Insulation - much benefit of more than R3.2?

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Disrespective

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#1619766 30-Aug-2016 16:40

Jase2985:

Disrespective: Mammoth do a polyester insulation which will cost you a bit more, but has better r values in the same thickness. It might be worth considering if max r value is important.

no it doesn't. an example, Mammoth 105mm skillion R2.9 vs Earthwool 105mm skillion R3.2. Same deal for the walls. there is about R0.3 difference for the same thickness for the wall sections

It does, but I believe not by the current testing standards. They're looking into getting their products tested differently, but I suspect it will be difficult to test against competitors products without a large cost.

Regardless, I like the mammoth product for it's environmentally friendly reuse of plastic bottles, and dense structure so will never sag over time. Most/all other glass wool products will sag, and even a 5mm gap causes a large reduction in efficiency so minimising sag is particularly important.

Meh. Insulation is insulation most of the time.

mattwnz

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#1619780 30-Aug-2016 17:01

The other problem with polyester (but I stand to be corrected), is that it can't be used to insulate over IC light fittings in ceilings like some glass wool type insulations can. This is especially important with Skillion roofs which often have downlighters.

I quite like the wool/poly blends, and supposedly they have moisture properties, but as far as I am aware they can't be used over IC lights.

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#1619781 30-Aug-2016 17:12

MikeAqua:

Wheelbarrow01:

Architects and quantity surveyors etc tend to specify the brand name GIB on their plans, meaning you must use GIB in those instances where council sign-off is required (i.e. new builds).

That practice ... should be illegal for something as generic as plasterboard.

Should be specified as something like ... plasterboard conforming to standard NZSxxx

I am not sure where you got that info from. When an architect designs a house, they also create a book of specifications, and that is often based on the actual brand of product produced by the manufacturer, it isn't for generic products.

Also they may have used the GIB bracing calculator, which I believe can only be used with GIB products as it has different properties over other products,. Also Architects have their own preferred materials and providers, it is the whole reason people use an architect, as they can recommend products they have experience with over products that they have had bad experiences with.

In terms of gib, I know a developer who initially specified Gib on the plans. When it was being built they decided to use a cheaper product. The council found out and put a stop on the project and they had to get it re engineered. So would be surprised if they didn't save anything from the substitution.

Also if there are in fact NZS standards for plasterboard, all plasterboard in NZ should meet those standards anyway.

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#1619805 30-Aug-2016 18:23

mattwnz:

The other problem with polyester (but I stand to be corrected), is that it can't be used to insulate over IC light fittings in ceilings like some glass wool type insulations can. This is especially important with Skillion roofs which often have downlighters.

We have GreenStuf polyester insulation in some parts of our house, which I believe can be insulated over IC rated downlights. I can't speak for other brands.

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#1619819 30-Aug-2016 19:03

froob:

mattwnz:

The other problem with polyester (but I stand to be corrected), is that it can't be used to insulate over IC light fittings in ceilings like some glass wool type insulations can. This is especially important with Skillion roofs which often have downlighters.

We have GreenStuf polyester insulation in some parts of our house, which I believe can be insulated over IC rated downlights. I can't speak for other brands.

I don't think it does. According to this document, it can be 'abutted'. This usually means to the sides, but it doesn't mention whether it can cover the lights above. It isn't clear though, because it also says that it can be used to temperatures up to 90 degrees, and then it says it can be used up to 150 degrees. Do you have some installed over downlights?

http://www.autexindustries.com/assets/Uploads/documents/GS-NZ-DS-Downlights-The-Facts-Oct13-Web.pdf

If it can be installed over downlighters, it really should specify that fact. For example Bradford Gold does state that it can be abutted, and it also states it can be used to cover IC fittings at http://www.bradfordinsulation.co.nz/downlights/ . I can't see that info on the GS one. I was looking for a solution to this problem a few years ago, and did check with a number of manufacturers on whetehr it could be used to cover IC fittings.

froob

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#1619828 30-Aug-2016 19:34

mattwnz:

I don't think it does. According to this document, it can be abutted to the sides, but it doesn't mention whether it can cover the lights above. Do you have some installed over downlights?

http://www.autexindustries.com/assets/Uploads/documents/GS-NZ-DS-Downlights-The-Facts-Oct13-Web.pdf

Yes, we have a few covered downlights.

I agree that the fact sheet is ironically not very clear. But, it confirms that IC rated downlights can be covered by non-flammable insulation rated stable at 90°C, then goes on to confirm that GreenStuf is classified as non-flammable and stable at 90°C (and 150°C).

Here are a couple of pages that are clearer (from a Google search):

- http://www.forman.co.nz/files/file/1858/MasterSpec+2013+Autex+Thermal+Acoustic.pdf

- http://www.eliteinsulation.co.nz/about-greenstuf/insulation-downlights

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#1619885 30-Aug-2016 20:32

froob:

mattwnz:

I don't think it does. According to this document, it can be abutted to the sides, but it doesn't mention whether it can cover the lights above. Do you have some installed over downlights?

http://www.autexindustries.com/assets/Uploads/documents/GS-NZ-DS-Downlights-The-Facts-Oct13-Web.pdf

Yes, we have a few covered downlights.

