Category Archives: Sustainable Architecture

How to Install Insulation

How to Install Insulation

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Insulation needs to be installed with careful attention to detail, as inappropriate or incorrect application will crucially decrease performance. For instance, failure to butt all ends and edges of batts to give a snug fit could mean that about 5% of the ceiling area is not being covered. This could result in losing up to 50% of the potential insulation benefits.

  • Avoid thermal bridges
  • Eliminate gaps in insulation
  • Do not compress bulk insulation
  • Protect insulation from contact with moisture, provide vapour and moisture barriers to prevent condensation
  • Provide a sealed air space of 25mm adjacent to reflective insulation
  • Allow clearance around appliances and fittings

All electrical wiring encased in insulation must conform to AS3000: Electrical installations-buildings, structures and premises. It’s best to keep wiring clear of insulation, e.g. to run wiring on top of ceiling joists.

Neither good performing insulation or a 6 or 7-star energy rating are a guarantee for real energy efficiency. The building envelope needs to be treated as a delicate continuous shell. Each small gap and leakage will impair the performance of the insulation. It is essential to consider the end product in order to determine how energy efficient a building really is. Even small gaps in the insulation such as around windows or other wall penetrations can halve the potential insulation benefits. Adding good performing and appropriately installed insulation can save a lot on your energy bill and minimise the greenhouse gas emission.

Different Types Of Insulation

Different Types Of Insulation


The purpose of thermal insulation in a building is to regulate the internal temperature by minimising or stopping heat transfer through radiation, convection and conduction. Generally speaking, there are two different types of insulation that must work together to prevent heat transfer: Bulk insulation and reflective insulation.

Bulk insulation
Bulk insulation mostly resists the transfer of conducted and convected heat, using millions of tiny pockets filled with still air or other gases within its structure. This air provides the material’s insulating effect, therefore it’s essential not to compress bulk insulation. Bulk insulation is available in different shapes and materials.
-Batts and Blankets (Glasswool/Fibreglass, Wood Fibre Board, Rockwool, Natural Wool, Polyester)
-Loose-fill insulation (Cellulose Fibre, Natural Wool, Granulated Rockwool)
-Boards (Extruded Polystyrene, Foil-faced expanded polystyrene, Wood Fibre)

Reflective insulation
Reflective insulation mainly resists radiant heat flow. It is made of thin sheets of highly reflective aluminium foil, which reflects heat from its polished surfaces. The performance relies on the presence of an air layer of at least 25 mm next to the reflecting surface. Keep in mind that dust will greatly reduce the performance. Some examples include:
– Reflective Foil Laminate
– Multi-Cell Reflective Foil Products
– Expandable Concertina-Style Foil
– Foil Bonded to Bulk Insulation
For information about electrical safety checks for householders with foil insulation go to ‘Home Insulation Program’ webpage from the Australian Government.

Why is Insulation so Important?

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Thermal insulation is a fundamental factor to achieve thermal comfort for occupants. Insulation reduces undesirable heat loss or gain and can lower the energy demand on heating and cooling systems.

Insulation is the most effective way to improve the energy efficiency of a building, as it acts as a barrier to heat transfer.

It will keep the house warm in winter and will help to stay cool in summer, improves thermal comfort and well-being, and minimises condensation on walls and ceilings. Furthermore, insulation needs to be combined with appropriate shading devices to windows and adequate ventilation possibilities, otherwise heat entering a building through windows will be trapped inside by the insulation and lead to overheating.

Older houses in particular pose a problem: inadequate insulation, poor solar access and air leakages amongst other things lead to unwanted heat gain and loss, and consequently higher energy bills.

Adding insulation to a home can save 45-55% of mechanical heating and cooling needs and as a result, save non-renewable resources and reduce greenhouse gas emissions. With the current energy prices, additional insulation usually pays for itself in around five to six years. With the prospect of rising energy prices it’s more than likely that insulation retrofitting will pay off even quicker.

Thermal Comfort and Star Ratings

Thermal Comfort and Star Ratings

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As explained in our previous article: the perception of temperature is more important than the temperature itself, when it comes to comfort.

In Australia, energy rating assessments are done pre-construction, assuming competent application of all insulation and building materials as well as draught sealing all wall penetrations.

However, common construction practices often demonstrate misapplications and air leakages. Sadly, although there are regulations in place on how to install insulation and how to seal of wall penetrations, there is no one really responsible for checking all those details, neither the builder, nor the architect, nor the building surveyor. In fact, some tradies even take out insulation, so that they can work easier around cables, fixtures and fittings and don’t bother to put the insulation back in. For sure, as soon as the plasterboard sheets are one no one can even see the problem.

This means that although in theory the house should be energy efficient, the reality will be far from that. It will be draughty inside. Cold air can come in. The energy bills will be way higher than the energy rating did predict. And, as explained in our article about thermal comfort, it will be hard to feel comfortable inside your ‘well insulated’ home.

