Your home's windows don't need to be cracked or outright shattered for them to need repair or replacing; windows can suffer damage that isn't so visible, but which compromises the integrity and insulating properties of the glass. There may also be damage around the window frame, where it's not as visible and noticeable. Note a few signs that your home may need window repair or replacement, so you can know to call a repairperson or shop for new windows altogether.
Durable, strong windows should withstand the noise from nearby traffic, a school, dogs barking, and the like. If you should suddenly notice more noise making its way into your home than ever before, this can mean there are leaks around the window frame, and these gaps are now allowing in all that sound. The glass could also be etched and otherwise damaged so that it's not as thick and durable, or it may have come loose and away from the frame so that it now vibrates and allows those sound waves to pass through, rather than bouncing them off the glass. New windows can help protect your home from all that sound and make it quieter and more comfortable inside.
Condensation and fog
If condensation forms on the inside of window glass, cool air and moisture from outside are reaching the inside of your home; this can mean that the seals of the window have formed a leak. Have those seals checked for needed repair or consider replacing the windows to something with better insulating properties.
Dirt won't come clean
If you've tried cleaning the windows and dirt, streaks, and other marks don't seem to come clean, it may be that the windows are actually etched. Small scratches and scrapes can form along the glass, and dirt can then settle into these areas, where your squeegee just can't reach. This etching can compromise the integrity of the glass and make the windows look dingy and dark; have the glass replaced with something stronger so you avoid this problem in the future.
If you walk by a window and notice it seems a few degrees colder in that area than the rest of the space, this often means there are leaks around the windows or the glass is too thin to properly insulate your home. Have the windows resealed or replace them so you don't lose heating and cooling during the extreme seasons.
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