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Ventilation of your property and condensation


Do you remember times before houses were packed with loft insulation, before cavity wall insulation and double glazing? Houses with single glazed windows had ice on the inside, draughty floor boards and a howling gale that came through the windows and doors, the “central heating” was a fire place or a range!

As we drive forward with more energy efficiency, better insulation, draught-proof windows, doors and floors we have sealed up our houses, at the same time made our homes warmer than ever before.

Modern living has resulted in people living in smaller spaces with tumble dryers, radiators, house plants and more showers/baths. All these add moisture to your home – this creates a dramatic increase in warm, water laden air.

For security and insulation reasons, we also don’t leave our windows open. Why spend money heating a place to open windows and have that cold air flow in and the hot air rush out?

The result is a developing problem in modern houses. we have a problem with condensation, mouldy walls. Mould around windows, peeling paint around windows, a line of mould on the wall/ceiling line.

This is the reason trickle ventilators were specified in building regulations in the 90's. All new builds and extensions had to be fitted with trickle vents. Today there are Positive Input Ventilation Systems which can be installed but window trickle vents are a cheaper and easier option.


So if you are thinking about replacing your old windows which already have trickle vents, your new windows will need to have them too (assuming they were required under the original building regulation requirement when they were installed) The new vents should offer at least the same capacity as the existing outgoing vents.


What creates the biggest problem?


The most common contributors to high levels of water laden air in the home are towels on radiators, showers and boiling on the hob.


Simple steps can be taken to help.


  • Following a shower open the window and close the door to the bathroom. Let the air circulate in the bathroom and the water laden air will be replaced with fresh air. This saves all this moisture spreading around the house. 

  • Boiling on the hob – install and then use an extractor fan, as you see the water levels decrease in the pot all the water is circulating around your house without and extractor fan. 

  • Towels on radiators create large amounts of moisture which becomes airborne. Open a window directly above the radiator to allow the moisture filled air to be replenished.

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