Browse Forums Heating, Cooling & Insulation 1 Nov 11, 2010 5:07 pm I live in the North West of Sydney (Hills Shire Council). I'm looking at getting insulation put into the roof as there is currently nothing except the sarking we had put in early this year. From my reading it seems the recommended minimum for Sydney is R3.5. Apart from the price, is there any reason why I wouldn't put R6 batts in? I've had the following quotes for earthwool: R 3.5 $1,300.00 plus GST R 4.0 $1,625.00 plus GST R 6.0 $2,340.00 plus GST Polyester: R 3.5 $1,690.00 plus GST R 4.0 $2,080.00 plus GST Wool: R3.5 $5,130.00 plus GST The roof is around 130sqm. Re: Which R value insulation for Sydney? 2Nov 11, 2010 5:39 pm Insulation gives you diminishing returns as you increase it. The first R2 are the most signifiant. After that it get's less important. Anything over R4 is pretty well a waste of money and space. Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: Which R value insulation for Sydney? 4Nov 11, 2010 8:29 pm We have R4 and sarking and it's not good enough (ie. as much as I expected that combo to work). Still have to check if they indeed put the batts everywhere with no gaps . My signature is distracting people from my wise posts ... Re: Which R value insulation for Sydney? 5Nov 11, 2010 9:04 pm R6 would be great, all round. Unfortunately windows have an R rating of about 0.2, so no matter how good you make your wall and ceiling insulation, the windows will let you down. That is why after R4, you get very little benefit. Now, if you had a windowless room ... Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: Which R value insulation for Sydney? 6Nov 11, 2010 9:08 pm Anyway, good point. I'm waiting for some blinds to be installed on 2 small windows on the west - I do expect big difference. Currently we just close the doors and the difference is huge Although, I am tempted to beef up the R in the roof anyway ... My signature is distracting people from my wise posts ... Re: Which R value insulation for Sydney? 7Nov 12, 2010 4:56 pm Casa2 R6 would be great, all round. Unfortunately windows have an R rating of about 0.2, so no matter how good you make your wall and ceiling insulation, the windows will let you down. That is why after R4, you get very little benefit. Now, if you had a windowless room ... Yup.. I know what you mean. We've recently replaced a north facing sliding door, window and hollow core door with some double glazed UPVC units that have 6.38mm tinted laminated glass, air gap and then clear 6.38mm laminated glass. Re: Which R value insulation for Sydney? 12Dec 17, 2010 4:47 pm Casa2 Insulation gives you diminishing returns as you increase it. The first R2 are the most signifiant. After that it get's less important. Anything over R4 is pretty well a waste of money and space. You are correct for the Sydney climate in particular. I normally get good simulation results with R3.5 and I have not used more in Sydney area to get a high star rating in my assessments. Extra money for higher performance insulation can be directed to more efficacious provisions like smart shading and better windows. Manuel Basiri Re: Which R value insulation for Sydney? 13Dec 17, 2010 5:01 pm asterix79 I thought the R value was roughly the amount of hours it took for the heat/cold to penetrate the insulation, so an R6 would mean it would keep the heat out for 6 hours. This is not correct. R Value is the thermal resistance of one square meter of a particular substance to prevent heat transfer thorough it as the results of the temperature difference in both sides. The metric unit of R Value is m2.K/W. Higher R values mean less heat is transfered through one square meter of the material for each degree of temperature difference in both sides per unit of time. In the metric system, the R value measures per meter squared the amount of degrees kelvin temperature difference required to transfer one watt of energy through the material. So an R value of 1 means a single degree difference will transfer one watt of energy through 1 square meter of the material. So an R value of 2 will transfer half a watt of energy for 1 degree of temperature difference or requires 2 degrees of temperature difference for 1 watt heat transfer and so on. Manuel Basiri Re: Which R value insulation for Sydney? 15Jan 07, 2011 6:55 pm Thudd Interestingly, when I priced batts locally just recently, because of the batt size and number of batts per pack the R6 batts ended up virtually the same price as the R4. But much thicker (with very little benefit). Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: Which R value insulation for Sydney? 16Jan 07, 2011 8:07 pm Bear in mind how they measured the floor area. If they have measured around the external part of your house they will need less batts thn actually required. Years and years ago I installed batts and found that you can get away with 10% less than measured when you add up the width of the ceiling joists it adds up - especially at 450mm centres and even 600mm given the batts fit in between them (not over) Just a thought Might be a bargaining tool? You get what you pay for! Which chrome tapwares is a good affordable brand with a good warranty in Myhomeware shop Sydney. I visited the shop and they… 0 2178 As a tradesmen get a private inspector although I don't think there worth it in their profession themselves the reminder they serve to the tradesmen doing the work is… 3 27359 They make the room much easier to clean for one, reflect more light (if light colour tiles are used), and you dont end up with dust on the top edge of tiles (cause most… 3 9592 |