Browse Forums Heating, Cooling & Insulation Re: Insulating 7 Start + new house 11Jul 10, 2018 11:51 am We recently finished our own custom build in Canberra, which is performing well so far this winter (we've even had a couple of times where it's actually overheated and we've had to open lots of windows to cool it down). Part of our brief was to be highly energy-efficient while only using readily available (and affordable) materials and methods, and going for the best bang-for-buck (e.g. not going overboard to chase those last few percentage points of efficiency). Our stud walls have R2.7 batt insulation - yes, batt insulation in stud walls isn't perfect, and shouldn't be relied upon as your only insulation layer, but it still definitely helps, and is one of the cheapest things you can do. The thermal bridging of the studs does mean that you need a second layer, though - for us, that's the 75mm EPS external cladding (NRG Greenboard cavity system, specifically). Windows are double-glazed uPVC with U-values of around 1.6-1.8 from a local supplier. Our roof batts are R7.0 (the same caveats apply with roof insulation batts as with walls - it's not perfect and you'll have thermal bridging, but it's cheap and easy and still helps a lot), with an additional layer of R1.5 under the Colorbond roof. Slab bottom and sides are also insulated with 50mm XPS. I strongly recommend (at least) slab-edge insulation in Canberra - it makes a noticeable difference. It's quite nice to be able to comfortably walk bare-footed on tiles in winter. We also have a layer of vapour-permeable airtight building wrap (Bradford Proctorwrap) around the outside of the frame to minimise air leakage (no point in having good insulation if all your warm air just leaks out of the house - airtightness is one area where Australian houses are well behind international practice, and it makes a significant difference to both comfort and energy efficiency). We didn't go for Passivhaus levels of airtightness, but neither did we want the typical Australian leaky sieve. The Colorbond roof also helps with airtightness, as do some of the internal finishes (e.g. square set windows and ceilings have much less air leakage than architraves and cornices). Most importantly, the house was designed with correct passive-solar orientation in mind, capturing a lot of direct Northern sunlight into the living areas, and minimising poorly-oriented windows (with compromises - for example, we have more westerly windows than ideal, in order to capture good westerly views). The end result is a very energy efficient and comfortable house. Despite the larger size of the house, the official 'approval' energy rating was 7.3 stars - and that was before the windows were upgraded to uPVC, the roof insulation was upgraded from R6.0 batts to R7.0 plus R1.5 sislation, and the airtightness wrap and slab insulation were added - the 'as built' energy rating is closer to 8 stars (and we still haven't added window coverings yet). We could've done more, but we're at the point where doing anything further starts to cost quite a lot while improving performance only marginally. We feel that what we've done is well worth it for bang-for-the-buck; not only are our energy costs very low, but the house is much more comfortable to live in than most others (t-shirt weather inside during a Canberra winter with only minimal heating, while our poor neighbours are running their heating constantly and still have to rug up inside). Cost-wise, the uPVC windows were the big-ticket item, adding about $12K over the quotes for 'standard' windows (you can see our build thread for how many windows we have). The airtightness wrap was only around $4K installed (including taping, although we didn't tape all the penetrations - again, bang-for-buck). The slab insulation was $3K - and in hindsight, I'd probably double it (100mm), especially around the slab edges. The EPS cladding was a little more expensive than bare brick veneer (although bricklaying prices are increasing), but cheaper than rendered brick - again, in hindsight, I'd consider increasing it to 100mm. The cost of upgrading the wall and ceiling batts was less than $2K. If a cost compromise was needed, it'd be the windows - double-glazed (but still thermally-broken) frames from a major supplier would be cheaper, if slightly less effective. We wanted the better uPVC windows due to the amount of glazing we have, and we really love the tilt-and-turn mechanism - if you're not wedded to tilt-and-turn, and for a smaller house with fewer windows, the upgrade would be less attractive. So, yes, you can readily achieve 7-8 star energy ratings in Canberra without breaking the bank, and without using any 'exotic' materials or construction techniques. But reiterating arcadelt's advice - start with the design first. Correct orientation and layout (yourhome.gov.au is a very useful resource) is actually a very significant factor, and (if done correctly) shouldn't cost you a cent. Re: Insulating 7 Start + new house 12Jul 10, 2018 2:14 pm algernon We recently finished our own custom build in Canberra, which is performing well so far this winter (we've even had a couple of times where it's actually overheated and we've had to open lots of windows to cool it down). Part of our brief was to be highly energy-efficient while only using readily available (and affordable) materials and methods, and going for the best bang-for-buck (e.g. not going overboard to chase those