Retrofit - replace glass only single pane to double pane in wooden frame.

Hello there,
It might have been discussed already… I spent little time on searching for it on the forum, so do not bash me, please.
My problem is as follows.
House was built in 1982. It appears windows are still original. Currently I have double hung, all wood, single pane with storm windows/screen. They are warm (frame, not glass!!), not leaking air, and look still good. Frame is still stiff, not bent anywhere or such.
Since it is MI (today outside is -15C – sorry, I am a metric guy) I get significant condensation on the glass inside (even with the storm windows in place). In order to minimize it I thought about new windows, but the lowest quote is roughly 4k. With windows matching our current exterior and interior it is another 50% more. Therefore, an idea of retrofitting double pane into current frame came to my mind.
Initially I made a “double pane” myself – I simply cut a sheet of glass and secured it from outside in the frame. Result – much warmer glass and condensation cut by about 80%.

I found double pane (made to order) Low-E. It costs roughly 65 USD per piece (a piece is 32”x24&#8221 and I have 12 of those pieces plus a pair of 32”x16” at 42 USD… so we are talking about 850 USD plus taxes and misc. Labor is an extra 22/piece if I want them to replace the glass.

So here we come to a question – shall I replace the glass only and keep the old frames or go for a whole window? Is it OK for the window frame? It will hold the extra weight (I got one “retrofit” done, and it works OK – will stay in place when open). But I wonder, as someone told me that the frames will go bad and the double pane will start leaking within a year or so (it was one of those “quote guys&#8221.

Some additional data.
Today in the morning I measured temperatures in the two rooms (the regular one and the test one with “new glass&#8221. I used infrared thermometer.
Outside is -15C, wind 15 km/h. Inside the rooms is about 19C. All temps are in C.
Wall: 17.1, frame 14.5, glass 3.8 (about half way condensation – that is 12”, similar upper sash)
Wall: 17.4, frame 14.5, glass 9.5 (some condensation – that is 3/4” on the lower sash, upper minimal, less than 1/4")
The product I would be getting is Synergy Series by VPI Quality Windows. U-factor 0.30, SHGC 0.22 (for their window – I am not sure about the glass itself).

Please advise.

EDIT:
the total thickness of the double pane is 3/8", if it matters.

My consideration would not be the glass as far as retrofitting or replacing the units.It would be that you're present windows are all wood.You say they are in good shape now but how long will they be before having to replace them and losing the cost of the replaced glass if you go that way.The new windows would be double pane low e and maintenance free.

mako1 said:

My consideration would not be the glass as far as retrofitting or replacing the units.It would be that you're present windows are all wood.You say they are in good shape now but how long will they be before having to replace them and losing the cost of the replaced glass if you go that way.The new windows would be double pane low e and maintenance free.

Click to expand...

Thanks for your input.
Sure, I have no doubts they would be great, yet I would have to spend 6 times the money, which I do not have.
Besides, I do not feel like I want to replace them as they are not really broken.

How long they will live? I do not know.
That's why I asked the question here. I do not have great experience with them.
I can advise you on your car, or PC, but not really aging of wooden windows.

I lived in a house where 60+ years old windows were still fine, but that was a different country, different type of widows, although same climate.

Welcome to the site.
My experience with window replacement companies is not good.
To change a window properly you want to completly remove everything down to the rough framing, repair rot as there is alway some and install the new windows to the newest code requirments.
To often window replacers, remove the sash in install new windows into your old frame and don't come close to a good installation. That is why you here stories of more problems a few years later.
If money is tight and doing properly would probably be more than the quoted price and the windows are in reasonable shape now, I would go with just the glass replacement and expect that to be good for up to 15 years.
Keep in mind that one glass is 1.8"R" and two are double that.