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Eight Expert Tips to Master Mould

Air quality expert Stuart Smith writes

The average family produces 24 pints of water vapour a day through routine activity but many think opening windows and turning on extract fans, which would help extract the moisture, will make their homes too cold, so don’t.

People often complain of feeling run down in the winter with tickly coughs, stuffy noses and dry or itchy skin and these are all symptoms of a bad indoor climate, not just the common winter cold. Left unchecked damp and mould can do serious harm.


In a home, a little condensation may not seem like a big deal, but the truth is, it's a silent indicator of potential trouble.

Ignoring this seemingly harmless moisture build-up, like many do – with one in 10  opting to just paint over mould breakouts - can pave the way for a host of larger issues.

Why does condensation occur and why is it bad? Condensation occurs when warm, moist air meets cooler surfaces, for example a steamy bathroom and cold windowsill. This is particularly prevalent in winter as temperatures drop, windows get closed and households turn on their heating. 

The excess moisture in the air quickly condenses and homes are at risk of condensation. This all contributes to increased humidity in a home’s indoor air and without adequate ventilation, this moisture gets trapped and it creates the perfect breeding ground for mould, which can be toxic.

Keep extract fans turned on – many think extract fans in kitchens and bathrooms make the house cold but that’s a myth, they work to reduce moisture in the air. Be sure to check and clean the vents regularly – a hoover and dust once or twice a year should keep them in good working order. 

Maintain a consistent climate – keeping a steady temperature throughout the property is key to avoiding condensation and outbreaks of mould. Avoid drying clothes indoors where possible and use extract fans in kitchens and bathrooms to remove steam from cooking and bathing.  

Upgrade home ventilation – check the age of the extract fans in your home. If they are over 10 years old they might need replacing. Fan technology has come on massively and you might find a newer model will give better performance and efficiency. 

Give your radiators some love – like a boiler, the rest of your home heating system needs annual maintenance too. When the heating is on check all radiators are hot from top to bottom. Cold at the top and they might have air inside and need bleeding, cold at the bottom and they might be full of sludge and need flushing by a professional. Keeping them working properly could save £50 per year on heating bills and maintain better heat output for the house. 

Catch breakouts early – if you see any mould on walls or window frames tackle it as soon as possible. Wash down the affected area with warm soapy water, leave to dry then treat with a mould and mildew spray or fungicidal wash to kill the spores. Don’t just paint over it or ignore it as it will come back or spread uncontrollably. Good ventilation is vital to prevent future problems. 

Keep refreshing the air – getting fresh air in and moisture out is key. As often as possible, open all your windows for as long as is reasonable. This will reduce humidity that leads to condensation and mould. Try to do this before you put the heating on so that it warms the fresh air not the stale air.

Avoid build-up of CO2 and humidity in bedrooms / living areas – when all snuggling up in the same room, carbon dioxide can quickly build up, making inhabitants feel sleepy and, in some cases, sick. It also creates excess humidity leading to condensation and damp. Having a window open – even a little – will help to extract the stale air and lower the humidity levels, meaning occupants aren’t rebreathing each others’ breath.

Invest in moisture-guzzling plants – house plants like Peace Lilies, Snake and Spider plants, Aloe Vera and Boston Ferns have been proven to reduce humidity in rooms and also have air-purifying qualities, so are an all-round indoor air quality improver. 

Stuart Smith is indoor air quality expert at heating business Zehnder 

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    Fit a Nuaire Drimaster 'Heat' Positive Input Ventilation (PIV) fan and the problem goes away. Fit a tamper proof cover over the ON/OFF switch from SSP Direct. That's what I've done in every rental unit I own and my own office as well.
    Social landlords have installed Nuarie PIV fans in thousands of their units. It's very hard for a tenant to mount a successful claim if you are EPC Grade C and have installed a PIV fan.
    It's common sense.


    Gibbo is off again. Someone give him an EPC to play with.

    As for "Social landlords have installed Nuarie PIV fans in thousands of their units" IF that is true and it is a BIG IF, why is there a firm called thedisrepairlawyers advertising on television for tenants of social landlords who have damp and mould to contact them? Are they perhaps seelling PIV or after a cut of the compensation?

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    Most landlords use the Envirovent model which comes direct through Envirovent themselves, where they use a proper technical representative to do a professional survey before making their recommendations. They also provide a service and maintenance service ongoing. I once used a Nu Aire unit which are supply only and you have to find your own installer. I would normally have installed it myself as a retired HVAC technician, but as I live abroad I had to rely on the local "expert" who made a complete mess of it. If you want a proper guaranteed istallation by a professional company use Envirovent who operate nationally. Also much of Envrovent's clients are local authorities and housing associations and they should not be confused with double glazing type cowboys.


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