Morning all. I am trying to figure out which windows are good and which lost their seal. I have four large sliding doors looking East every morning some of them have dew on the outside and some don't. The humidity is high here in the mornings, the ground is covered with the dew along with anything out side. So I am guessing the windows with the dew are good and the dry ones are not? I will be replacing the windows one at a time over the next year, and want to start with the bad ones. The inside of the house temp is set at 70 and the dew point has been around 71.
I did Home Inspections for over thirty years. This is something I looked for every day.
Insulated Glass (IG) windows tend to fog in cold weather and un-fog in warm weather. Check them on cool or cold mornings and on the shady side of the house.
You can also press an Ice Cube onto the glass for a few minutes and see if the interior side of the glass fogs or gets condensation on it. You will meed to wipe off the water on the spot where the ice was to be sure the condensation is on the inside.
(Home Inspectors found so many fogged windows local Realtors tried to define failed seals as "not a Problem" so the sellers they represented would not have to pay for repairing them.)
what the pay back is for replacing? Long I suspect. The biggest bang for the buck is double pane and low e glass. It could well be that you will never get a pay back from replacement of just the vacuum.
Moisture forming on the outside of the sealed glass panel in the house or outside is not a sign of seal failure. Moisture between the two panes is a sign of seal failure. I went through this discussion with some of my windows which did in fact have moisture between the panes. They shipped me new sealed panels under warranty.
Your inside temp is below the dew point, so the fogged ones have the least insulating value. Set a glass of ice water out with a glass of warm water beside it, and see which fogs. Another test, would be to tape a thermometer to the outside one of each type.
However you might be able to prevent the fogging with some kind of glass x or fog-x if it is just a matter of aesthetics.
Bill I think you are correct. There is little or no payback replacing like I G panes with Like panes that are sealed.
There is never a vacuum between the panes. The quality panes have Argon between them. It is a slightly better insulator because it resists forming rolling currents that transfer the heat.
They tried and may still try to make them with something like Aerocell, (SP?). It's a clear foam that is even better at restricting currents. Not sure it is or was successful in the long run because it shrank and discolored.
If your old windows did not have a low-E coating that would be an improvement and would just about double the effectiveness of the windows at resisting heat transfer.
I think it would take more than the lifetime of the windows to recover the cost of replacement in fuel savings even if you added Low-E and sealed panes.
Beyond that, After a house is reasonably well insulated, the principle source of heat loss is air leakage. Many houses have more than one Air Change an Hour. And worn windows can be a large part of that. But, I persist in believing that if you replaced the windows with ones with Low-e, perfectly sealed panes, triple panes and superior weatherstripping, things like Cam Lock Euro-Style casements, you will never get your money back.
Aesthetics and pride of ownership are completely outside this assumption.
Incidentally, the old windows with storm windows were more energy efficient that IG windows. The Air space was just about optimum and there was two sets of weatherstripping.
on the outside of the window. There is no fogging or any other problems for windows installed in 1997. These are all big sliding doors one 6 foot than two 8 foot and one more 6 foot door all in a row. The gable has glasswork in it also, so it pretty much makes the entire east side of the house a wall of glass. I am going to have the top windows tinted to stop the heat from coming in most of the day. The sliding doors I am not sure yet if I will get just the glass replaced or the entire door unit. All depends on cost. They all still slide pretty well the screens are all intact and the frames look good.
Mike, are you sure the difference between the windows having moisture on the outside and the ones that don't isn't that one side or the other is covered by the screen while the other side isn't. If the moisture is not between the glass then the seals are not broken and no reason to replace them. George
The two 8 foot doors always have moisture and the two 6 foot doors never do. The screens are off the doors right now because I was cleaning them and the track along with replacing the wheels. I just haven't put them back on yet. If the seals are still good then I am not as worried about them.
You will know this winter if the seals are bad you will have fog in between the panes of glass.
After a few years the fog between the panes will leave a residue that will obscure your view. When looking thru the fogged glass bothers you then it is time to replace the glass.
I do not think tinting the windows will keep much heat out. The dark glass absorbs the energy gets hot and the heat all the heat is in the house. If the goal is to stop the sun light from fading your carpets and furniture then tint the windows. The best way to keep out the heat id a solar screen on the exterior, the screen absorbs some of the energy before it enters the house.
Note most window manufactures do not recommend aftermarket tinting and will void any warranty if installed. the argument is the added heat damages the seals.
As usual Walta is correct. Most manufacturers void any warranty if you install aftermarket tinting. However, if your units were installed in 1997 it's unlikely you have any warranty you could enforce left.
The reason is the tinting causes the outer pane to warm much faster than the inner pane and expand, in effect squirming, and it breaks the seal.
It's amazing yours are still intact after 23 years.
The main benefit is in double pane, then some more gain from low E, vacuum is last, just gives you a hair more insulation value in the 1/2" or whatever between the panes.
I tend to think it's a bit of a negative because if you lose the seal between the panes the lack of atmospheric pressure between them draws air and moisture in and you get the foggy window problem.
From what the OP describes, it doesn't sound like there is a problem - unless that dew is in between the panes (haven't read all the posts yet, just the first couple). I would go with your suggestion of the thermometer, but if there's no fogging between the panes I wouldn't even be worried about this.
That is generally the best solution for this problem. Out here we usually put a shade ramada over problem exposures, one better than tinting but a bit more expensive to do.
Although tinting does heat up the outside pane of glass (assuming it is applied to the outside that is), it also blocks some sunlight and the resulting radiant gain inside. Putting tinting on the inside is worse than on the outside.
A shading structure is much better, the structure itself is what warms up, far from the windows and interior of the house.
I've almost finished the one we started early this summer. Just need a bit more railing and a hand rail for the stairs:
This faces almost due west. At the height of the summer the setting sun is a little north of west, we were careful to orient the shade slats so that they would provide maximum shade during the summer as the sun sets. Cloudy this afternoon, so you can't see the effect.
