Why Condensation Forms on Windows and How to Stop It
On a cold Sydney morning, many homes wake up to water streaming down the inside of the windows. It looks harmless, but persistent condensation is a sign of heat loss and a leading cause of window-frame mould.
The physics, briefly
Warm indoor air holds moisture. When that air touches a cold surface, it cools and releases the moisture as water. A single glazed aluminium frame is exactly that cold surface: the metal sits close to the outside temperature, so the room-side face gets cold enough for condensation to form on it every cold morning.
Why it matters
Beyond the nuisance of wiping windows, that moisture feeds mould in the frame reveals and on nearby walls and curtains. In a strata building it can become a shared maintenance problem across many units. It is also a clear signal that the same windows are letting expensive heat escape.
How to stop it
- Insulated uPVC frames stay close to room temperature, so the cold surface that triggers condensation is largely removed
- Double glazing keeps the inner pane warmer than the outside air
- Good ventilation and, where fitted, tilt-and-turn hardware let you air rooms without losing all the heat
Condensation is not something you have to live with. Replacing cold single glazed frames with warm, insulated double glazed uPVC removes the surface that causes it, protects the building from mould, and confirms the heat is finally staying inside.