Retrofitting Double Glazing


#1

We have large windows and are losing a lot of heat through the glass, so we are considering retrofitting double glazing. We have a company called Ecostar coming tomorrow to measure up, discuss the options (UPVC vs aluminium, etc) and give us quotes. Their product is manufactured in England and looks to be high quality.

The other company I’ve looked at is Sustainable Construction Services, which has a German-manufactured product which also looks to be high quality.

Does anyone here know anything much about double glazing? The particular things I’m interested in are –

  • Does anyone know about the reliability and quality of these two companies, Ecostar and Sustainable? Alternatively, can anyone recommend a company?

  • Does anyone have experience of what sort of difference it actually makes when you retrofit double glazing? Can you really feel a substantial difference? (I imagine the answer to this question is yes, if you fit good quality units and they are properly installed.)

  • From what I’ve read, double glazing is also good in summer at keeping heat out, although it seems better at keeping you warm in winter than at keeping you cool in summer. Does it actually have a noticeable cooling effect in summer?

Any other comments would be appreciated. It’s very expensive, and I would certainly not want to spend the money involved without being sure that I was dealing with a reliable company and the benefits are tangible.


#2

I looked at it a few years back and found it was too expensive given the potential benefit.

What I learned going through that process was:

  1. the frame needed to be insulated, especially if it was metal, as heat was just escape that way.

  2. there were too many other weaknesses in the insulation of my house to make the investment actually worthwhile. I would have needed to upgrade the insulation in my walls and roof and properly seal all my doors, otherwise the heat would just continue to escape there (which was a greater problem for me than the windows once I looked into it.

Hope that helps. Good luck.


#3

I’m of the same opinion as AD Don. If I was to get double (or even triple!) glazed windows installed it would be just one step of many to improve the insulation of the house.


#4

Thanks to both of you. The insulation of ourhouse generally is pretty good; it’s only 12 years old (not built by us) and the walls and roof are fully insulated. But I’ll investigate further.


#5

I’d recommend speaking to a services engineer who specialises in ESD.
Double glazing is a large expense and depending on the R value (or U value) of your wall insulation, roof insulation and what heating and cooling system you are using, you might find that a good performance single glazed unit (Viridian Has many Aussie made glass types depending on requirements.
You’ll also find that what direction the glass is facing might mean that no performance glass is required.
I’ve also found in some instances that the kind of glazing chosen works differently in summer than at winter so the wrong choice could throw out the balance and actually be more costly as far as running costs throughout a full year.

I wouldn’t switch to double glazing unless you need it for acoustic purposes.


#6
I'd recommend speaking to a services engineer who specialises in ESD. Double glazing is a large expense and depending on the R value (or U value) of your wall insulation, roof insulation and what heating and cooling system you are using, you might find that a good performance single glazed unit (Viridian Has many Aussie made glass types depending on requirements. You'll also find that what direction the glass is facing might mean that no performance glass is required. I've also found in some instances that the kind of glazing chosen works differently in summer than at winter so the wrong choice could throw out the balance and actually be more costly as far as running costs throughout a full year.

I wouldn’t switch to double glazing unless you need it for acoustic purposes.

ESD is Environmentally Sustainable Design?


#7

I’ve been considering DG of our bedroom windows for the acoustic benefits alone due to neighbor’s dogs and traffic noise. Does it make a significant difference in a brick veneer dwelling?


#8
I've been considering DG of our bedroom windows for the acoustic benefits alone due to neighbor's dogs and traffic noise. Does it make a significant difference in a brick veneer dwelling?

Yes, for high frequency noise inparticular. Fow lower tones, not as much, but as glass is extremely hard, it’s a better low freq blocker than most.

If you want it to stop lower frequ’s go at least 6 mm glass at least. The thicker the better.


#9

Posted in wrong thread…

I’m not to sure what the question is. Are you talking about fitting new d/glazed windows into the house, removing old windows … or are you wanting to replace the panes with new d/clazed replacements?

The 2nd can be a viable option, especially if the window frames are timber.

We experimented a few years back with d/glazing over the top of existing glass, which is complex but can be achieved. There is a simple way, but you need to be willing to remove the extra glass panel & clean in between on a semi regular basis.

As noted, any insulating efforts are only as strong as the weakest link. A completely R3.5 inso’d room will lose 50% of it’s efficacy, with just 1 squ metre of it missing for example. Sometimes, blinds + heavy blockout drapes + well fitted pelmets will acheive a btter result on windows than d/glazing, but of course all of that PLUS d/glazing is better than that alone on single glazed, but perhaps only 20 - 30 % for that squ metreage.


#10

I think I’m talking about removing existing windows and frames and replacing with DG units. I’m definitely not talking about placing a second pane of glass over the existing frames. I’ve contacted an ESD consultant to see about getting independent advice.


#11
I think I'm talking about removing existing windows and frames and replacing with DG units. I'm definitely not talking about placing a second pane of glass over the existing frames. I've contacted an ESD consultant to see about getting independent advice.

Good job buddy.

It’s rare that people would want to go to the expense of doing what you’re doing. Especially when there is no Australian Code that forces you to do so in a residential home. But it is worth it if you’re finding that your house cannot keep a stable climate through the year.