last few percentage points of efficiency). Our stud walls have R2.7 batt insulation - yes, batt insulation in stud walls isn't perfect, and shouldn't be relied upon as your only insulation layer, but it still definitely helps, and is one of the cheapest things you can do. The thermal bridging of the studs does mean that you need a second layer, though - for us, that's the 75mm EPS external cladding (NRG Greenboard cavity system, specifically). Windows are double-glazed uPVC with U-values of around 1.6-1.8 from a local supplier. Our roof batts are R7.0 (the same caveats apply with roof insulation batts as with walls - it's not perfect and you'll have thermal bridging, but it's cheap and easy and still helps a lot), with an additional layer of R1.5 under the Colorbond roof. Slab bottom and sides are also insulated with 50mm XPS. I strongly recommend (at least) slab-edge insulation in Canberra - it makes a noticeable difference. It's quite nice to be able to comfortably walk bare-footed on tiles in winter. We also have a layer of vapour-permeable airtight building wrap (Bradford Proctorwrap) around the outside of the frame to minimise air leakage (no point in having good insulation if all your warm air just leaks out of the house - airtightness is one area where Australian houses are well behind international practice, and it makes a significant difference to both comfort and energy efficiency). We didn't go for Passivhaus levels of airtightness, but neither did we want the typical Australian leaky sieve. The Colorbond roof also helps with airtightness, as do some of the internal finishes (e.g. square set windows and ceilings have much less air leakage than architraves and cornices). Most importantly, the house was designed with correct passive-solar orientation in mind, capturing a lot of direct Northern sunlight into the living areas, and minimising poorly-oriented windows (with compromises - for example, we have more westerly windows than ideal, in order to capture good westerly views). The end result is a very energy efficient and comfortable house. Despite the larger size of the house, the official 'approval' energy rating was 7.3 stars - and that was before the windows were upgraded to uPVC, the roof insulation was upgraded from R6.0 batts to R7.0 plus R1.5 sislation, and the airtightness wrap and slab insulation were added - the 'as built' energy rating is closer to 8 stars (and we still haven't added window coverings yet). We could've done more, but we're at the point where doing anything further starts to cost quite a lot while improving performance only marginally. We feel that what we've done is well worth it for bang-for-the-buck; not only are our energy costs very low, but the house is much more comfortable to live in than most others (t-shirt weather inside during a Canberra winter with only minimal heating, while our poor neighbours are running their heating constantly and still have to rug up inside). Cost-wise, the uPVC windows were the big-ticket item, adding about $12K over the quotes for 'standard' windows (you can see our build thread for how many windows we have). The airtightness wrap was only around $4K installed (including taping, although we didn't tape all the penetrations - again, bang-for-buck). The slab insulation was $3K - and in hindsight, I'd probably double it (100mm), especially around the slab edges. The EPS cladding was a little more expensive than bare brick veneer (although bricklaying prices are increasing), but cheaper than rendered brick - again, in hindsight, I'd consider increasing it to 100mm. The cost of upgrading the wall and ceiling batts was less than $2K. If a cost compromise was needed, it'd be the windows - double-glazed (but still thermally-broken) frames from a major supplier would be cheaper, if slightly less effective. We wanted the better uPVC windows due to the amount of glazing we have, and we really love the tilt-and-turn mechanism - if you're not wedded to tilt-and-turn, and for a smaller house with fewer windows, the upgrade would be less attractive. So, yes, you can readily achieve 7-8 star energy ratings in Canberra without breaking the bank, and without using any 'exotic' materials or construction techniques. But reiterating arcadelt's advice - start with the design first. Correct orientation and layout (yourhome.gov.au is a very useful resource) is actually a very significant factor, and (if done correctly) shouldn't cost you a cent. Re: Insulating 7 Start + new house 13Jul 11, 2018 11:04 pm Any chance you can explain further why you opted to use this product? Speed of construction? Re: Insulating 7 Start + new house 14Jul 11, 2018 11:28 pm Searching4 knowledge algernon I'm going to build b/veneer in Sydney Also did you happen to get a power square metre rate to build the wall? Re: Insulating 7 Start + new house 15Jul 12, 2018 1:50 pm alexp79 E.g. I am ordering R1.5 windows (U value of <R0.7) to my house, which will work quite well with my consistent R2.8 wall insulation (without thermal bridging). alexp79 can you share where your windows are coming from, i.e brand and through whom did you order from? Re: Insulating 7 Start + new house 16Jul 12, 2018 8:04 pm MisterSlope alexp79 E.g. I am ordering R1.5 windows (U value of <R0.7) to my house, which will work quite well with my consistent R2.8 wall insulation (without thermal bridging). alexp79 can you share where your windows are coming from, i.e brand and through whom did you order