Will a blind make condensation worse?
It can, but it does not have to. Condensation forms when warm, damp indoor air meets cold glass. A blind sits between that air and the window, so it can reduce airflow over the glass and leave the surface cooler and damper than it would be otherwise. A blind is rarely the cause. It can make an existing moisture problem easier to see or slightly worse, particularly if it is kept closed all day.
Why roof windows suffer
Warm air rises, so a loft room collects moisture from breathing, showers, drying clothes and cooking elsewhere in the house. The roof glass is often the coldest surface in the room, particularly overnight, so water droplets appear there first. The same thing happens on bedroom windows, but it is more noticeable above your head and can drip onto sills and paint.
What a blind changes
- Airflow. A tight blind traps a pocket of air against cold glass. If that pocket is damp, it can mist.
- Temperature. The blind keeps room warmth away from the glass, so the glass stays colder.
- Moisture on fabric. Water can collect on the lowest edge or on a headrail. Some materials cope with this better than others.
None of this means you need to avoid blinds. It just helps to choose carefully and use the blind sensibly.
Fabric choice
Look for a fabric that can be wiped and that the maker describes as suitable for damper rooms. Plain, smooth materials tend to be easier to wipe than heavily textured ones. A thick, absorbent fabric can hold water and may stain or develop marks if it is repeatedly damp. Fabrics are only described as mould-proof or antibacterial when the maker states it, and even then it is worth checking what that means in practice. See our overview of roof blinds.
Gaps help
A little space between the blind and the glass lets air move and carry moisture away. Very tight designs help with light and heat, but they can hold more damp against the window. If condensation is a regular problem, talk the trade-off through with us at the measure, and consider a blind that can be raised easily in the morning.
Habits that help most
- Open the blind in the morning. Let the glass warm and the moisture clear.
- Ventilate. Open the roof window slightly if you can, or use a trickle vent or extractor.
- Cut the moisture at source. Use extractor fans, put lids on pans and dry washing elsewhere where practical.
- Wipe the glass. A quick wipe of the lower edge prevents drips running onto the blind.
- Check the room temperature. A room that is never warmed will attract more condensation.
When the cause lies beyond the blind
If water is running down the glass every day, the cause is usually too much moisture in the air, too little ventilation or cold bridging in the window frame. A blind is not the cure for these. A heating engineer, window specialist or builder would be the right person to ask. It is worth acting on, because long-term damp can mark plaster and frames.
Frame and fit considerations
Blinds made to match a roof window frame sit neatly and usually allow the window to be opened. Ask whether the system you are considering allows ventilation while the blind is down. Our page on Velux roof window blinds explains how blinds are matched to the window.
Motors and pole control
People tend to leave hard-to-reach blinds shut, which is when condensation worsens. A pole, remote or motor makes it easy to open the blind first thing. See motorised blinds.
Next step
Tell us how often the window mists up and when. Every home is different, so we cannot promise to solve condensation, but we can help you choose a fabric and a style that copes well and is easy to open and wipe.
Book a free measure
If you would like a second pair of eyes on the window, book a free measure and we'll talk it through with you at home, with the actual glass in front of us. Or call us on 01642 424250.