In Europe, energy efficiency is most often assessed or checked post construction, with special attention to the prevention of thermal bridges. Some countries require airtight buildings, and amongst other things, double glazing, solar energy for hot water and heating systems, the usage of storm water, greywater recycling, recycled materials and product life cycle considerations to minimise energy demand and carbon footprint.

Conclusion

A good star rating, well performing insulation and building materials are not a guarantee for well performing homes and for feeling comfortable inside the house. The building envelope needs to be treated as a delicate continuous shell. Each small gap and leakage will impair the energy efficiency and the well being of the occupants. It is essential to consider the end product in order to determine how energy efficient a building really is.

What Factors are Influencing Thermal Comfort ?

What Factors are Influencing  Thermal Comfort ?

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Carlos Gali Photography
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If insulation applied is faulty or insufficient, the exposed surfaces in a room will stay significantly colder in winter or hotter in summer than the room temperature. Although the heater pumps hot air into a room, or the air-conditioning blows cool air, the thermal radiation will affect the equilibrium. The Mean Radiant Temperature is affected negatively and the occupants won’t feel comfortable.

  • The ceiling isn’t insulated or the insulation is penetrated for example because of the installation of down light. As warm air is always moving upwards, heat is lost to the cooler air in the roof space.
  • Air leakage around doors, windows, down lights, pipes, and other wall penetrations are exceeding the acceptable Relative Air Velocity.
  • Wrong application of thermal mass can influence the Mean Radiant Temperature and can therefore increase the need of mechanic heating and cooling.
  • Under- performing windows and doors (when air is able to leak in/out of poor fitting doors and windows) are also influencing the Mean Radiant Temperature and the Relative Air Velocity.

When it comes to comfort, the perception of temperature is more important than the temperature itself.
For a person to feel comfortable, the difference of temperature between the head and the feet should not exceed 2.5 degrees. This demonstrates the importance of floor insulation and this explains why we usually feel more comfortable standing barefoot on carpet than on tiles.

Do you want to know more about the basics of Thermal Comfort, please have a read through our article What is Thermal Comfort?

What is Thermal Comfort?

What is Thermal Comfort?

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Human thermal comfort describes the state of mind that expresses satisfaction with the surrounding environment and refers to several conditions in which the majority of people feel comfortable.

The human body produces heat depending on the level of activity, and expels heat according to the surrounding environmental conditions.

The body loses heat in three main ways:  radiation, convection and evaporation. An unpleasant sensation of being too hot or too cold (thermal discomfort) can distract people from their activities and disturb their well being. This may reduce the ability to concentrate and decrease motivation to work. Thermal comfort is affected by six variable factors which are needed to maintain a healthy balance in order to sustain satisfaction with the surrounding environment.

1) Air Temperature is the most common measure of thermal comfort and can easily be influenced with passive and mechanical heating and cooling.

2) Mean Radiant Temperature is the weighted average temperature of all exposed surfaces in a room. The greater the difference between air temperature and exposed surfaces, the greater the Relative Air Velocity.

3) Relative Air Velocity (‘wind chill factor’) is the apparent temperature felt on exposed skin due to wind.  For example, if cold air is leaking in from a window, the air temperature feels lower than the actual air temperature, hence the increased likelihood of feeling cold, even when the heater is on.

4) Humidity or relative humidity is the moisture content of the air. If the humidity is above 70% or below 30% it may cause discomfort.

5) Activity Levels can reduce the heating needs, as lower air temperature is acceptable when occupants have higher activity levels.

6) Thermal Resistance of clothing or warm blankets in a bedroom can reduce the need of heating.

Building design is affected by the first four of these thermal comfort variables. The last two depend on the action and behaviour of the occupants.

Do you want to know more about thermal comfort? Then have a read through our article what factors are influencing thermal comfort.

Surface-Area-To-Volume Ratio / Building Shape

Surface-Area-To-Volume Ratio / Building Shape

Surface-Area-To-Volume-Ratio

The surface area to volume ratio (S/V) is an important factor for the performance of a building. The greater the surface area, the greater the potential heat gain or loss through it. Consequently, a small S/V ratio implies minimum heat gain and heat loss. In order to minimise unwanted losses and gains through the fabric of a building, it’s desirable to design a compact shape, without articulation.

In theory, the most compact building would be a cube. This configuration may not be acceptable for many reasons, such as restrictions to daylight access, site and neighbouring character, planning regulations or simply personal preferences. However, to minimise heat transfer through the building envelope, the building shape and accordingly the floor plan itself, should be as compact as possible. With straight walls and first floor wall on top of ground floor walls. Deleting the need for additional roofing over nooks and grannies in the ground floor areas that stick out.

When designing your home consider thoughtfully what rooms are really needed. Instead of adding rooms you might need. Create multifunctional rooms, spaces that can be used for more than one function and that can easily adapt to a changing lifestyle.