from? I am ordering Austrian Internorm windows from local distributor (PM me for the details) - tripple glazed KF500 secure profile, alum + PVC, U = 0.67 on average. Quite expensive - costs me approx. A$1.3K per sqm of glazing, but I believe it is really worth it, considering 10 year warranty, quality of the hardware and glazing, etc. You can also consider German Dopfner windows from Laros: http://windows.laros.com.au/, they are a bit cheaper and they have timber + alum options, while U is a bit higher (0.8+). Re: Insulating 7 Start + new house 17Jul 12, 2018 9:19 pm alexp79 MisterSlope alexp79 E.g. I am ordering R1.5 windows (U value of <R0.7) to my house, which will work quite well with my consistent R2.8 wall insulation (without thermal bridging). alexp79 can you share where your windows are coming from, i.e brand and through whom did you order from? I am ordering Austrian Internorm windows from local distributor (PM me for the details) - tripple glazed KF500 secure profile, alum + PVC, U = 0.67 on average. Quite expensive - costs me approx. A$1.3K per sqm of glazing, but I believe it is really worth it, considering 10 year warranty, quality of the hardware and glazing, etc. You can also consider German Dopfner windows from Laros: http://windows.laros.com.au/, they are a bit cheaper and they have timber + alum options, while U is a bit higher (0.8+). Thanks for the reply. Will drop you a PM shortly. A$1.3K per sqm is reasonable considering it is triple glazed. Additionally Vitrocsa is about A$2.5K per sqm but that is the premium end of windows. Re: Insulating 7 Start + new house 18Aug 11, 2018 6:56 pm alexp79 MisterSlope alexp79 E.g. I am ordering R1.5 windows (U value of <R0.7) to my house, which will work quite well with my consistent R2.8 wall insulation (without thermal bridging). alexp79 can you share where your windows are coming from, i.e brand and through whom did you order from? I am ordering Austrian Internorm windows from local distributor (PM me for the details) - tripple glazed KF500 secure profile, alum + PVC, U = 0.67 on average. Quite expensive - costs me approx. A$1.3K per sqm of glazing, but I believe it is really worth it, considering 10 year warranty, quality of the hardware and glazing, etc. You can also consider German Dopfner windows from Laros: http://windows.laros.com.au/, they are a bit cheaper and they have timber + alum options, while U is a bit higher (0.8+). Be very careful comparing European U-Values, and Australian ones (ie WERS compliant). They are different, with the same window getting a lower rating in Europe than here (Europe assumes a larger window than Aus/US for the test, and so frames are proportionally smaller, and thus contribute less losses) - see http://www.paarhammer.com.au/blog/u-val ... australian Also, when comparing other overseas markets, places like NZ often lists the glazing U value, not the glazing/frame U value (at least in marketing materials) Re: Insulating 7 Start + new house 19Aug 11, 2018 7:32 pm planeguy Be very careful comparing European U-Values, and Australian ones (ie WERS compliant). They are different, with the same window getting a lower rating in Europe than here (Europe assumes a larger window than Aus/US for the test, and so frames are proportionally smaller, and thus contribute less losses) - see http://www.paarhammer.com.au/blog/u-val ... australian Also, when comparing other overseas markets, places like NZ often lists the glazing U value, not the glazing/frame U value (at least in marketing materials) I agree, the difference will be there, but it won't be that significant. E.g. for a frame width of 80 mm, the Australian test window will have only around 7% of more frame when comparing to European test window. For each window, I have U values provided for both glazing and frame+glazing. Re: Insulating 7 Start + new house 20Aug 12, 2018 6:35 pm alexp79 planeguy Be very careful comparing European U-Values, and Australian ones (ie WERS compliant). They are different, with the same window getting a lower rating in Europe than here (Europe assumes a larger window than Aus/US for the test, and so frames are proportionally smaller, and thus contribute less losses) - see http://www.paarhammer.com.au/blog/u-val ... australian Also, when comparing other overseas markets, places like NZ often lists the glazing U value, not the glazing/frame U value (at least in marketing materials) I agree, the difference will be there, but it won't be that significant. E.g. for a frame width of 80 mm, the Australian test window will have only around 7% of more frame when comparing to European test window. For each window, I have U values provided for both glazing and frame+glazing. Not sure where your 7% comes from. Using your assumption of an 80mm frame, the Aus window (by area) is 66% glass, 34% frame. The European window is 78% glass, 22% frame. Now assuming the glass part is like some figures I have found for NZ triple glazed 46mm units (R1.81) that shows the frame is weak spot. Now I am not saying your window choice isn't fantastic, but just be careful not to make a direct comparison of U value when they are not directly comparable. Yes well there solution is to blame everyone else while I a 65yr old woman with major medical problems have to just continue to boil water and wash myself in a bucket… 2 16019 If you make sure all taps inside and out are turned off, what does the water meter show if you leave it for a while. 2 20235 13 6632 |