Sash Windows - Double glaze, secondry glaze or leave alone??

[reubin78]

The front of our home has four bay windows. These in turn consist of (what should be!!) opening single-glazed sash windows and small 'fake' sash windows.

We are in the process of restoring these. Once the numerous layers of paint are removed, the timber appears general good and the mechanism sometime even works!!

My question relates to heat/sound insulation - should we consider Double glazing (glass only change), secondary glazing or leave alone (stick with the single glazed)?? I have read various articles but still do not have a clear idea of which direction to go. Hopefully, a few of you have faced this option and can talk from experience.

Double glazing (glass only change)
Expensive and sounds as though we'd never save enough to cover cost.
Windows need new larger weights to assist opening.
Existing window units have a 10-12mm rebate so not deep enough(?)

Secondary glazing
Cheaper but sounds as though they are prone to condensation (if not sealed - which original windows aren't)
Awkward as need to remove to open window

stick with the single glazed
Another cold Winter!! Are shutters a visually pleasing yet cost effective alternative?

Please note there is intentionally no option for replace with UPVC [/b]

 

[ronniecabers]

secondary glazing utilising Balanced vertical sliders and Pilk k ( heat retention glass ) would be the best bet in my opinion , still won't be cheap though. Or you could use a version of secondary glazing that using Magnetic tape and perspex, won't look overly pretty, but cheapere than sec glazing and replacing the sealed units

 

[Gazman16]

Without some pretty drastic routing out of the frames putting in double glazed units is a bad idea.
There needs to be a 5mm gap all around the unit plus ventilation and drainage holes and the spacers bars should be covered by the rebate and beads to protect the sealant from the elements.

Without the above measures you could end up having to replace units in as little as a year and no-one will guarantee them.

There are company's who specialize in making new sash's (double glazed) to fit into the existing frames but it wont be cheap.

There really are some authentic looking PVC sash windows about nowadays, Some have even been approved for use in listed buildings and conservation areas.

 

[reubin78]

Ours is not a listed property but it is located in the local conservation area.

Several of the non-road facing windows are UPVC and we are looking into replacing the most noticeable one with a sash equivalent.


Regarding, secondary sash. I have heard there are potential condensation problems. IS this correct and why?/how do we avoid?

 

[geraldthehamster]

Condensation issues will be a result of warm, moisture-laden air from inside getting past the secondary glazing and hitting the colder glass in the original windows. Properly sealed good quality secondary glazing should avoid this.

uPVC sash windows look OK from about 30 yards away...

Cheers
Richard

 

[reubin78]

Thanks for that. I had misunderstood - interpreting it has the condensation was forming on the secondry glazing! (Your logic makes far more sense)

 

[Gazman16]

Condensation issues will be a result of warm, moisture-laden air from inside getting past the secondary glazing and hitting the colder glass in the original windows. Properly sealed good quality secondary glazing should avoid this.

uPVC sash windows look OK from about 30 yards away...

Cheers
Richard

I totally admit that there are some horrible PVC ones around, Mainly the old ones. but the modern ones you can barely tell from a meter or so away (except for the fact they are clean and don't have paint splattered all over the glass).

Heres one I fitted recently. Its just a bog standard white one not the ones that are approved for conservation areas, Those ones have machined joins rather than welded and would most likely have a wood-grain effect on them.

Before

After

 

[geraldthehamster]

Fair enough, though the original looks in good condition, and nicer. That window is new though. I've seen some awful ones that have been in for a number of years, and gone blotchy and discoloured, as uPVC does. The mitre joints never look right either Nor do the fake glazing bars within the unit.

Sorry, no offence intended to your craft, but I'm not a fan of plastic replicas of original features.

Cheers
Richard

 

[Gazman16]

Fair enough I was just trying to bring a balanced view as I hate timber windows lol.

The windows were ok condition but right on a pavement and near a pub so they wanted soundproofing and better security as well as insulation.

It was the old PVC (and some really cheap modern PVC) that used to discolor, They have the chemical formulas and UV stabilizers all figured out now. Most of the big brand PVC suppliers give a 20 year guarantee against discoloration.

You can have full mechanical joints rather than welded miters it just costs more.

That customer chose the internal Georgian bar as it was cheaper and easier to clean but you can have Astragal bars instead http://www.imagewindows.com/atkinson.JPG
Its the same options you would have with new timber windows or sash's.