Oh and the house is about 22 squares if that helps.
Double glazing recommendations please
(112 posts) (44 voices)-
TonyT
Memberone kiloWatthour is 3.6MegaJoules
73,000MJ = 73,000 / 3.6 equals 20,300kWh
If this was electricity costing 30cent/kWh it would cost $6,090 per year.one square of floor area is 10 sqm
20,300kWh/220sqm equals 92kWh/sqm per year
If you heat for ? 150days/yr
92/150 is 0.61kWh per dayWhat is the present cost per MJ of gas ?
Posted Monday 7 May 2012 @ 9:56:18 pm from IP # -
ghostgum
MemberNatural gas in south-east Melbourne is 1.8 cents per MJ.
http://www.originenergy.com.au/files/Multinet_Main_1.pdfA more accurate conversion of one square (10 feet by 10 feet) is 9.29 square metres.
From your electricity heating cost, you can see why people use heat pumps, and off-peak. If you can run the heat pump with COP 3, and off-peak (i.e. heat a storage tank for use by hydronics), then you could get the heating cost down to 20300 * 0.125 / 3 = $845.
Gas cost would be 73000 * 0.018 = $1314 plus $200 service fee.With the increases in gas prices, my heating costs are more like $720 gas and $200 service fee. (My previous figures were based on 1.2 cents per MJ from about 4 years ago)
Posted Tuesday 8 May 2012 @ 12:00:42 am from IP # -
TonyT
MemberCost increase for gas: from 1.2 to 1.8cent/MJ.
Cost increase for electricity: from 20 to 30cent/kWh
The charge for the electricity meter has risen from ?$23 to $50 per quarter or to $200/yr.
The very clever heat pump set-up at Mt Best is running with COP of more than 4
http://mtbest.net/heat_pump.htmlPosted Tuesday 8 May 2012 @ 12:46:29 am from IP # -
Hi All,
It is important to understand that good quality double glazed windows provide much more than just savings on your energy bills, they assist in achieving a comfortable living environment in your which means less temperature fluctuations, prevention of condensation, reduction in acoustic penetration and typically due to the hardware utilised much greater security as well as ease of operation.
When considering good quality double glazed windows do not forget they value add to your home. Keep in mind: Windows are an investment for usually more than 50 years – You shouldn't compromise your choice driven by price comparison. Components and craftsmanship can mean a big difference in performance, comfort and necessity of maintenance each year.
As mentioned in several posts, and important performance figure that is overlooked is Air Infiltration (AI) which is a measure of how many Litres of Air per second per metre squared a window/door leaks. These figures are overlooked for energy rating software but are equally as important, for example there is no point of having a low u-value when a window leaks 5 litres of air per second and allows all the energy to escape that way. Generic Windows will achieve an "AI" rating of 5.0, however the use of good seals, and multi-point locking systems that ensure compression along the entire gasket can greatly reduce this. Miglas are able to achieve an AI as low as 0.07.
simplelife said:
Annette started this post with some REALLY scary quotes.. I am hoping that the prices for double glazed window products have come down in the 2 years since this thread began!
We have an old 1955 weatherboard that needs recladding, so we thought we would take the opportunity to also stuff the walls with insulation and replace the windows, most of which don't open any more. So we are now thinking about the window replacement, all of which are on the south side so would benefit from being thermally broken, maintenance free and also glazed to prevent heat loss.
We figured we should get a quote from MIGLAS as they have a window that is timber on the inside and aluminium on the outside.
Does any one have any experience/suggestions in doing something similar? ThanksSimplelife, there are many benefits to a composite system as they provide the interior decor and thermal insulation of a timber window, whilst providing a durable maintenance free aluminium exterior that never needs painting. Our systems external profiles are also designed to mimic the look of a well painted timber window.
There are a couple of other companies that make Composite systems such as Rylock and Stegbar (siteline range)
dymonite69 said:
I think Miglas composite frames are fairly expensive. Alternative install your own wooden reveals to cover the aluminium frames yourself.Dymonite69, our system is on the upper end of the market from a price point of view as you have indicated, but it is reflected in the quality of materials, hardware and attention to detail in our system.
Our system is a little more complicated than just internal reveals for an aesthetic point of view and is actually mainly constructed Victorian Ash. For example in our Door profile, it is 47mm thick - of which 45mm is solid timber.
