I asked a similar question a while back. Some big differences - depending on whether you keep your joinery and change the glass, or new joinery. In either case is the joinery wood or aluminium. If wood how straight and square and deep is it.

Haven't done anything yet and waiting to see how our first winter goes. Our best quote was over $25k for one room - it has a lot of glass.

Have not heard anything good about lower cost systems that leave your glass there and add a 2nd layer to it.

Are you talking about timber or aluminum windows. And if they are aluminum , are they old as they maybe near end of life? You can get timber windows retrofitted with proper double glazing, but I understand it can be expensive, probably due to the labour.

We had all our Windows replaced by Thermalframe, who do PVC double glazing, around a decade ago. They're still working well and looking good, even the one that was done earlier by a few years. We have two PVC external doors and one aluminum, done by different vendors.

Based on what others have told me, be prepared for a significant wait for a quote, then another significant wait for fitting. It could take six months, even a year to get them fitted. They're just super, super busy.

Don't go aluminum if you can help it. We have an aluminum front door, thermally broken, it's inferior in every way. It doesn't seal properly despite them having come back half a dozen times to try to get it to seal. It's single seal. The stainless steel fittings are going green only a few years after being fitted, they need to be regularly cleaned. It's much more difficult to open, partly because we got a stupid little 2 inch release instead of a proper handle. My tip is to get a proper sized handle, not a little release and a big pull bar, as you need the leverage to pull the door latches properly closed and seal. The aluminium place we got it from in Upper Hutt (I'd rather not name them) only told us after it was fitted that this is a problem with retrofit and that proper sized handles are the best idea in retrofit and most cases. The services of the place we got it from was good but it doesn't make up for a product I think is fairly poor. It looks good though, colored whereas PVC comes in white or wood grain.

Unless you are really in love with your old window joinery then you should investigate full replacement.

I got a quote for retrofit double glazed in the existing frames and it came to ~$25k (lots of labour involved).

I then contacted a firm that did inserts in the existing opening reusing some of the old joinery, they flat out said, don't bother go full replacement.

A quote for full replacement including installation came to ~$16K!! 

Going new also means you don't have all the drafty ill fitting frames. 

I did PVC inserts. Basically the only keep the outer frame, all the interior framing like around the windows is replaced with PVC. It worked very well.

johno1234: Who did the work @shanes and are you happy with the result?

I didn't go ahead with any of the options at the time as other stuff came up.

There was a 9 month lead time as they supplied all the new builds as well, so I am assuming the quality would have been good.

Not sure what area you are in, but I was talking to Fisher Windows in Masterton.

timmmay:

 

 

 

Don't go aluminum if you can help it. We have an aluminum front door, thermally broken, it's inferior in every way. It doesn't seal properly despite them having come back half a dozen times to try to get it to seal. It's single seal.

 

That doesn't sound right, although there are different manufacturers and profile designs, so they are not all the same. I have aluminum TB frames and they don't let any noticeable air flow through and that is even with very high wind blowing against it. 

mattwnz:

 

That doesn't sound right, although there are different manufacturers and profile designs, so they are not all the same. I have aluminum TB frames and they don't let any noticeable air flow through and that is even with very high wind blowing against it. 

 

True. I'm sure many are fine. I have a very small sample size of one aluminum door and two PVC doors. The PVC are hugely better designed, properly sealing, double seals, adjustable hinges. The expensive aluminum door doesn't have any of that.

Thanks for all you replies.

Sorry in advance if i use some wrong terminology. My house was build in the 1960s, with aluminium frame windowns. Not sure if they are thermally broken, how can I check?

I currently got a quote for 30K to replace all the windows with double glazing (There are a lot of large panel windows in the house). How they explained it to me was they will take out the single plane glass and put in a new double glaze and replacing all the old seals and removing the angled outer sash to accommodate the new double glaze. 

Currently, I don't really notice any wind coming into the house on windy days through possible gaps in the windows

panda123:

Thanks for all you replies.

Sorry in advance if i use some wrong terminology. My house was build in the 1960s, with aluminium frame windowns. Not sure if they are thermally broken, how can I check?

I currently got a quote for 30K to replace all the windows with double glazing (There are a lot of large panel windows in the house). How they explained it to me was they will take out the single plane glass and put in a new double glaze and replacing all the old seals and removing the angled outer sash to accommodate the new double glaze. 

 

Currently, I don't really notice any wind coming into the house on windy days through possible gaps in the windows

shanes:

johno1234: Who did the work @shanes and are you happy with the result?

I didn't go ahead with any of the options at the time as other stuff came up.

There was a 9 month lead time as they supplied all the new builds as well, so I am assuming the quality would have been good.

Not sure what area you are in, but I was talking to Fisher Windows in Masterton.

Nobody else has mentioned Homerit so far.  One of my colleagues retrofitted their PVC joinery and raved about it.  I had a look and decided to follow suit around 5 years ago, looking at several of their designs.  Awesome result, removing the old wooden windows and front door with full replacements.  The PVC frames are thicker than the old wooden frames, but I could not fault the quality.  Initially I only did half the house, but the different was so noticeable we did the rest a short time later.

While Auckland-based, this company may have installers nationwide.

panda123:

 

Thanks for all you replies.

Sorry in advance if i use some wrong terminology. My house was build in the 1960s, with aluminium frame windowns. Not sure if they are thermally broken, how can I check?

 

I currently got a quote for 30K to replace all the windows with double glazing (There are a lot of large panel windows in the house). How they explained it to me was they will take out the single plane glass and put in a new double glaze and replacing all the old seals and removing the angled outer sash to accommodate the new double glaze. 

 

 

 

Currently, I don't really notice any wind coming into the house on windy days through possible gaps in the windows

 

common way to check for thermally broken is look for condensation on the window frame. 

all single glazed windows will not have thermally broken frames. with a 1960's house they will not be the original windows. odds are windows where getting rotten and people where talked to into getting crappy aluminum windows instead of fixing the good wooden ones. its possible you could even have the terrible 70's aluminum windows in which case just replace the whole window. no point fitting good glass to rubbish windows.