There is another cheaper option to consider. I cannot recall the company, but I got onto one earlier this year that can place a film on clear float glass and it’ll help you with the U-value / R-values that you need. These used to be utter crap ten years ago (it would bubble, it would perform well on installation but longevity was limited, etc.) but apparently the technology has gotten so much better over the last few years.

Do you have an old home? If each room has those old school vents, you might want to try and block them up. Some people have told me that they did it a long time ago and ended up with mouldy ceilings, but I’m yet to see one react that way. Any house built in the last fifty years doesn’t have room vents.


#12

We removed existing windows and had double glazing installed. We have PVC frames as it had a good R value and cheaper than timber.

Blummers32 is right about insulating elsewhere to make it viable. …we have underfloor, wall, roof and door.

Canberra winters have been so much better as a result. We rarely need the heater on.


#13
I've been considering DG of our bedroom windows for the acoustic benefits alone due to neighbor's dogs and traffic noise. Does it make a significant difference in a brick veneer dwelling?

Yes, for high frequency noise inparticular. Fow lower tones, not as much, but as glass is extremely hard, it’s a better low freq blocker than most.

If you want it to stop lower frequ’s go at least 6 mm glass at least. The thicker the better.

No like button, so cheers mate.


#14
I think I'm talking about removing existing windows and frames and replacing with DG units. I'm definitely not talking about placing a second pane of glass over the existing frames. I've contacted an ESD consultant to see about getting independent advice.

Good job buddy.

It’s rare that people would want to go to the expense of doing what you’re doing. Especially when there is no Australian Code that forces you to do so in a residential home. But it is worth it if you’re finding that your house cannot keep a stable climate through the year.

There is another cheaper option to consider. I cannot recall the company, but I got onto one earlier this year that can place a film on clear float glass and it’ll help you with the U-value / R-values that you need. These used to be utter crap ten years ago (it would bubble, it would perform well on installation but longevity was limited, etc.) but apparently the technology has gotten so much better over the last few years.

Do you have an old home? If each room has those old school vents, you might want to try and block them up. Some people have told me that they did it a long time ago and ended up with mouldy ceilings, but I’m yet to see one react that way. Any house built in the last fifty years doesn’t have room vents.

No, the house was built in 2001 and we bought it 3 years ago. It’s brick veneer and a good quality build, so I’m pretty confident that the insulation generally is good. It’s a bit surprising that they didn’t build in double glazing considering the standard of the house generally, but then it was much less common 15 years ago. It’s still not common now. I’m just very keen on it because I know how much difference it makes when retrofitted to houses/apartments in Europe.


#15

Building standards have improved heaps for insulation in the last 5-10 years, haven’t they??


#16

I thought insulation has been required for a very long time. Anyway, I’ll find out how ours is when the ESD consultants get to work. If they reply to my inquiry, which they haven’t done yet.


#17

From watching Grand Designs, EVERYBODY double glazes in the UK. Understandable too, considering the low temps they have. I am amazed how uncommon it is in Australia, given the high temperatures we have. I think one of the main reasons is its comparatively expensive in Oz.


#18
From watching Grand Designs, EVERYBODY double glazes in the UK. Understandable too, considering the low temps they have. I am amazed how uncommon it is in Australia, given the high temperatures we have. I think one of the main reasons is its comparatively expensive in Oz.

I think it’s a lot better at keeping heat in than out. It does cut temperatures to some extent in summer, but not a huge amount. I want it for winter, not summer.


#19

Not sure, last time I looked at any of this someone was telling me it’s really not worthwhile to do too much to new new builds (from some point in the 2010s…) as they’ve bumped up the minimum standards substantially. Your joint (2001) would be from before that.

Haven’t done all that much digging though.
We’ve got an open plan timber house, on stumps, with very very high ceilings, lots of big north-east & north-west facing windows = heat ■■■■■■ into & out of every orifice. We’d virtually need to pull the whole joint apart & start again.

Sounds like blummers is better qualified to fill in the gaps


#20
I thought insulation has been required for a very long time. Anyway, I'll find out how ours is when the ESD consultants get to work. If they reply to my inquiry, which they haven't done yet.

You should have a set of the building plans somewhere, no? I can’t remember if they come as part of conveyancing checks, or along with the title on sale these days, but if not, a visit to your local council should reap you a copy, hopefully at minimal or no cost. That will tell you what the R ratings are for your inso in the ceiling & walls, in fact they could just tell you, but it’s always good to have a set of the plans, & or the building permit.

If it was built by a mass builder it’s doubtful they’ve gone any further than minimum required, but if it’s been a custom build or from a high end speculator, it’s possible they’ve gone beyond that.

The higher the ratings, the more single glazing is letting the team down. If you have 1.5 walls & 2.5 or less ceilings as was standard 2001, it will make less of a difference.

Beware of consultants from window companies & do plenty of web research. It’s not that big a deal now, as d/glazed has been mandatory since they adopted 5 star rating for all new builds in Vic, & is not worth the premiums they like to charge most of the time. I had one client who paid a fortune with a big fancy sell from a consultant, only to have me replace a 15k house lot 2 years later because there was condensation forming on the internal frames in winter. Company was going to replace for free … went bankrupt 3 months after they were informed.

It’s an eco unfriendly jungle out there,… lots of snakes in it.