Insulation

Overview

Insulation acts as a barrier to heat flow and is essential to keep your home warm in winter and cool in summer.  Insulation can assist with weatherproofing and eliminate moisture problems such as condensation.  Some types of insulation also have soundproofing qualities.  A well insulated and well designed home will provide year round comfort, cutting cooling and heating bill by up to half.  This, in turn, will reduce greenhouse gas emissions.

So how does it work

Insulation products come in two main categories – bulk and reflective.  These are sometimes combined into a composite material.  There are many different products available.  To compare the insulating ability of the products available look at their R-value, which measures resistance to heat flow.  The higher the R-value the higher the level of insulation.  The Building Code of Australia sets out minimum requirement for materials R-values used in construction of buildings.  It is generally advisable to exceed these for greater comfort and energy savings.

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Choosing the right level of insulation for our climate

Within Ballarat area, even though we have some hot days in summer, the main priority for building design is to reduce heat loss in winter.  This makes sense if you think of the amount of time you spend actively heating your home during the winter months, compared with the select number of days during summer where temperatures reach uncomfortable levels.  Luckily insulation can help with both.

As outlined above, all insulation has a rating which measures resistance to heat flow.  The higher the R-value the higher the level of insulation.  For the Ballarat climate, it is recommended that you have a minimum of the following R values.

  1. External walls – R=2.8
  2. Ceilings – R=4.1

It is also recommended you insulate your floor in cool climates like Ballarat.

  1. Floors – R=?

Selecting from the different insulation on offer

There are two main types of insulation (1) bulk and (2) reflective.

Bulk insulation mainly resists the transfer of conducted and convected heat, relying on pockets of trapped air within its structure.  Its thermal resistance is essentially the same regardless of the direction of heat flow through it.  Bulk insulation includes materials such as glasswool, wool, cellulose fibre, polyester and polystyrene.  All materials come with one material R-value for given thickness.

Reflective insulation mainly resists radiant heat flow due to its high reflectivity and low emissivity (ability to re-radiate heat).  It relies on the presence of an air layer of at least 25mm next to the shiny surface.  The thermal resistance of reflective insulation varies with the direction of heat flow through it.  Reflective insulation is usually shiny aluminium foil laminated onto paper or plastic and is available as sheets (sarking), concertina-type batts and multi-cell batts.  Together these products are known as reflective foil laminates or RFL.

Which one suits you?

Deciding which type of insulation best suits your home can be a challenge. Luckily there are a number of resources to help you decide:

  1. Visit the Smart Living Centre, we have an extensive display of different types of insulation
  2. Check out RENEW, a DIY sustainability magazine produced by the Alternative Technology Association have compiled a series of buyers guides, including one on insulation, to provide consumers with independent advice on sustainable products for their home.  These can be purchased on-line, or you can pop into the Smart Living Centre and pick up a hard copy for free.
  3. Check out these fact sheets from from Sustainable Energy Authority of Victoria (now Sustainability Victoria) and the Australian Government’s Your Home Technical Manual which provide summaries of the different types of insulation on offer and their potential application and are a good place to start in determining what will best suit your needs.
  4. Choice have also prepared a Home Insulation Buying Guide for things to look out for when making your purchasing decision