Browse Forums Building A New House 1 Jun 14, 2009 9:26 am Hi all i have been thinking about this R batt (wall insulation), and i have little knowledge about this. i was hoping if someone can give me some light to make me understand. i want to build with builder A, they have R1.5 foil wrap external walls, ceiling, R3.5 therma blow. i saw other builder, use R2.5 external walls...R3.5 therma blow. would using R1.5 and R2.5 make any huge difference ? it seems, builder A, using insulation for 5 star rating house (just on the border line), which translates, if you make slight changes, it will make your rating into 4 stars. i am afraid, if i build with builder A design, which it's certain that i would make some changes, in the end they will ask me to put some more money to bring it back to 5 stars. is that how it work ? or is it better to pay more for R2.5, so at least my house can have a good energy rating ? does anyone know how much it cost ? thanks in advance guys Final stage Re: R batt (insulation) 2Jun 14, 2009 9:42 am Yes be careful with changes when you are looking at energy ratings - but on another note: - If your total floor area is say 100 m2 and your total wall area is say 100 m2. Assuming a temperature difference between outside and inside of say 10 degrees. Then
R2.5 walls or ceiling will cost you 6.8 kWh a day to run But on the same day, for those who think glazing doesn't matter too much in the home energy equation...
You can prorata the results for your house... Ed "ECOECO" At 'EcoEco', we design windows, we design the best windows, we do it for you, so that when you’re happy we are happy. Tel. 1800 326 326 Re: R batt (insulation) 3Jun 14, 2009 11:08 am thanks ed. it seems, i am start thinking maybe as a rule of thumb, we can make a graph, of how the R, window, and cost can play a role. therefore people can get idea of, "what's the best bang for the buck". what d'ya think? price is always changing, at least, we can assume price at that time, Energy rating at that time... just to give people ideas. Final stage Re: R batt (insulation) 4Jun 14, 2009 12:45 pm It is a minor cost now with major benefits to have later. ie A lot harder to retro fit a wall in 3 years time because you do not have enough in there. Melbourne should have higher levels than that in the walls. read more here about recommneded minimums for your area. http://www.yourhome.gov.au/technical/fs47.html#levels Re: R batt (insulation) 5Jun 14, 2009 1:58 pm d3p thanks ed. it seems, i am start thinking maybe as a rule of thumb, we can make a graph, of how the R, window, and cost can play a role. therefore people can get idea of, "what's the best bang for the buck". what d'ya think? price is always changing, at least, we can assume price at that time, Energy rating at that time... just to give people ideas. I agree 100%, as a priority make the changes that give you the best overall result, then secondary make it work in FirstRate software or whatever. Yes, good idea, you can graph the information and optimise your home in your graph... it's straighforward arithmetic. And I am sure someone will come on and say what about draughts - but you would need to look after that in any case... and it's not really looked after in the software. Ed "ECOECO" At 'EcoEco', we design windows, we design the best windows, we do it for you, so that when you’re happy we are happy. Tel. 1800 326 326 Re: R batt (insulation) 6Jun 14, 2009 6:47 pm thanks Yak_Chat for pointing that one out. what if builder is offering package less than that website suggested? is there any regulation from government to "force" builder meeting the minimum requirement? i.e in this case, Melbourne is roof 3.7, wall 2.2 most builder will offer roof 2.5, wall 1.5, or roof 3.5, wall 1.5 what i ve been thinking off, once you change this change that (minor change), that's when builder can blame you, because you change this and that, you no longer meet 5 star rating requirement. IN FACT, originally their design doesn't meet the requirement anyway.... there should be a law ? maybe builder has been using this proportion Roof R2.5, wall R1.5, from 5 years ago, when climate isn't this extreme. They should update their database ! Yak_Chat It is a minor cost now with major benefits to have later. ie A lot harder to retro fit a wall in 3 years time because you do not have enough in there. Melbourne should have higher levels than that in the walls. read more here about recommneded minimums for your area. http://www.yourhome.gov.au/technical/fs47.html#levels Final stage Re: R batt (insulation) 7Jun 14, 2009 7:46 pm It's all theoretical calculations. Adding more insulation to your walls and ceiling are definiately going to help increase your rating. and the builder would have nothing to come back becasue you upgraded that. Removing windows helps heaps too. So if you took out all of your western windows