Condensation occurs when water vapour is converted into liquid water. If the air temperature drops, at night for example, some of that moisture will be released when the warm air comes in contact with a cooler surface like a wall, ceiling or window pane and then droplets of water form on the surface. This contributes to mould growth and makes houses feel colder and more difficult to heat. Mould is also a trigger for asthma.
Our daily habits create a cycle of condensation – even morning showers and cooking breakfast produce water. Ventilation is important for reducing and controlling condensation. Fortunately it takes just a little effort to do this. The cheapest and most effective method is to have windows open a small amount over long periods of time. (Security concerns can be addressed through fitting security stays or fitting aluminium windows with passive ventilation and condensation channels.) Externally vented extraction systems in the kitchen (range hood) or bathroom (extraction fans) will reduce moisture levels significantly. Close doors to the bathroom or laundry if large amounts of water vapour are being produced so that it doesn’t spread throughout the house, and open the window in those rooms to allow water vapour to escape
Portions of this were sourced from BRANZ Bulletin 367 “Condensation”
Damp homes can cause health problems for the people who live in them, and they are more difficult to heat. It is important to try to identify the causes of the dampness and correct them. If a home is insulated, ventilated and adequately heated but dampness and mould growth continue, it is likely that moisture is coming from damp ground beneath the floor, from rainwater leaking into the home, or from leaks in plumbing.
Many of our homes were built before insulation was required to be installed and unfortunately many homes were never retrofitted with insulation. About 40% of heat can escape through an uninsulated roof and 10% through an uninsulated floor. No curtains or badly fitted curtains also allow heat to escape. Similarly, gaps under doors or around windows also make it hard for us to heat our home. Many people just give up trying to heat their home adequately because with all the ways in which heat can escape, but these problems can be fixed.