Thanks,
KurtPosted Wednesday 23 May 2012 @ 4:58:38 am from IP # -
cava
MemberWe are in the process of building our new house on the outskirts of Melbourne, with the excavations already completed. The house is oriented east/west, with large glassed areas to the north to maximise solar gain. All the windows will be double glazed, and the house as a whole suitably insulated on a slab.
The question I am asking is, if the budget allows and we are fortunate to have a small surplus, and we decide to have some windows triple glazed - all things being equal, which would be the best windows to have the triple glazing? ie north, south or east? There are minimal west facing windows.
Personally, I am leaning towards the south facing windows. Any suggestions?
Posted Wednesday 23 May 2012 @ 10:48:04 am from IP # -
cava said:
We are in the process of building our new house on the outskirts of Melbourne, with the excavations already completed. The house is oriented east/west, with large glassed areas to the north to maximise solar gain. All the windows will be double glazed, and the house as a whole suitably insulated on a slab.The question I am asking is, if the budget allows and we are fortunate to have a small surplus, and we decide to have some windows triple glazed - all things being equal, which would be the best windows to have the triple glazing? ie north, south or east? There are minimal west facing windows.
Personally, I am leaning towards the south facing windows. Any suggestions?
Hi Cava,
Well clear glazing, whether it be single, double or triple does not really reduce the amount of solar heat gain. So your judgement should be based upon which room requires the greatest insulation, e.g. the room you will utilise the most would make most sense. E.g. a living room.
Thanks,
KurtPosted Wednesday 23 May 2012 @ 11:11:01 am from IP # -
cava said:
Thanks Kurt. This was my original thinking.No Worries,
I guess the other thing to consider is that the larger windows will also be the weakest points in your building envelope from a thermal insulation point of view so triple glazing them would be effective, however you would most likely be able to opt for more smaller triple glazed windows from a price point if you ignored those larger meaning you can focus on more rooms. Id suggest you really determine which rooms are the most important before coming to any decisions.
Thanks,
KurtPosted Wednesday 23 May 2012 @ 11:54:11 am from IP # -
TonyT
MemberBenefit / Cost calculations can help with making the decisions
e.g.
http://www.ata.org.au/forums/topic/2511#post-27314
You can Google to search this ATA site and read the posts in the many threads that discuss glass, smart glass and double glazing.
My understanding is that for special glazing to be a good financial investment, the room needs to be in use 24/7 and therefore heated 24/7. Also, the cost to provide each kWh of heat must be high.
If a reverse-cycle air conditioner (a heat pump) is used for heating, then the cost per kWh of heat is about 1/3 of the (? 30cent/kWh) cost per kWh of electricity.
This cost/kWh is similar to the cost per kWh of heat from using reticulated gas or from using firewood bought at $320 per tonne to provide about 3,600kWh of heat.Posted Wednesday 23 May 2012 @ 9:06:12 pm from IP # -
Bushwalker
MemberI guess you have to define 'good financial investment' before deciding that double glazing is a bad one.
Generally, houses remain standing for quite a while, and people live a lot of their lives in them. We can price the accumulated energy cost of running heating and cooling in a house over the life of the building and I'd be surprised if the benefits didn't outweigh the costs especially in this time of rising energy prices.
And that's without taking into account the comfort factor Miglas raised, which is real but not measured financially.
In terms of the windows themselves, apart from fixed pane glazing (which is cheap to do in DG anyway), you get what you pay for.
Posted Wednesday 23 May 2012 @ 10:11:29 pm from IP # -
happyhousebuilder
MemberHi all,
We are buying all double glazed, low e, argon filled, uPVC windows for our new home. I have been researching prices and quality in Victoria for a year or so and have narrowed it down to two companies, Nu-Eco or PVC windows, both Melbourne companies who have the frames built in europe. Having lived in Europe uPVC windows seemed the obvious way to go. Prices from these companies were half of Certaineed with same warranty. Biggest shock is the rate of price increases in the past 18 months. Our quotes have gone up about 30% due to changes in building policy, etc.
Wondering if anyone has input into a discussion I recently had. A friend claims that it is a complete waste of money having double glazed windows on north facing windows in Victoria. Have them on the south where the cold winds come from, but just single glazed on the north with heavy curtains and pulmits. Does anyone have any evidence to support this agruement?
