Windows, humidity and A/C?

[GC7]

South Florida in the summer is like this everywhere. The resort I stayed at had staff who spent their days squeegeeing the condensation off the outside of windows.

 

[CHenry]

dehumidifier won't do anything for moisture on the outside

Any moisture inside or out means the glass pack seals are gone and so is the argon gas.

 

[SoonerP226]

Usually when double pane windows do that, it's due to one of the seals going bad.

Double-paned windows are sealed to maximize insulation. If that seal breaks, cracks, or otherwise fails, they loose their insulation value. In some cases moisture can enter between the panes.

When my dad was looking at replacing the windows in his house about 30 years ago, he called a friend of his who did HVAC engineering. He told my dad that the R value of glass is effectively zero, and doubling zero is still zero. The insulation comes from what's between the panes of glass, so if it's leaking out, the windows are losing their insulating capability.

I'd guess that you wouldn't see the condensation in normal years, but this year has been so abnormally, obnoxiously, damnably humid...

 

[CHenry]

Renewal By Anderaon runs some great specials occasionally.
I did mine last may 2022 and saved several thousand dollars. Saw a huge difference in both winter and summer.

 

[SoonerP226]

Will get quotes from Pella, Anderson and Thermal Windows Inc out of Tulsa when it's time.

I'd suggest looking at Window World, too. My dad put them in the farmhouse not long after my folks bought it, and they still look and work great after more than a decade. My brother liked them so much that he's putting them in the barndominuim he's building.

 

[Catt57]

When my dad was looking at replacing the windows in his house about 30 years ago, he called a friend of his who did HVAC engineering. He told my dad that the R value of glass is effectively zero, and doubling zero is still zero. The insulation comes from what's between the panes of glass, so if it's leaking out, the windows are losing their insulating capability.

I'd guess that you wouldn't see the condensation in normal years, but this year has been so abnormally, obnoxiously, damnably humid...

To be fair, glass might be worse than 0 R value. It very efficiently conducts temperature. And you are correct. It's the gas between the panes that gives it insulation.

 

[-Pjackso]

...the R value of glass is effectively zero, and doubling zero is still zero. The insulation comes from what's between the panes of glass...

This is correct.
For the window overall U-value - the glass does provide a (very tiny) R-value via conduction, but it's effectively 0 (as stated).

Most of the insulating value of the window comes from the 'gaps' between panes. Heat transfer through the gap requires an 'air-loop' circulation (convection) of the internal gasses. This slows down the heat-transfer, which increases the R-value of the window. More 'gaps' (panes) = slower heat-transfer = improved R-value.

'Air' inside the window gaps works fine for insulating purposes - providing the air is DRY.

k-values of air: 0.0262 Watts/meter-K.
k-values of argon: 0.016 Watts/meter-K.
Per the values above, argon transfers about 1/2 less 'watts' of heat-transfer per area - but air is a viable gas to use also.

Overall heat transfer of windows with different 'gasses (air/argon)' and different 'gap' sizes:
https://www.engineersedge.com/heat_transfer/heat_transfer_coefficients_13822.htm
Material/Gas coefficients of heat transfer:
https://www.engineeringtoolbox.com/thermal-conductivity-d_429.html

 

[saddlebum]

I'd argue a dehumidifier allows your ac unit to not run nearly as hard to achieve the same perceived temperature, therefore setting the thermostat at 72 or 73 with drier air inside may yield the same "felt" results with less condensation on the exterior windows due to less temperature gradient. How do I know? We had the same problem two years ago...

it's just like a glass of ice water , cold inside warm moist air out side = condensation on the outside. he already stated he is not going to raise temp. the problem is usually by now it is hot and dry outside,but this year it is still humid and raining this far into august