I agree that the fact sheet is ironically not very clear. But, it confirms that IC rated downlights can be covered by non-flammable insulation rated stable at 90°C, then goes on to confirm that GreenStuf is classified as non-flammable and stable at 90°C (and 150°C).

Here are a couple of pages that are clearer (from a Google search):

- http://www.forman.co.nz/files/file/1858/MasterSpec+2013+Autex+Thermal+Acoustic.pdf

- http://www.eliteinsulation.co.nz/about-greenstuf/insulation-downlights

Thanks for that, it looks like they have clarified things since the 2013 factsheet was done.
It is interesting because I went through the process several years ago when looking for insulation on a project, and was told by a lighting manufacturer that only fibre glass could be used to cover their IC lights. Part of the problem is that some lights get very hot, as do the components. I wouldn't be surprised if some metal parts got above 150 degrees. I was told by one wool insulation manufacturer that their product could be used for abutting but not for not covering. I can't recall what it was for polyester, although don't think the R values for the product were as good as fibre glass at the time, so may not have investigated it in depth. But there are new and revised products coming out all the time. So will have to check out Polyester again as an option on a new build.

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#1619941 30-Aug-2016 21:38

We've just replaced some old downlights with IC-F LED ones for the express purpose of being able to insulate around and above them.

The spec sheet that came with them ("Switch Lighting" brand) says the following are approved insulation: Pink Batts, Bradford Gold, InsulPro Polyester, Ecofleece, Autex Greenstuff, Earthwool, Premier.

It specifically says macerated paper, insulfluff and other loose fill insulation is definitely not okay, even with an IC-F rated light.

For all other insulation, it seems to quote a standard - for a CA-135 "luminaire" (light?) has to be okay up to 150 degrees, for a IC-F, IC and CA-80 luminaire has to be okay up to 90 degrees. There's also a reference to a 30 second needle flame test.

And now I've just read down to the bottom of the page and there's a website. D'oh! Didn't need to type it out. See http://www.switch-lighting.co.nz/installation-sheets-downloads/. We have the SL40 downlights. They're nice lights too, didn't faff about with the quality on that score.

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#1620345 31-Aug-2016 17:34

Disrespective:

Jase2985:

Disrespective: Mammoth do a polyester insulation which will cost you a bit more, but has better r values in the same thickness. It might be worth considering if max r value is important.

no it doesn't. an example, Mammoth 105mm skillion R2.9 vs Earthwool 105mm skillion R3.2. Same deal for the walls. there is about R0.3 difference for the same thickness for the wall sections

It does, but I believe not by the current testing standards. They're looking into getting their products tested differently, but I suspect it will be difficult to test against competitors products without a large cost.

Regardless, I like the mammoth product for it's environmentally friendly reuse of plastic bottles, and dense structure so will never sag over time. Most/all other glass wool products will sag, and even a 5mm gap causes a large reduction in efficiency so minimising sag is particularly important.

Meh. Insulation is insulation most of the time.

I was comparing insulation R values for 140 thick walls. It appears that the polyester R values are quite a bit lower than the fiberglass equivalents. For example Earthwool is 4.1, Bradford Gold and pickbatts is 4, which are all glasswool, so they are all very similar. While Greenstuff and Mammoth is 2.8, which is quite a drop. But if they don't sag, then they maybe a better option over a longer period of time, as the R value should remain constant.. This is according to the Design Navigator, which should be up to date. Not really sure though which offers the best bang for buck, as contractors seem to have their own preferred manufacturer.

mdf

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#1620418 31-Aug-2016 20:32

mattwnz:
Disrespective:

Jase2985:

Disrespective: Mammoth do a polyester insulation which will cost you a bit more, but has better r values in the same thickness. It might be worth considering if max r value is important.

no it doesn't. an example, Mammoth 105mm skillion R2.9 vs Earthwool 105mm skillion R3.2. Same deal for the walls. there is about R0.3 difference for the same thickness for the wall sections

It does, but I believe not by the current testing standards. They're looking into getting their products tested differently, but I suspect it will be difficult to test against competitors products without a large cost.

Regardless, I like the mammoth product for it's environmentally friendly reuse of plastic bottles, and dense structure so will never sag over time. Most/all other glass wool products will sag, and even a 5mm gap causes a large reduction in efficiency so minimising sag is particularly important.

Meh. Insulation is insulation most of the time.

I was comparing insulation R values for 140 thick walls. It appears that the polyester R values are quite a bit lower than the fiberglass equivalents. For example Earthwool is 4.1, Bradford Gold and pickbatts is 4, which are all glasswool, so they are all very similar. While Greenstuff and Mammoth is 2.8, which is quite a drop. But if they don't sag, then they maybe a better option over a longer period of time, as the R value should remain constant.. This is according to the Design Navigator, which should be up to date. Not really sure though which offers the best bang for buck, as contractors seem to have their own preferred manufacturer.

Anyone ever used PIR boards? I've just been reading up on them having both read this thread and watched Colin Furze use them to make a laptop soapbox derby racer. The marketing material sounds impressive (double the R value for equivalent thickness of glass wool) but I'm picking there's another shoe to drop.

