Why is water collecting behind my blinds every morning?

What is actually happening at the glass

Air holds moisture in proportion to its temperature. Cool it and it must release some, which it does on the coldest surface available, usually the glass or the frame. A blind pulled down creates a narrow, still air gap that stays colder than the room, so the air in there reaches its dew point earlier and drops its water onto the glass and sill.

This is why condensation is worst on north facing windows, in bedrooms overnight, and in kitchens and bathrooms where the moisture load in the air is already high.

• Worst overnight in bedrooms: breathing adds moisture, and the room cools.
• Worst in kitchens and bathrooms: cooking, showers and drying laundry.
• Worst on north elevations: the glass never gets a warming spell of sun.

Free changes worth making first

Open the trickle vents in the window frames if you have them and keep them open through winter. Leave a hand's width gap at the bottom of the blind overnight, or lift it a few inches, so the air behind it can circulate. Wipe the sill in the morning rather than leaving standing water to soak into the frame or the plaster.

In a bathroom, running the extractor for fifteen minutes after a shower with the door closed removes more moisture than airing the room for an hour afterwards. In a kitchen, a lid on a pan of pasta makes a genuine difference to how much water ends up on the window.

• Keep trickle vents open through the heating season.
• Leave the blind slightly raised or vented overnight.
• Extract at source in bathrooms and kitchens, with the door shut.
• Dry laundry outside or in a vented space, never against a cold window.

Which blinds cope with a wet window and which do not

Rigid materials handle repeated wetting far better than fabrics that wick. PVC and faux wood venetians, moisture resistant roller fabrics and aluminium slats all wipe clean and dry without marking. Natural fabrics and untreated real wood are the ones that stain, warp or grow spots.

The other factor is how the blind sits. A blind fitted tight to the glass traps a smaller, colder air pocket. Fitting slightly forward, or choosing a slat that allows air to pass when tilted, keeps that pocket moving.

• Good in damp rooms: PVC and faux wood venetians, moisture resistant rollers, aluminium slats.
• Poor in damp rooms: untreated real wood, natural weave fabrics, unlined Romans.
• Better fitted forward of the glass than tight against it.

When condensation is telling you about the window, not the blind

If you see misting between the panes of a sealed unit rather than on the room side, the seal has failed and no blind change will help. Similarly, water pooling inside the frame with no obvious airborne source can indicate a drainage or seal problem in the window itself.

We will say so rather than sell you a blind that cannot solve it. Replacing a blind to fix a failed sealed unit helps nobody, and we would rather you knew.

Getting the specification right for a damp room

For bathrooms, en suites, utility rooms and kitchen windows over a sink, we specify materials rated for the environment as standard, and we will tell you at the visit if the blind you had in mind is going to struggle. That conversation is free, and so is the measuring and the written quote.

We fit across East Kent from our Hythe High Street showroom, and coastal properties get particular attention: salt laden air alongside condensation is harder on fabrics and fixings than either would be alone.