Thanks.Posted Saturday 16 Jun 2012 @ 3:35:37 am from IP # -
cava
MemberNot sure about the validity, or otherwise, of only doing partial double glazing. However, I am in a similar position to yourself regarding building and have delayed the start of the process deliberately.
The rational is that the economy is suffering, which is bound to result in a readjustment of pricing downwards. How long this takes is anyone's guess, but hopefully we will see some correction prior to Christmas. Good luck with your build.
Posted Saturday 16 Jun 2012 @ 3:06:14 pm from IP # -
Bushwalker
Memberhappyhousebuilder said:
A friend claims that it is a complete waste of money having double glazed windows on north facing windows in Victoria. Have them on the south where the cold winds come from, but just single glazed on the north with heavy curtains and pulmits. Does anyone have any evidence to support this agruement?
Thanks.Well, for starters, what evidence did your friend offer?
Think of double glazing as insulated windows. If it's significantly colder outside than in, they are going to help regardless of which direction they face.
Single pane windows are the problem from an insulation point of view. Pelmets and heavy curtains are a method of dealing with the problem and so is double glazing. The benefit of double glazing is that you can open the drapes when it is cold outside without trashing your thermal insulation.
BW
Posted Sunday 17 Jun 2012 @ 2:22:50 am from IP # -
ghostgum
MemberUsing double glazing reduces the heat you gain from the sun by about 10% for plain glass (i.e. SHGC is 10% less). If you have low-E glass you lose more than that.
On the other hand, double glazing should halve your heat loss through the windows for the other 16 hours of the day during winter (assuming no curtains), so overall I think you are probably ahead using double glazing on North windows.
Posted Sunday 17 Jun 2012 @ 5:32:24 am from IP # -
happyhousebuilder said:
Wondering if anyone has input into a discussion I recently had. A friend claims that it is a complete waste of money having double glazed windows on north facing windows in Victoria. Have them on the south where the cold winds come from, but just single glazed on the north with heavy curtains and pulmits. Does anyone have any evidence to support this agruement?
Thanks.Funnily enough we do come across this comment occasionaly,
As Bushwalker and Ghostgum have both said the reduction in SHGC (Solar Heat Gain) Between Single Glazing and Double glazing is almost negligible and the insulation improvements far out way any negative impact. For Example Glass only U-values & SHGC BelowSingle Glazing Clear U Value 5.9 & SHGC 0.85
Double Glazing Clear U Value 2.6 & SHGC 0.75
Double Glazing LowE U Value 1.6 & SHGC 0.65Clear Single Glazing to Double Glazed LowE provides a ~73% reduction in U-Value whilst only ~24% reduction in SHGC. Obviously Framing construction, hardware, and sealing play a vital role in overall performance which these figures do not demonstrate.
Double Glazing is not an effective solution for preventing Solar Heat Gain, and even Solar Control coatings are not as effective as good Passive Solar Design (e.g. strategically placed deciduous trees)
As for +30% Price increases, i can't comment for other companies but not sure why that would be the case. Most uPVC systems are imported profiles (good ones typically from Europe), and with how strong The Australian Dollar there must be other factors at play.
Thanks,
KurtPosted Tuesday 19 Jun 2012 @ 12:00:45 am from IP # -
happyhousebuilder
MemberThanks for all the replies and I agree with your arguements, the discussion made no sense. But when people are adament you do start to doubt your own ideas. Another query.
We have designed the house so the sun heats the concrete slab in winter, but house is shaded in summer. From the previous posts I gather having LowE glass can cut the amount of sun heating the slab in winter. What is the benefit of having the low E glass if the sun is not shining on the windows in the heat of the summer and may decrease the amount of sun getting to the slab in winter? Do the better Uvalues make up for it?
Thanks,
MargPosted Thursday 21 Jun 2012 @ 12:30:46 am from IP # -
ghostgum
MemberThe low E coating helps reflect inside heat back inside, keeping the house warmer in Winter. What I have read is that low E glass is best put on the windows that don't get solar gain in Winter, so you would use low E on the east, south and west windows, but not on the north windows. Use external shading methods for the north windows in summer.
Posted Thursday 21 Jun 2012 @ 1:04:00 am from IP # -
happyhousebuilder said:
Thanks for all the replies and I agree with your arguements, the discussion made no sense. But when people are adament you do start to doubt your own ideas. Another query.
