Condensation diagnosis
Tap through the questions below. You’ll land on the most likely cause and the
least disruptive fix to start with.
Start here
Where do you see condensation most often?
Windows (especially mornings)
Overnight / early morning
Short bursts, then off
Result: Read why windows get wet every morning.
Low heat most of the day
Result: Read why windows get wet every morning.
Only certain rooms
Result: Read why windows get wet every morning.
Rarely (trying to save money)
Result: Read why windows get wet every morning.
After showers or cooking
Result: Read why bathrooms get wet after a shower.
Mainly during cold weather
Result: Read why mould and condensation appear in corners and on ceilings.
All year round
Result: Read why the whole house can feel damp even without leaks.
Corners or ceiling edges
Mainly during cold weather
Result: Read why mould and condensation appear in corners and on ceilings.
Overnight / early morning
Result: Read why mould and condensation appear in corners and on ceilings.
After showers or cooking
Result: Read why bathrooms get wet after a shower.
All year round
Result: Read why the whole house can feel damp even without leaks.
Bathroom or kitchen only
Worst right after showering or cooking
Result: Read why bathrooms get wet after a shower.
Stays damp for hours afterwards
Result: Read why bathrooms get wet after a shower.
Happens even with little moisture use
Result: Read why the whole house can feel damp even without leaks.
Behind furniture or wardrobes
Furniture tight against an external wall
Result: Read why mould forms behind wardrobes.
Small gap but still feels stuffy
Result: Read why mould forms behind wardrobes.
On an internal wall
Result: Read why the whole house can feel damp even without leaks.
Everywhere, most days
Worse in winter or when heating is off
Result: Read why the whole house can feel damp even without leaks.
Worse after cooking or showering
Result: Read why the whole house can feel damp even without leaks.
Feels constant all year
Result: Read why the whole house can feel damp even without leaks.
Explanations (what this usually means)
Wet windows every morning
What’s happening: Moisture builds up in the air overnight and condenses on cold glass.
Common failed fix: A quick morning “airing” that doesn’t change what happens overnight.
Least disruptive start: Reduce overnight moisture, keep background warmth steadier, and improve controlled airflow.
Read next: Why windows get wet every morning.
Bathroom or kitchen moisture spikes
What’s happening: Showers and cooking create humidity spikes that aren’t being cleared fast enough.
Common failed fix: Relying on a cracked window while extraction is weak or not used long enough.
Least disruptive start: Contain moisture during the event, use extraction properly, and clear humidity before it spreads.
Read next: Bathroom condensation after a shower.
Cold surfaces triggering condensation
What’s happening: Surfaces drop below dew point in cold weather — even if the air only feels “slightly” humid.
Common failed fix: Cleaning and repainting without changing surface temperatures or airflow patterns.
Least disruptive start: Stabilise heat, reduce cold draught paths, and improve airflow to corners and edges.
Read next: Condensation and mould in corners and ceilings.
Corners and ceiling edges
What’s happening: Corners and ceiling edges are classic cold spots with weaker airflow, so they hit dew point first.
Common failed fix: Treating mould but leaving the room layout and airflow unchanged.
Least disruptive start: Create breathing space near external walls, keep heat steadier, and improve circulation.
Read next: Condensation and mould in corners and ceilings.
Condensation behind furniture
What’s happening: Trapped humid air sits against a colder external wall, creating a hidden microclimate.
Common failed fix: Cleaning and spraying without moving the furniture or changing airflow.
Least disruptive start: Pull furniture forward, improve airflow, and reduce room moisture load.
Read next: Mould behind wardrobes.
Whole-home condensation
What’s happening: Moisture production, ventilation, and cold surfaces combine — so it shows up across rooms.
Common failed fix: Buying gadgets before fixing the drivers (moisture load, airflow, and surface temperature).
Least disruptive start: Work out which driver is dominant, fix that first, then consider equipment if needed.
Read next: Whole-house condensation.