Insulation R-Value in Melbourne

Looking to get insulation installed in an older Melbourne house. First quote is good value, however wondering if anyone has any practical advice with R-values. The guy has told me that there is no noticable difference between R4 and R5, and googling is really just telling me the minimum required in each area (seems like R4 is okay for Melbourne).

Thanks in advance!

Comments

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    if anyone has any practical advice with R-values. The guy has told me that there is no noticable difference between R4 and R5,

    Its as simple as this, the higher the R value the better it keeps heat in or out. So go the highest you can fit/afford.

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      Does the same apply for keeping cold in/out?

      There doesn't seem to be a huge difference in price, so why would anyone buy anything other than the highest insulting value?

      • -1 vote

        I think it's probably diminishing returns on price to value. The highest rating may cost a lot more than the efficiency it gains.

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        Does the same apply for keeping cold in/out?

        Yes the same applies for cold as well.

        In very simple terms, insulation stops the flow of heat/cold from one side to the other.

        So the cold can't get in or out, the same for heat.

        Lots of people think 'but I want the warm winter sun to warm up the house', no you don't. As this means in the evening the cool winter night also sucks away heat from the house.

        Really heavily Insulated houses, only require small amounts of heating and cooling to keep them at temp all year round, as they just don't lose or gain massive amounts of heat/cold from/to the outside.

        Europe with freezing winters etc, have really well built places, with double, double glazed windows. Yes two sets of double glazed windows! In Australia its lucky to even see double glazing!

        There doesn't seem to be a huge difference in price, so why would anyone buy anything other than the highest insulting value?

        Agreed. Normally because the sales person wants to get a sale at all costs, so sells the cheapest thing possible for those shopping around without explaining that for a slight extra you can have something way better.

        When I did my roof last time, I put the largest batts I could get in there and its been amazing! The cost was next to nothing increase and the savings from heat/cooling have been massive. The ducted heater runs 1/3 of what it use to.

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          Yeah, the front of my house is heritage listed, so I can't do too much in terms of insulation, but the back of my house is all double glazed and well insulated and the difference is massive.

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            @Burnertoasty: Yeah kinda makes it hard, there are products around you can install on the existing windows.

            The cheapest would be if you don't open the windows at all, then you can get a sheet of glass installed on the inside, to give you that double glazed saving, but you can't open the windows. Keeps the outsize look the same.

            If you open them, there is also a product around that sicks on the glass (think window tinting) that is a really thick clear plastic, and it offers a higher level of heat loss etc compared to normal glass.

            Depending on the style of window, you can install double glazed panes into them, if they are thick enough and strong enough to carry the weight.

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            @Burnertoasty: So they won't let you do above the ceiling and below the roof sheeting?

            I did both on my old place (1930s) and it made a massive difference, especially nailing sarking with the reflective side outwards under the terracotta roof tiles.

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    I just changed my windows from crappy single pane and poorly sealed to double glazed and well sealed. R2 reused temporarily until plastering.

    That made a huge difference.

    Changed old R2 to new R4 and finished off the plaster.

    No diff.

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    Check out the second graph.

    https://www.energyvanguard.com/blog/76941/The-Diminishing-Re...

    to convert Imperial R- values to Metric R-Values multiply by 0.1761

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    "The guy has told me that there is no noticable difference between R4 and R5"

    There will be a small but noticeable difference in you electricity/gas bill. How noticeable depends on how expensive the electricity/gas is.