For the sake of discussion we have a 2400 square foot house that is listed at $265,000 here in Dallas Texas. Most homes built from the 80's forward have had builders grade aluminum double paned windows. They often came with a 5 to 10 year seal failure warranty but they seldom have anything more than this. The end of our warranty hopes just came upon us.
This home would have on average 18 to 24 windows and probably about 8 to 10 panes of glass that might be showing condensation between the panes or white calcium build up between the panes.
The home inspector will not be able to see all the windows with seal failure as many times the actual tell tale signs are years away for some of the windows. Back to the example home. Twenty four windows will have 40 or so lites of glass and if 8 get flagged (tagged, dotted, whatever the inspector did to them) that's probably a win as there are 8 more just about to go out.
Cost to replace fogged windows. On average the small ones are $125.00 and the big ones above them are $175.00. Big circle tops and arch-top shaped glass replacement is considerably more and can be $600 to $1000 depending on the size. This means the big beautiful one in the foyer.
As this problem is usually noted at the time of sale, here's another option. If 8 flagged units can be settled with the new buyer at $800 to $1000. That's always a win for the seller. No scheduling, no issues.
For the buyer that can be a win too. A thousand towards a better solution than glass replacement might be a good thing. You can both haggle over the other $500 in labor and variables that could come into play.
Glass replacement will fix the clarity of the glass but not the energy efficiency of the window. Most 80's to 90's era homes have that builders grade frame and installation that just won't seal well after a period of time. New glass in a builders grade window is much like new tires on your 1972 Pinto. You'll be stuck to the road better, but you're still driving a 1972 Pinto.
A long term solution is a good vinyl replacement window with a lifetime warranty that can offer better U Value and Solar Heat Gain Coefficient. The builders grade clear insulated window allows 87% of the heat through the glass whereas a quality replacement window will only allow about 21% of the heat to pass through it. That's furnace heat staying in and sunlight heat staying out, all year long!
Now I admit that I am partial to replacement windows as I've had a lifelong career in Dallas and surrounding areas as a window guy, but the reality of how happy folks are when their house is suddenly airtight is so very motivating to me. It makes me want the job to be perfect so the results are notable. Enough about me though this is about foggy windows isn't it?
So now you know the options. Google Glass Replacement if glass only is what the inspector came up with. I also recommend you enter the zip code and look for a glass shop closest to your home. That is the guy who can do it cheapest in most cases. If you're a house flipper replacement windows may be a better option to put a fresh face on the property. In your case you'd search for Replacement Windows or Vinyl Windows. If you're in Dallas and surrounding areas I hope you'll let us weigh in on your project as well. ~ Dave Traynor