We have designed the house so the sun heats the concrete slab in winter, but house is shaded in summer. From the previous posts I gather having LowE glass can cut the amount of sun heating the slab in winter. What is the benefit of having the low E glass if the sun is not shining on the windows in the heat of the summer and may decrease the amount of sun getting to the slab in winter? Do the better Uvalues make up for it?
Thanks,
Margghostgum said:
The low E coating helps reflect inside heat back inside, keeping the house warmer in Winter. What I have read is that low E glass is best put on the windows that don't get solar gain in Winter, so you would use low E on the east, south and west windows, but not on the north windows. Use external shading methods for the north windows in summer.Standard LowE does not significantly affect SHGC as mentioned previously, so i would suggest it is still worthwhile on North Facing Windows.
If Solar Heat Gain is a concern you're better off looking at "SolarE" (SolTech) style coatings on the other elevations and leaving the North just standard LowE.
Thanks,
KurtPosted Thursday 21 Jun 2012 @ 4:45:12 am from IP # -
Kiwi-bird
MemberRightly or wrongly,after a lot of research, we have decided what we want in the way of double glazing to upgrade our home. The problem we're having is finding it. So if anyone knows who can supply the following, or very close to it, I'd appreciate your post:
1. Aluminium frames - preferably thermal break but would consider non-broken but not improved.
2. 23-24mm spacing - either 4/16/4 or 4/16/3. No gas.
3. Side opening, possibly sliding. Not tilt-and turn.
4. Sliding or french doors and potentially non-standard frames for floor-to-ceiling bay windows. (not sure about that but house is 15-years-old now).
We don't need a perfect u rating, we live in coastal Vic. Our choice is based mainly on sound reduction and aesthetic requirements.
Thanks!
Posted Thursday 19 Jul 2012 @ 11:56:49 am from IP # -
Bushwalker
MemberKiwi Bird,
Interesting choices. What is the budget?
Getting sliders to seal is a real challenge. Do you get wind where you are in coastal vic?
Posted Friday 20 Jul 2012 @ 11:58:59 am from IP # -
Kiwi-bird
MemberOoooh yes. The wind comes in off the sea from the North (the side we are wanting to double glaze)... and we're elevated.
I am happy to consider French doors. We have sliding windows on that side now (and a sliding door) and don't get a draught or whistle through them. The lack of a good seal would only bother me if it deteriorated the sound reduction qualities too much.
We do want to use fly screens though and they work well now, sitting on the outside of sliding windows. Not sure how other types of openings work... We only open on that side for breeze at night (when the road quietens down), so they need to work for that...
Really don't like the bulky look of UPVC and it would look wrong on our house and not match the back. Although it's a bummer that the busy road is on the sunny side, the 'cold' side doesn't bother us... it's lovely in winter (we use aircon maybe twice a summer) and we are planning to go solar to deal with our winter heating bills anyway.
I'm wanting the bigger air gap because this is pretty much about sound, and the aluminium is to keep design integrity. Any thermal improvement will be an overall benefit, but not otherwise needed as that side is toasty anyway.
That's why I'm not sure about whether we really need thermal break or not. I can't find any discussions on how frames perform sound-wise, so don't what to throw money away for a thermal benefit we don't need if it wont kill more sound as well.
As for the non-standard bay windows, they are straight-forward rectangles, but I just don't know whether they would be off-the-shelf dims these days.
Posted Saturday 21 Jul 2012 @ 3:21:48 am from IP # -
Kiwi-bird said:
Ooooh yes. The wind comes in off the sea from the North (the side we are wanting to double glaze)... and we're elevated.I am happy to consider French doors. We have sliding windows on that side now (and a sliding door) and don't get a draught or whistle through them. The lack of a good seal would only bother me if it deteriorated the sound reduction qualities too much.
We do want to use fly screens though and they work well now, sitting on the outside of sliding windows. Not sure how other types of openings work... We only open on that side for breeze at night (when the road quietens down), so they need to work for that...
Really don't like the bulky look of UPVC and it would look wrong on our house and not match the back. Although it's a bummer that the busy road is on the sunny side, the 'cold' side doesn't bother us... it's lovely in winter (we use aircon maybe twice a summer) and we are planning to go solar to deal with our winter heating bills anyway.
I'm wanting the bigger air gap because this is pretty much about sound, and the aluminium is to keep design integrity. Any thermal improvement will be an overall benefit, but not otherwise needed as that side is toasty anyway.