you'd fly through to 6 or maybe 7 stars But it would be a bit dark in there. So it's all a compromise to achieve the best you can. The people who run the figures are not allowed to advise on what to do to make the house better - (the law) So they hint at where to look at changing things - then the designer or builder has to think - hmm what can I do that will help - then resubmit. I know of houses that could never meet 5 star via the computer simulations - so they get an exemption via seperate anaylsis. Yet these same houses are 19 to 20 degrees inside on days like today - and they have not turned on their heating this winter at all - with 13 degree days. Such are the benefits of a well designed thermally efficient and sun catching house, double glazing, r5.4 insulation and good design to get the sun where you need it, no sun where you do not. Cost of the house - about the same as you are intending to pay I'd guess. Re: R batt (insulation) 8Jun 14, 2009 8:32 pm our builder uses 2.5 in walls and 3.5 in roof is this enough? Should we have double glazed windows? what is the extra cost? thanks www.buildingwithwisdomhomes.blogspot.com Re: R batt (insulation) 9Jun 14, 2009 9:07 pm 1sttimer our builder uses 2.5 in walls and 3.5 in roof is this enough? Should we have double glazed windows? what is the extra cost? thanks http://www.buildingwithwisdomhomes.blogspot.com are you sure he uses 2.5 in the wall. Is it possible that he adding the foil say 1 plus 1.5 batts. The issue here would be you cant add R ratings. it doesnt work like that. Re: R batt (insulation) 10Jun 14, 2009 9:11 pm house not build just saying what is in the contact. just doubled check it is 2.0 in walls borg 1sttimer our builder uses 2.5 in walls and 3.5 in roof is this enough? Should we have double glazed windows? what is the extra cost? thanks http://www.buildingwithwisdomhomes.blogspot.com are you sure he uses 2.5 in the wall. Is it possible that he adding the foil say 1 plus 1.5 batts. The issue here would be you cant add R ratings. it doesnt work like that. Re: R batt (insulation) 11Jun 14, 2009 9:32 pm borg The issue here would be you cant add R ratings. it doesnt work like that. It's not precise - but it's pretty close... http://www.sizes.com/units/rvalue.htm "ECOECO" At 'EcoEco', we design windows, we design the best windows, we do it for you, so that when you’re happy we are happy. Tel. 1800 326 326 Re: R batt (insulation) 12Jun 17, 2009 9:10 pm yak chat so from what you saying, i can draw rule to achieve energy rating, one of them will be : windows on south, west, need to be as small as possible, and as few as possible (balancing the light) on north, make it as big as possible (balancing with security of course) east, standard window does it mean, i need to have better R rating wall on the west side, as that's where the hottest part is ? also, i can draw conclusion that builder mostly offering R batt wall that lower than what gov suggest ? i wonder why? "The people who run the figures are not allowed to advise on what to do to make the house better - (the law) ?" isn't it better, if they can provide what they should have, give people chance to learn and have better rating, rather than spending 20-25 k just because they didn't meet the energy rating?? and w'all have better world Yak_Chat It's all theoretical calculations. Adding more insulation to your walls and ceiling are definiately going to help increase your rating. and the builder would have nothing to come back becasue you upgraded that. Removing windows helps heaps too. So if you took out all of your western windows you'd fly through to 6 or maybe 7 stars But it would be a bit dark in there. So it's all a compromise to achieve the best you can. The people who run the figures are not allowed to advise on what to do to make the house better - (the law) So they hint at where to look at changing things - then the designer or builder has to think - hmm what can I do that will help - then resubmit. I know of houses that could never meet 5 star via the computer simulations - so they get an exemption via seperate anaylsis. Yet these same houses are 19 to 20 degrees inside on days like today - and they have not turned on their heating this winter at all - with 13 degree days. Such are the benefits of a well designed thermally efficient and sun catching house, double glazing, r5.4 insulation and good design to get the sun where you need it, no sun where you do not. Cost of the house - about the same as you are intending to pay I'd guess. Final stage Hey guys building a new place through a volume builder and just wondering if i should complain to the site supervisor as we just had plasterboard installed. Looks like… 0 11827 1000000% definitely add insulation. I have in my home and it makes a big difference minimising sound transfer. Insulation is pretty cheap and definitely worth it 2 6779 |