provide spatial separation and

infill• Great flexibility • Providing excellent operational environmental

performance


Lightweight Timber: Benefits

• Less sensitive to orientation and solar access• Northern orientation is not critical• Provides much more flexibility for sighting on

a block• Greater flexibility in design, layout and

internal zoning• Adaptable over time


Lightweight Timber: Benefits

• Reduced capital costs compared with mass house

• Ease of construction – no cut and fill on sloping blocks, easy installation of insulation in walls and ceiling.

• Reduced carbon footprint through whole life


Lightweight Timber: Cost effective

Source: Think Brick (2009) Wasting Energy. Available at http://www.thinkbrick.com.au/assets/documents/position_papers/PP2-Wasting-Energy.pdf

$20,0000 100 kWh/pa


Lightweight Timber: Cost effective and energy efficient

• Largest difference is 100 kwH per annum to heat/cool• Extra cost ~ $20 per year• Compare cost of construction:

– insulated double brick $52,000– insulated timber $32,000 – saving $20,000

• House life >1,000 years to pay for the difference• Enough to buy a big solar power system and make house

greenhouse neutral• Calculations don’t include the greenhouse gases emitted in

brick production or absorbed during tree growth


Lightweight Timber: Lower carbon footprint

• Total GHG emissions - 5 star

Insulated steel frame, brick clad, suspended

steel

Insulated steel frame, brick clad and concrete

slab

Insulated timber frame, brick clad and concrete

slab

Insulated timber frame, brick clad, suspended

timber

Insulated timber frame, timber clad, suspended

timber

Melb 137.088000000001 137.088000000001 131.04 127.008 120.96

Sydney 73.584 72.576 66.528 63.504 56.448

Brisbane 78.624 77.616 71.568 68.544 61.488

10

30

50

70

90

110

130

Melb Sydney Brisbane

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Lightweight Timber & Thermal Mass

The difference in thermal mass between standard new build masonry and insulated lightweight timber frame construction is not a significant factor affecting either thermal comfort or energy consumption, now or within the lifetime of the building.


Lightweight Timber: Lower carbon footprint

• GHG emissions reductions using timber


Wood is an insulator

Thermal image


Hybrid house

The heavy mass and lightweight house hybrid: • It’s not always a simple decision of either/or! • If site allows access to some northern sun,

mass can be incorporated in specific locations to use the solar heat in wintere.g. composite concrete/timber with lightweight timber-frame walls


Composite concrete/timber floor

http://www.timberawards.com.au/winners/awards-winners-2010

http://www.facebook.com/pages/Australian-Timber-Design-Awards/161099300764

http://www.timberawards.com.au/component/mailto/?tmpl=component&link=aHR0cDovL3d3dy50aW1iZXJhd2FyZHMuY29tLmF1L3dpbm5lcnMvYXdhcmRzLXdpbm5lcnMtMjAxMA==

http://www.timberawards.com.au/images/stories/2010/wolgan-valley-01-600x275.png










http://www.timberawards.com.au/images/stories/2010/transformer-house-01-600x400.png








http://www.timberawards.com.au/images/stories/2010/whale-of-a-beach-01-600x400.png










http://www.timberawards.com.au/images/stories/2010/timber-staircase-01-600x400.png







http://www.timberawards.com.au/images/stories/2010/glasshouse-01-600x400.png










http://www.timberawards.com.au/images/stories/2010/office-development-surrey-hills-01-600x400.png










http://www.timberawards.com.au/images/stories/2010/gwinganna-lifestyle-retreat-01-600x400.png










http://www.facebook.com/pages/Australian-Timber-Design-Awards/161099300764

http://www.timber.net.au/

http://www.timberstewardship.org.au/

http://www.woodcouncil.org.au/

http://www.tdansw.asn.au/


Combination Lightweight House

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Learn more about wood at UTAS

Centre for Sustainable Architecture with WoodGraduate Certificate in Timber (Processing & Building)• 4 units, part time, onlineAreas covered include:• Wood science• Design for durability and service for life• Timber as a renewable resource• Sustainable design and construction• Engineered wood products• International technologies and developments• Plus, selected topics of individual interestMore information: Associate Professor Greg Nolan (03) 6324 4478 or [email protected]


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