Unfortunately this design principle isn’t supported by most council, as typically planners do not support straight walls without articulation or sheer double storey walls. We are currently working on a town house development in Kingston Council. In our original design we had all first floor walls sitting on top of the ground floor wall. In order to reduce wall and roof areas and hence to optimise energy efficiency. But regrettably, council forces us to step in the first floor walls. As they call it: to create more interest and articulation.

 

 

How to Organise a Floor Plan

How to organise a floor plan

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Rooms are utilised for distinct purposes at different times of the day and their placement will influence energy efficiency as well as comfort levels. Zoning means the creation of zones by grouping rooms with similar uses, and closing off unheated rooms, such as laundries or guest bedrooms, to reduce heating and cooling needs. It is important to separate heated and unheated areas with doors, such as glass or bi-fold doors to help retain the open-plan aesthetic if required.

  • Daytime living areas such as family rooms, kitchen and rumpus rooms should be north facing.
  • Avoid orientation and windows to the harsh west sun, especially for living rooms and bedrooms.
  • Locating the garages or carports to the west, east or south can protect the building from summer sun and winter wind.
  • Areas that use water (hot water in particular) should be grouped together to minimise heat loss from pipes, plumbing costs and water wastage.
  • Create buffer zones to the west and south, as this is where most of the unwanted heat gain or loss will occur, such as bathrooms, laundry or storage rooms.
  • Avoid self-shading; deep north facing courtyards, garages or other deep articulations should not overshadow north-facing windows.
  • Air-locks to external doors are essential to reduce the loss of heated air when the external doors are opened.
  • Allow for cross-ventilation. Openable windows and external doors should be located on different      sides of the home, with less than 8 metres distance between them to create air flow.

If you do want to know more about optimal house siting and how to place a building for optimal solar access please check out our other articles.

Optimal House Siting

Optimal House Siting

HOUSE siting
In order for a building to be energy efficient and environmentally friendly in any way, there are many things to consider when searching for a site or placing a house on a site.

Analysing needs and lifestyle – current and future

  • What type of home is needed?
    (house, apartment, villa; is a large garden required, lifestyle options and access to facilities)
  • Does the location suit your lifestyle and can it accommodate potential changes in the future?
    (family addition, retirement, old age, health and so on)
  • Is the site close to public transport, work, school, family members or other social activities?
    (Proximity may reduce the need of a second car. It will reduce car trips, travel time and carbon footprint, consequently protecting the environment, and saving money).
  • Determine the true cost of the location.
    (A site/ home in the outer suburbs may be cheaper, but will this compensate the higher transport cost and the additional times spend on the road or on public transport?)


Study the site and the local climate

  • Seasonal and diurnal temperature ranges
  • Direction of hot, cold and wet winds and cooling breezes
  • Humidity range
  • Effect of local geographic features or climate conditions, like the fall of a site, vegetation or neighbouring properties that might modify air movement and solar access.
  • Seasonal characteristics
  • Orientation of the site, determine where north is. Will the configuration of the site allow for good solar access, and the positioning of private open space and garden areas facing north?
  • Are existing or proposed buildings or trees overshadowing the site?

If you do want to know more about how to place a building on your site and how to arrange your floor plan for optimal solar access please check our other articles.

 

How to Place a Building

How to Place a Building

how to place a building

In hot climates with negligible heating needs, the building should be orientated to maximise exposure to cool breezes. The construction should aim to exclude harsh sun all year around, by minimising window sizes and/ or providing large overhangs or other effective shading devices.
All other climate zones, as well as alpine zones, need to incorporate passive solar heating and cooling. The extent of heating and cooling requirements depends on the climate. To determine if you need mostly passive heating, passive cooling, or a combination of both, you can compare summer and winter energy bills, consult a designer or an architect, or check meteorological records on the Australian Bureau of Meteorology website.
In the southern hemisphere, living areas should be ideally orientated within the range of 15°W-20°E of true or ‘solar’ north (20°W-30°E of true north is considered acceptable). Accurate location and direction will enable standard overhangs to prevent overheating in summer and allow lower winter sun to heat the building with no extra costs or effort from the occupants. On the other hand, a poor orientation will result in heat loss in winter and will lead to overheating in summer, by allowing low angled west or east sun to strike glass surfaces. North facing walls and windows should be set back significantly from large obstructions to the north, like trees, fences and other buildings. Keep in mind that they cast shadows two to three times their height in mid-winter. The distance to a single storey building to the north should be minimum 5.5 metres, to a double storey at least 10 metres.

  • If possible, garages, carports and other buildings or structures shouldn’t be placed on the northern side of the site.
  • Consider sharing walls with neighbours, especially on the east or west boundary as it will minimise unwanted heat loss or gain through these walls.

If you do want to know more about optimal house siting and how to arrange your floor plan for optimal solar access please check out our other articles.