How is condensation caused at home?
We all generate lots of water vapour which is invisible and odourless. Up to 2 gallons a day for the average family.
Steam is obvious but it becomes invisible water vapour almost instantly – steam from a kettle disappears but is still there as a gas. Unfortunately the water vapour moves around the home and condenses on cold windows, walls, leather and clothes when the house cools down each night.
Every morning the steam from yesterday’s shower is streaming down your bedroom windows and growing mould on your wallpaper, curtains and your children's shoes.
FACT – Water vapour evens itself out throughout the home. Steam from a shower can condense in the corner of the spare bedroom 40 feet away. See Boyle's Law if you want to find out why.
Why is condensation a problem?
Black spot moulds need food from wall surfaces and moisture. The more dampness the better they grow. Moulds can destroy wallpaper, leather, timber and fabrics. In worst cases this causes £1000’s of damage each year.
The drudgery of sponging windows each morning is a waste of time.
House dust mites need moisture in the air which they absorb. Millions of microscopic dust mites infest damp homes. Mites eat a variety of food around the home. Mites are responsible for many allergic responses – up to 80% of allergies are affected by mites.
Bed bugs do not drink - they absorb water from the air so reducing humidity will reduce bed bug population.
Damp conditions are associated with poor health especially asthma – correlation between poverty and allergic responses due to condensation.
Damp air needs more energy to heat. Dryer air ‘feels warmer’ at a lower temperature - control damp and reduce your energy bill.
Wet rot. Condensation can dampen timber allowing wet rot spores to germinate and wood weevils to thrive.
Wet insulation is ineffective and increases heat loss. Usually this is a hidden problem.
Musty smells make the home unpleasant to live in........
How to reduce condensation yourself?
It is almost impossible for most families to get the humidity low enough to stop condensation: you can't stop washing, cooking or breathing. Here is some advice I hope you will find useful.....
Dry clothes outside whenever possible.
Open windows and doors when possible.
Put lids on cooking pots or use pressure cookers.
Shower less frequently and/or for a shorter time.
Throw out fish tanks, house plants and pets!
Run bathroom and kitchen fans for long periods to expel the damp air.
Use cooker hood (if vented outside) when and after cooking
Condensing tumble dryers or vented driers will help.
Do not use bottled gas to heat the home - it creates a lot of damp.
Condensation Control Systems that work
POSITIVE PRESSURE UNITS. PIV. PPU. ACU.
Cheap to install (competent DIY) – cheap to run - automatic and extremely effective – solar gain to heat the home - dry the whole house with one unit in the roof. The best choices are available in our store.
HEAT RECOVERY VENTILATION. HRV.
Very cheap to run - fully automatic - ideal for flats with no roof void - extremely effective - perfect for bathrooms and kitchens where most of the damp is generated - quite running - conform to FI Building Regulations -
HUMIDITY COTROLLED FANS. HCF.
Cheap to buy and install
– easy to swap for old fan - cheap to run - automatic. Set to about 65% to ensure it runs a lot - a first option on limited budget.
How not to control condensation?
– Very expensive to run – noisy - need emptying – take up floor space – only reduce humidity the immediate area - produce lots of distilled water. They can sometimes help with a minor problem in a remote room. Borrow one - there are lots about not being used because they don't work.
Draught proofing. It is lack of air that causes condensation.
Double glazing. Makes the home 'tight' and often increases condensation.
Cavity wall insulation, and loft insulation – will not combat humidity – some 'improvements' make condensation worse by making the house ‘tight’ - Insulation reduces heat loss only.
Anti-condensation paints. Essentially these are formulated to be poisonous to moulds and will do this job well. A cup of bleach with a gallon of water will also kill black mould just as well! However poison will not reduce the condensation: it will only kill black mould for a limited time. The windows will still get wet, moulds will grow on clothes/shoes and dust mites will thrive.
Air bricks in walls – do you want to live in a wind tunnel? – Air bricks are only installed to ventilate roofs and timber sub floors.
Make the home hotter – Self-defeating - the air will then hold
more water - it is a waste of your money – heat can make the problem worse. Damp air feels colder than dry air and costs more to heat.
Water proof the outside of the house – please re-read the page starting at the top. Paint will stop penetrating damp only