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#1620492 1-Sep-2016 00:08

mattwnz:

I was comparing insulation R values for 140 thick walls. It appears that the polyester R values are quite a bit lower than the fiberglass equivalents. For example Earthwool is 4.1, Bradford Gold and pickbatts is 4, which are all glasswool, so they are all very similar. While Greenstuff and Mammoth is 2.8, which is quite a drop. But if they don't sag, then they maybe a better option over a longer period of time, as the R value should remain constant.. This is according to the Design Navigator, which should be up to date. Not really sure though which offers the best bang for buck, as contractors seem to have their own preferred manufacturer.

This was why I wanted glasswool. Just because it seems to have the best R value Vs thickness ratio. At least for flexible products. Im still going to go ahead with my double layer plan. As there are commercial and industrial buildings with glasswool insulation directly on the underside of the roofing iron. Which is far more risky than what I want to do. As they have trough section roofing on a far lower slope than my roof.

I just want to be warm. Will also put new building paper in the roof as the old stuff is extremely brittle from 45+ years of the sun heating the roof. I will stick a temp sensor under the iron as well - cause I can

@Bung I will still be using my heating system. But the main reason for the insulation is to help keep the inside of my house at a more stable temperature. And there are alot of times where it is cold. But not cold enough to justify starting the boiler. Flick electric has also helped out alot. As off peak power is cheap enough to justify using an electric heater and to boost the hot water cylinder. On the not so cold nights. Flick electric didn't exist when I first built my boiler / radiator system.

And I would need a really high capacity electric heater to heat the spa faster than what the boiler can do.

Will probably get heatpumps eventually. But that will wait until the house is fully insulated. If I get them now they will be either over sized for a fully insulated house. Or undersized for the house in it's current state. And it is extremely unlikely that Natural Gas will get installed in my street. Unless Vector get forced to sell the gas network. As vector have no incentive to extend the gas network as electricity usage will go down.

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Disrespective

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#1620817 1-Sep-2016 12:15

@mdf Yeah i've used the Kingspan stuff before. It's a bit costly, but in the instance we were using it, it included the GIB wall lining too so mitigated the costs there. It very much depends on the application as to whether it's a good option though. The majority of times i've used it, it was used as a lining over concrete block walls in a lower level fwiw. I wouldn't consider it for ceilings or wall insulation where you can use wool insulation purely due to cost.

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#1648008 9-Oct-2016 14:55

The R values do mean something so we can work it out what difference it would make. R3.2 is U0.3125, x 100m2 = 31.25 watts x 10 degrees average difference with roof space = 312.5 watts x 24h = 7500w heat loss per day. The figure for R4, R5 and R6 is 6000w, 4800w and 4000w. There are factors like how cold the region is and whether the rafters are covered but this gives you some idea.

Glass has an R value of around 0.3? So double glazing will be better than 0.6, but nothing like what batts etc. provide.

Glass has an R value of around 0.16. Double glazed glass has a minimum of R0.35 and can go as high as around R0.9 with argon and low-emissivity glass.

Typical double glazed windows in New Zealand are R0.28 with plain glass and thermally unbroken window frames.

Downlights are one area to look at. Even "sealed" units, which may not actually be sealed, can let a crazy amount of heat out unless they're insulated over.

Down lights may be IC-F rated and while the light itself may be sealed that doesn't mean the plastic rim is air tight sealed to the heatsink. The IP rating is more indicative with higher numbers being better. Switch Lighting's new IP65 IC-F units are fully sealed, their old IP44 units were chimneys without some sealant application. Some IC-F rated downlights are rated to have polyester installed over them, check the documentation.

What's the noise level like? Double glazing would help there when heavy curtains aren't appropriate.

Double glazing isn't as inherently effective at reducing noise as people think it is. People think it does because they've gone from an old window with a poor or non existent seal that lets both sound and air through, to a new sealed window. If it's letting in a draught, it's letting in noise. If you want to reduce noise get a sound stopping interlayer inside the glass as that's around two and a half times more effective than glass by itself. There is an acoustically optimal distance for glass panes to be spaced for noise reduction but thick "secondary glazing" may be more expensive than an insulating glazing unit.

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#1648026 9-Oct-2016 15:12

bfginger:
Glass has an R value of around 0.16. Double glazed glass has a minimum of R0.35 and can go as high as around R0.9 with argon and low-emissivity glass.

Typical double glazed windows in New Zealand are R0.28 with plain glass and thermally unbroken window frames.

The important factor with insulating windows is to compare insulating via the glass to other types of insulation/heat-retention. Unless you want to lay out a small fortune for low-e argon-filled glass with thermally broken frames, double glazing barely stacks up against a few hundred dollars for solid thermal drapes with a good seal around the window frame (the good seal is the important part, you don't want the cold glass acting as a convection cooling system). If you're in a location where you get reasonable daytime temps and it only gets cold at night (Orkland would be one example) then you're better off with thermal drapes that you close when it gets dark/cold outside than spending a fortune on new windows.

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