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1. Elizabeth Wilhide's 'ECO'

   In this section, I will be referring to the research and work of Elizabeth Wilhide in their book ‘ECO’, an essential sourcebook for environmentally friendly design and decoration. 

   

   Elizabeth Wilhide's 'ECO'

2. 1. Siting and Orientation

   Wilhide discusses how it’s important to understand that the location of a building has a direct impact on its performance. It’s important to consider the following:

   • The local ecology of the site
   • Its gradient
   • Orientation
   • Exposure to sun, wind, and rain
   • Regional climate

   Additionally, when designing with the sun and the climate in mind, the design needs to adapt to its location. Passive heating and cooling is a big consideration. 

   

   Threepwood Passive House by Team Green Architects

3. Passive Heating:

   For example, designing a home for the southern hemisphere, you will want to:

   • Build on a north-facing hillside, offering opportunities for solar gain and thermal shelter
   • Consider the sun's strength, angle, and path across the site, paying attention to obstacles that may shade the site
   • In cold areas, take advantage of the sun to warm your building. This includes the north side being up to 60% windows, while the south remains more enclosed
   • Large windows let sunlight in during the winter
   • If designing a two story home, due to warm air rising, living areas should be placed on the first floor and bedrooms on the ground floor
   • In cool climates, the site should ideally be level or slightly elevated and major openings such as doors and windows shouldn’t face prevailing winds, as cool air collects in hollows so you want to reduce the amount of empty space that heat can be lost from
   • Heat loss can also be reduced by setting the building back into a slope as the earth absorbs heat more slowly than air but retains it for longer, so will be warmed by the ground when the weather turns cooler

   

   Passive solar design example in Threepwood Passive House by Team Green Architects

4. Passive Cooling:

   For example, designing a home for the southern hemisphere, you will want to:

   • Place overhangs and eaves to prevent overheating in the summer
   • In warm climates, you want to leave air spaces under/in the house, and face doors and windows towards prevailing winds to passively cool the home
   • Cross-ventilation can be utilsied by opening doors and windows opposite to one another to draw prevailing winds from one side of the house, through to the other by pressure differences, cooling the home
   • With warm air rising, high-level windows, skylights, or passive thermal chimneys can be used to draw warm air upwards and out of the house
   • Framing a house with plants that can grow up to provide a living screen will also help to keep the building cool

   Overall:

   • Internally, living areas should be placed on the north (maintain warmth in bedrooms), while service areas such as kitchens and bathrooms should be placed on the south (keep them cool)

   

   Passive solar design example in The Bent Annexe by BENT Architecture

5. 2. Construction and form

   Elizabeth Wilhide’s ECO also discusses the importance of construction and form in efficient and sustainable design. 

   The way in which materials are used can make them energy efficient or not. 

   Timber framing is ecological as wood is a renewable resource and has low embodied energy (see lesson two for more on this). Efficiency can be increased when:

   • The basic structure is a lightweight timber frame
   • The structure is designed so that water runs off and air circulates freely
   • A ‘breathing wall’ system is implemented where the cavity between the outer and inner timber walls are insulated with cellulose fibre (made from recycled newspaper) and treated with borax to promote fire-resistance
   • External walls are well-insulated
   • Internal walls are made of high-mass materials such as concrete or brick
   • Overhanging eaves are added to protect wood-clad structures from water penetration 

   

   Timber core wooden framing

6. Adobe and rammed earth are efficient as they are formed from very ecological earth and they absorb heat during the day and slowly release it into the interior of the building at night. Efficiency can be increased when:

   • Each type of wall sits up on elevated foundations of concrete block or stone so they are not eroded by water

   

   A contemporary, rammed-earth home in Jalisco,Mexico, by Tatiana Bilbao

7. Straw Bale is ecological as it’s a common agricultural waste product of the dried stalks left after grain crops are harvested and have the opportunity to be recycled into walls. Efficiency can be increased when:

   • Walls sit up on elevated foundations of concrete as wide as the bales to protect against moisture penetration
   • The bales need to be wrapped in wire to allow breathable external stucco and internal plaster to be attached
   • Bales should be up to 60cm thick, providing excellent qualities of sound and heat insulation

   

   Straw bale walls

8. Earth-sheltering and turf roofs are ecological as they replace land lost in construction. Efficiency can be increased when:

   • They are seeded with wildflowers and native grasses to support local conditions

   

   Turf roof by Prentiss Balance Wickline Architects

9. 3. Energy Efficient Insulation

   Energy efficiency is made up of a range of strategies, however, Wilhide says insulation is key. How well a structural element such as a wall or roof insulates, is expressed as its U-value - heat transmission coefficient. The lower the U-value, the higher the degree of insulation. 

   Energy efficiency can be increased by using insulating materials, with eco options including cellulose fibre. As discussed earlier, this is made from recycled newspaper and is treated with borax to promote fire-resistance. Other eco insulating materials include wood fiberboard, sheep’s wool and panels, and rope made of flax.

