How do I stop condensation on windows?

Stop condensation by reducing indoor humidity and keeping warm air moving across the glass.

If it’s inside the window:

• Keep humidity around 30%–50%; use a dehumidifier if needed.
• Run bathroom/kitchen fans during use and for 20 minutes after.
• Open trickle vents if you have them.
• Use a ceiling fan on low to circulate air.
• Keep curtains slightly open so heat can reach the glass.
• Add window insulation film in winter to create a warmer air gap.

If moisture is between the panes:

• The window seal has likely failed.
• The usual fix is replacing the sealed glass unit or window.

If it’s on the outside:

• That’s normal on efficient windows in certain weather.
• It usually clears on its own as the glass warms up.