In short, your double glazed windows should not get condensation in your bedroom, or anywhere else in your home. However, it’s important to know what’s normal and what isn’t when it comes to condensation. You may assume that if your windows aren’t clear all the time, then there’s something wrong with them. This can sometimes be the case, but only when talking about condensation between the two panes of glass.
To make sure you don’t continue with failed double glazed windows or worry unnecessarily about a ‘problem’ that is actually perfectly harmless, we’ve put together our comprehensive guide to condensation.
Your bedroom windows have condensation on the outside
Condensation on the outside of your bedroom windows occurs when the air outside is warmer than the temperature of your double glazing. Outside condensation means your windows are not allowing any heat transfer, so, if you have some condensation on the outside of your bedroom window – relax! It just means your double glazing is doing a great job of insulating your home.
If you are bothered by how condensation looks on the outside of your double glazing, you could simply wipe it away if your windows are within reach. However, the best option is to simply wait, as the condensation will usually disappear when the sun shines directly on your windows.
Your bedroom windows have condensation on the inside
If condensation forms on the inside of your bedroom windows, it is usually the result of steam that may have formed from the shower, or bath, in your bedroom en-suite, if you have one. This will usually happen if you leave the en-suite door open so the steam travels into your bedroom. This is a natural phenomenon where water vapour turns back into liquid when it comes into contact with something cooler in temperature, like your bedroom windows.
However, condensation on the inside of your double glazing can sometimes indicate above-average humidity levels in your home and you may have a ventilation problem. If water vapour has nowhere to go, it will condense your windows, as well as your furniture, in carpets, and on walls. Excess moisture around the house can be very damaging to your home and to your family’s health. Encouraging air flow and letting fresh air in will naturally improve ventilation and lessen the chance of condensation on the inside of your windows.
Why bedroom windows suffer the most from condensation
There are a few key reasons as to why bedrooms are typically the worst-affected room in the house. Did you know that we exhale around 40g of moisture per hour when sleeping? As well as this, bedrooms are often unheated, so glass drops below the dew point, with curtains and blinds also trapping a layer of cold air against the glass. Finally, many people sleep with the door closed, which traps all of this moisture in the room.
How much moisture is actually being produced in your bedroom?
| Activity | Approximate moisture released |
| Two people sleeping (8 hours) | 1.5 litres |
| Showering (per person, per shower) | 0.2 litres |
| Bathing (per person) | 0.1 litres |
| Cooking and boiling kettles (per day) | 2-3 litres |
| Washing dishes (per day) | 0.4 litres |
| Drying clothes indoors on a rack or radiator | 5–9 litres per load |
| Using an unvented tumble dryer | 2-3 litres per load |
| Houseplants (per plant, per day) | 0.02 litres |
| Pets (per dog or cat, per day) | 0.05 litres |
A typical family of 4 can release up to 10 to 15 litres of moisture into the air in a single day. Without adequate ventilation, the moisture has to go somewhere. The coldest surface in your bedroom (usually the window glass, especially in the evening) is where it ends up.
Quick and easy ways to ventilate your bedroom and the rest of your home
- Open doors and windows.
- Dry laundry outside. Avoid draping wet/damp clothes and towels over radiators.
- Open your bedroom window trickle vents if you have them.
- Put your windows on the night vent facility keeping your home secure whilst still allowing airflow. (Especially if windows are behind a thick curtain/blackout blind or above a radiator etc.)
- Keep internal doors open (when not showering/cooking).
- In winter, open your windows periodically (Only when the central heating is off!)
What’s a healthy bedroom humidity level, and what’s the best way to check?
The ideal range for your bedroom and for any room in your house is 40-60% relative humidity. When you reach above 60% relative humidity, you will get condensation on cold surfaces. Above 70% is where you reach the risk of mould. A hygrometer only costs around £5 to £15, which will then allow you to check your humidity levels and follow the steps to solve these issues.
The dangers of ignoring bedroom condensation
Black mould (Stachybotrys) is the biggest risk from ignoring high condensation (higher than 70% relative humidity), as well as respiratory issues and aggravated asthma. Dust mites thrive above 50% relative humidity, and window frames can become damaged, as well as paint, plaster, and soft furnishings. Demonstrating the dangers of health complications from black mould, Awaab’s Law was introduced on 27th October 2025 due to the tragic death of 2-year-old Awaab Ishak, following a petition from his parents. This has changed legal landlord obligations on damp and mould for social housing. This was introduced as part of the Social Housing (Regulation) Act.
Bedroom-specific fixes for condensation
After you have fixed ventilation in your bedroom and home, there are other specific fixes for your bedroom to help combat condensation.
Step 1:
- Leave a gap behind the headboard and wardrobe (cold spots).
- Avoid drying clothes on bedroom radiators.
- Use moisture-absorbing crystals or a dehumidifier overnight.
- Run extractor fans in en-suits for 15 minutes after showering.
- Don’t overfill wardrobes against external walls.
Step 2:
- Use your hygrometer to check the relative humidity of your bedroom again. In the day and at night. If you have reduced the humidity to around 40% or lower, you are in a good spot. If you are still around the 60% or higher range, there may be issues that require a professional,
When do I need to call a professional?
Seal failure on the windows. Condensation between the panes indicates a seal failure, and the seals will need to be replaced. Other issues could be black mould returning despite your changes, condensation pooling and persistent damp patches on walls. If you are experiencing these issues, speak to a member of our expert double-glazing repair team. We can repair double glazing and triple glazing.
You have condensation between the double-glazed panes of your bedroom windows
The appearance of condensation between the panes of glass in your bedroom windows, or in any other windows in your home, indicates that the windows are not doing their job properly. The air-tight seal holding the insulating gas inside has failed, letting all the insulating gas out. When this occurs, water vapor can get between the two panes.
This means your double glazing can collect moisture, which can lead to further damage to the window, whilst wasting drastic amounts of energy as you attempt to heat your home and replace the heat being lost. Double glazed windows should not be collecting condensation between the panes, and if you have condensation between your panes, you definitely need new windows.
Get a quote for new windows from Seal-Lite
Consider triple glazed windows for your bedroom and the rest of the home
For extra protection against the elements, you could also consider triple glazing. Triple glazed units provide South West homeowners with unparalleled energy confinement and noise reducing qualities, that double and single glazing simply cannot compete with. In comparison to double glazing, triple glazed windows can provide an additional 15% energy saving each year.
Seal-lite are here to help with your new windows
Seal-Lite of Clevedon are a specialist installer of high-quality home improvement solutions. We’re ready to help with your next home improvement project, call us on 01275 342 656 or receive your free no-obligation quote here.