That's why I'm not sure about whether we really need thermal break or not. I can't find any discussions on how frames perform sound-wise, so don't what to throw money away for a thermal benefit we don't need if it wont kill more sound as well.
As for the non-standard bay windows, they are straight-forward rectangles, but I just don't know whether they would be off-the-shelf dims these days.
Hi Kiwi-bird,
As bushwalker suggested i would steer clear of Sliders (if possible) as they are difficult to seal. How well a window seals is an Integral part of how well it performs thermally, as well as acoustically. I have mentioned Air Infiltration (AI) earlier on in this thread, but that is a performance measure of how well a window seals (i.e. how much air it allows through) so a lower number is better. A generic window will achieve an AI of 5.0 (and a sliding window won't be far off) whereas systems like casements, and awnings can get much lower. Sliding doors typically seal better (than windows) as the hardware is more developed.
A 22-24mm spacing won't improve acoustic performance that dramatically but it will allow you to utilise acoustic glazing whilst achieving an optimal air space for thermal efficiency (e.g. 8.5 Hush / 12 / 4).
Have you considered a composite system (like ours) These provide the thermal efficiency of a timber window, whilst the aluminium exterior eliminates any maintenance issues as you have indicated you want to keep design integrity.
Our system provides a U-value of approx. 2.6, which can be reduced with Low E glazing, and AI ratings as low as 0.07In relation to Acoustics of a regular aluminium system i would suggest a thermally broken aluminium window would provide higher acoustic insulation than a standard aluminium window.
Thanks,
KurtPosted Monday 30 Jul 2012 @ 6:27:35 am from IP # -
ralfroedger
MemberAny comments / exposure with DG fibroglass windows?? Sovereing Tasi?
Posted Sunday 5 Aug 2012 @ 9:50:07 am from IP # -
kmcgraw
MemberHello I am planning to replace existing windows with double glazed for both heat/cool as well as sound reduction as there is a concrete factory across the river. Is there a checklist of what to look for when shopping around? Miglass I think is very comprehensive but they don't do measure and quotes which is very disappointing :(. Most greatfull for any advice
KarenPosted Wednesday 15 Aug 2012 @ 1:11:27 am from IP # -
kmcgraw said:
Hello I am planning to replace existing windows with double glazed for both heat/cool as well as sound reduction as there is a concrete factory across the river. Is there a checklist of what to look for when shopping around? Miglass I think is very comprehensive but they don't do measure and quotes which is very disappointing :(. Most greatfull for any advice
KarenHi Karen,
you are right - as we are supply only we do not perform site measures as this aspect is typically left up to the installer. Most large fabricators will perform these site measures (and potentially installation) for you but please note this is not necessary for a rough quote. Providing rough overall measurements and styles will more than suffice, and you are then able to utilise these same dimensions for a quote from several other companies quite easily (without a measure each time).
I can guide you through this process if you would like.
If sound (acoustic reduction) is your main concern i would suggest the most cost effective solution would be to remedy your existing windows rather than a new window system.
Thanks,
KurtPosted Thursday 16 Aug 2012 @ 11:26:03 pm from IP # -
Etherealise
MemberApologies for reposting from my conservatory thread, but I'm wondering if double glazed low e 366 glass (http://www.cardinalcorp.com/products/coated-glass/loe3-366-glass/) would be advisable for a large north facing glassed area (conservatory with glass roof, all existing glazing must be replaced).
Ideally I would have preferred glass that allows more solar gain than this for winter, in keeping with passive solar principles, but there are problems with shading solutions (cost and they would block the views). I gather this low e 366 is a good solution to reduce overheating where shading isn't practical?
Posted Sunday 19 Aug 2012 @ 8:26:20 am from IP # -
TonyT
MemberFor standard glass U = 5.9W/sqm/degC
For low E glass U = 3.6W/sqm/degC
The data sheet for Low E366 at
http://www.cardinalcorp.com/products/coated-glass/loe3-366-glass/
avoids providing its U value.Posted Sunday 19 Aug 2012 @ 10:14:49 am from IP # -
Etherealise
MemberThanks TonyT. Interesting they don't include the U value. Also no SHCG though I have an idea already that it is low.
Posted Sunday 19 Aug 2012 @ 12:56:38 pm from IP #
