Condensation on Your Windows? Check This Before Replacing Them, by Practical Homeowner on YouTube. 13 min 23 s.
- Video length
- 13 min 23 s
- Time to do it
- 20 minutes
- Difficulty
- Easy
- Steps
- 10
What you need
Steps
Press a dry tissue against the glass. If the tissue comes away wet, the moisture is on the room side. If the glass stays cloudy and the tissue stays dry, look at the outside or between the panes.
Check the outside face from outdoors or through the glass. Thin dew on the exterior on cold mornings is normal and usually clears as the day warms.
Look for fog, white streaks, or droplets that sit inside the sealed gap and will not wipe off. That points to a failed seal in the insulated glass unit.
Measure indoor humidity with a hygrometer and note when fog appears. Cold glass, closed curtains, showers, cooking, laundry, and humidifiers all add moisture to the air.
Run the bathroom fan during and for 15 to 20 minutes after showers. Use the range hood while cooking, vent the dryer outdoors, and turn down any whole-house humidifier.
Let air reach the glass. Open curtains during the day, move furniture and plants away from the window, and run a ceiling fan on low to keep air moving.
Dry any water on sills and frames within 24 to 48 hours. Check paint, wood, drywall, and seals for soft spots, bubbling, or mold, and repair damage before it spreads.
If water appears during or after rain, treat it as a leak. Check the frame, seals, drainage slots, and flashing, or call a contractor rather than blaming indoor humidity.
Ask for a written diagnosis before approving replacement. Ask whether only the insulated glass unit or sash can be replaced, and why a full window is needed if it is.
Get the diagnosis to name the failed part, such as the seal, glass, frame, or flashing. Compare that explanation with a second quote before you sign.
Tips and common mistakes
Do not assume room-side condensation means the seal has failed; it often means the air is too moist or too still.
There is no single winter humidity setting that works in every home, so adjust based on what your windows show.
If fog is between the panes, ask about glass-only replacement before you price a whole new window.
Use a stable step stool and keep both feet on it when checking high windows.
Questions
Does fog between window panes always mean I need new windows?
No. The sealed glass unit or sash may be replaceable without changing the whole window. Ask for a diagnosis of the failed part first.
Why do my windows fog only in winter?
Cold outdoor temperatures make the glass cold, and normal indoor moisture condenses on that cold surface. Better ventilation and lower indoor humidity often help.
How do I know if it is a leak or condensation?
Water that shows up during or after rain, or runs down frames, points to a leak. Fog that follows showers, cooking, or cold mornings points to indoor moisture.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
