Q. What is condensation?
Answer. Condensation is caused when moisture held in warm air meets a cold surface like a window or wall and condenses into water droplets. If this happens regularly, mould may start to grow. The condensed water usually appears as water droplets or water film on non-absorbent surfaces such as windows or tiles. This is surface condensation. The moisture created can also damage clothes, furnishings and decoration and leaves a musty smell.
Q. What causes condensation?
Answer: Condensation in the home is mainly a winter problem, particularly where warm, moist air is generated in living areas and then penetrates to colder parts of the building.
Water vapour is produced in relatively large quantities from an endless number of activities, from running a shower or bath, boiling a kettle, cooking a meal, doing the dishes and drying laundry all increase the level of moisture in your home. Even something as simple as breathing can add to the problem:
- The use of portable gas and paraffin heaters. Each litre of paraffin burned releases one litre of water vapour into the atmosphere and the use of bottled gas produces even more water vapour.
- The drying of clothes inside the house.
- Steam from the cooking of food in the kitchen.
- Steam from bathing and washing.
- Lack of air circulation within the house.
- A lack of ventilation in the house (which can be worsened by excessive draught proofing).
All houses are affected by condensation at some time. It usually occurs when a lot of moisture and steam are produced e.g. when cooking, having a bath or shower, washing clothes, or after a cold night when bedroom windows will be misted up.
Q. Should I be worried by condensation?
Answer: One of the consequences of condensation is mould growth. Mould will appear on any damp surface such as plaster, wallpaper and timber and is associated with the condensation problem of many buildings. It is unacceptable because of its appearance (unsightly growths of various colours - greens, yellows, pinks, black, grey or white), odour (musty and damp), fears of health and hygiene considerations.
It is a proven medical fact that black mould can cause respiratory problems and condensation and dampness can aggravate asthma suffering as well as causing mental distress. It is therefore vital that black mould is cleaned off and condensation problems eradicated as quickly as possible.
Q. How can I minimise condensation within my house?
Answer: By taking the following steps you can, in many cases, reduce and possibly eliminate condensation within your house:
You are strongly advised not to use portable gas and/or paraffin heaters within your house.
Use extractor fans for ventilating kitchens and bathrooms and keep the doors on these rooms closed to prevent moist air circulating throughout the house.
Avoid drying clothes in your house.
Keep furniture such as beds and wardrobes clear of walls to permit air to circulate.
The use of background heating, dehumidifiers and trickle ventilation, especially in winter, will reduce condensation.
Q. What does a dehumidifier do?
Answer. The way a dehumidifier works is similar to the way the condensation forms on a cold window. A dehumidifier contains a compact refrigeration system that makes it the coldest place in the house. Air is drawn into the cold dehumidifier where any moisture in the air condenses on the hydrophilic coils and is collected in the easy to empty container.
So, if you regularly see condensation on your windows, or damp and mould spots in the corners of cold or little used rooms, the air in your home probably contains excess moisture. If you don't do anything about it, this moisture can damage your carpets, curtains, furniture and even your walls. You should consider using a dehumidifier to remove this excess moisture before it becomes a serious problem.
Q. How much water can I expect to take out?
Answer. 90% of homes can produce 3- 5 pints per day, but every home is different. For example, it's not unusual to find next door neighbours in almost identical homes with the same family size producing different amounts of moisture. There's no hard and fast rule about how much moisture to take out, but you will soon know if your dehumidifier is working effectively as condensation will start to disappear and your home will feel much drier and healthier.
There are other unseen benefits too, including a reduction of moisture levels in your furnishings and walls, less mould and fungal spores and fewer house mites – all of which can provoke allergies.
You might also find that your laundry dries quicker with a dehumidifier in your home, which is a welcome benefit in winter or if you live in an apartment that has no outside drying space.
Q. Do I need to run a dehumidifier all year round?
Answer: Running a dehumidifier from early October until the spring is generally sufficient as more moisture is generated during the winter. It's also better to start using your dehumidifier before the winter starts, this reduces the risk of moisture soaking into your walls. If you do start your dehumidifier part way through the winter it is advisable to run it continuously for around 2 weeks to ensure your home is properly dried out.
Q. What if the dehumidifier dries the air too much?
Unless your settings are wildly incorrect, this simply won't happen. If there is no more moisture there the dehumidifier can't collect it.
Q. What is the difference between dampness and condensation?
Answer: Dampness occurs when a fault in the basic structure of the building lets in water from the outside.
There are basically two types of damp:
Penetrating damp.
Penetrating damp occurs if water is coming in through the walls or roof, for example, under a loose roof tile or through cracks on the outside wall of the house. The usual signs are mould, a musty smell and wet patches on the walls or ceiling after rain.
Rising damp.
Rising damp occurs if there is a problem with the damp proof course; the barrier built in to floors and walls to stop moisture rising through the house from the ground. The usual evidence of rising damp is a "tide mark" on the walls. There can also be a musty smell.
You should attempt to recognise the difference between dampness and condensation and if you think that your house is suffering from either rising or penetrating damp, you should seek expert advice.