   

   Cellulose fibre insulation

10. Aiming for passivhaus, whereby the insulative properties of a building are so good that they become ultra-low energy structures, requiring little to no energy for heating and cooling, is a great step to take in reducing energy usage and loss.

    The types of materials you use can also determine the energy efficiency of the home. Wilhide discusses how heat always takes the path of least resistance through materials such as metal (any metal joinery), and single-glazed glass. These materials create cold bridges where there is a pathway between the cold exterior of a building and the interior wall surface, causing high temperature drops. 

    These cold bridges should be prevented and this can be done by:

     

    • Tight sealment of window and door frames
    • Double or even triple glazing glass

     

    As discussed earlier, heat can also be retained by using heavy, massive foors and walls made of materials such as concrete, stone, and brick. These heat up slowly during the day and release it overnight. 

    

    Passivhaus wall construction

11. 4. Power

    According to Wilhide, solar energy technology has significantly improved over the past few decades. There are now two active ways of harnessing the sun's energy, through thermal solar energy and photovoltaics.

    Thermal solar energy systems generally use solar collectors to heat water or air in a home

    The pros are that:

    • They can be fitted to existing roofs, adjacent structures, and in the garden

    .

    The cons are that:

    • They produce heat when demand is lowest

    

    Thermal solar energy panels on house roof

12. Photovoltaic systems use collectors to convert radiant solar energy into electricity that can be stored and used later.

    The pros are that:

    • Surplus energy can be put into the national grid and homes can make an income
    • An average solar-powered houses saves a tonne of CO2 every year
    • They can be adapted for a wide range of applications
    • They come in solar panels, and now solar tiles, slates, and translucent cells

    .

    The cons are that:

    • They have a working life of over 20 years
    • Major changes in your lifestyle are required in order for photovoltaic systems to support a home (use less energy than normal)

    

    Photovoltaic system on house roof

13. Wood-burning stoves have also become more environmentally friendly. This is because wood is a renewable resource and new clean-burning systems minimise smoke emissions while maximising heat delivery.

    The pros are that:

    • They can store heat for a very long time
    • Wood that is found and used in wood-burning stoves is sustainable

    .

    The cons are that:

    • They are not an efficient way of heating water

    

    Wood-burning stove in living room

14. 5. Natural and artificial light

    Light is a very important resource within homes as it is connected to emotional and physical wellbeing.

    To utilise natural light, consider introducing light into areas that would receive little direct sunlight. This can be done by:

    • Placing windows up high in a wall to allow more light to penetrate further
    • Placing skylights above connecting areas such as hallways and staircases
    • Placing internal windows through solid walls to spread light through cutoff spaces

    

    Natural light use in homes by Generation Homes

15. To utilise artificial light, consider using low-energy lighting, such as energy saving or compact fluorescent bulbs which have the benefits of:

    • Producing six times as much light as ordinary bulbs (wattages and power can be much lower)
    • Lasting eight times longer (at 8,000 hours instead of 1,000)

    

    Artificial light use in kitchen pendant light

16. 6. Water and waste

    Freshwater is a very valuable resource and there are several ways which you can reduce water usage.

    Firstly, rainwater collection can be implemented in a home or public setting, drastically saving the need for use of damned water or bore water.

    The pros are that:

    • Catching rainwater is free once you have the setup
    • It can ensure a domestic water supply for drinking after a filtration and purifying system is implemented, showering/bathing, flushing toilets, running washing machines, watering gardens, washing cars, etc.

    .

    The cons are that:

    • The system has to be set up effectively so that water efficiently runs off a roof from a specific direction (on specific roofing materials such as corrugated iron), and into gutters, which take the water into large storage tanks that can be hard to hide from sight
    • Pumps to deliver the water, as well as filtration and purification systems are expensive

    

    Rainwater collection tanks

17. Secondly, greywater systems are a great way of recycling washing, bathing, or showering water. To use greywater, it must be filtered and treated to remove the risk of disease and plumbing blockages. 

    The pros are that:

    • It can be used for garden irrigation and to flush toilets, reducing the use of ‘clean’ water

    .

    The cons are that:

    • The system for filtering and biologically purifying greywater needs to be carefully designed to avoid pollution by groundwater
    • They are very demanding in the area of land they require

    

    Greywater reed bed system

18. Thirdly, composting toilets dramatically cut down water consumption. A shaft leads waste to a large container under the toilet, where circulating air breaks down the waste matter while an exhaust vent extracts smells. This produces organic compost that can be removed every couple of years.

    The pros are that:

    • Huge water savings as water-flushing toilets consume a lot of water
    • Organic compost is produced which can be dug into gardens, providing free, nutrient-rich compost

    .

    The cons are that:

    • The setup of the waste storage container may be difficult, especially when designing for a building without a basement

    

    Compost toilet

Why we need to rethink how we build with Ged Finch - youtube

Green buildings are more than brick and mortar with Bryn Davidson - youtube

Sustainable apartments - a new model for the future with Jeremy McLeod - youtube