It’s early October and the weather is unseasonably warm; certainly too warm to switch on the central heating – especially with fuel costs as they are. But we can feel the onset of winter in the early mornings. We’re hearing reports that the most common reason for calls to Healthy Homes Dorset at the moment is because of damp being experienced in the home.
Here’s the technical bit.
The air that we breathe contains a lot of water; it’s what keeps us alive (among other things). The amount of water that the air can hold depends on the temperature of the air; the warmer the air, the more water moisture it can contain. But should that air cool – say, when it comes into contact with a cold window first thing in the morning – it can quickly reach saturation point, the water separates from the air and settles onto the cold surface.
Where does the water in the air come from? Well, that’s from you and me. We may breathe a lot of water in , but we also breathe a lot of air out. And we perspire. Our bodies are designed to keep our internal temperature stable’ air flow across the skin helps shift water from the skin and cools us in the process.
We also engage in processes that involve water; we cook food; we wash / shower; boil kettles. All of that activity will put water vapour into the air.
On one hand, we produce water vapour – and, at the same time, we try not to turn on our heating systems.
What can we do?
Ridgewater Energy has produced a leaflet How to Prevent Condensation, Mould and Damp in your home.
Top tips for reducing water vapour:
Dry clothes outside whenever possible or make sure that tumble dryers are properly ventilated.
Keep bathroom doors closed and open windows partially for at lest an hour after bath or shower.
Keep bathroom doors closed and run the extractor fan, if fitted.
Don’t use paraffin or bottled gas heaters as they will produce 8 pins of water vapour for every gallon of fuel burned,
Keep air moving and as fresh as possible. If you have trickle vents, use them.
Avoid having furniture hard against outside walls.
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But we have to rely on warm air to really control condensation.
Walls act as a thermal store, depending on how they are built and what they a re built from. The key is to keep walls above the temperature where water vapour in the air condenses onto the wall surface – this is know as the ‘dew point’. And it’s a vicious circle; once condensation forms, walls cool down even further, leading to yet more condensation.
This may sound counter-intuitive, but running heating for short bursts can actually create more condensation. The warmer air draws in more moisture – which then condenses onto cold surface as the air cools down again.
And don’t get too enthusiastic about ventilating rooms if you’re not at home. Ideally, you want to maintain temperatures stored in the fabric, even while the air temperature is cooling. Again, trickel vents an provide you with the fresh air that you need, without drafts chilling the space unneccesarily.
Where does mould come from?
Mould spores are opportunistic and will try to latch onto damp surfaces. As the spores grow and develop they become the black spots that we’re familiar with in our homes. Mould is dangerous to our healtth and can cause lasting damage. We’ve all heard about fatalities caused by breathing in the spores from black mould.
Removing mould is a hazardous process i itself and products need to be approved under the Control of Pesticides Regulations.
If you experience mould in your home:
- avoid vacuuming or brushing off the mould as this can release spores into the air.
- mop-up any excess water from windows, sills and frames.
- dry clean any clothes that have been affected by mould.
- Always follow manufacturers’ guidelines when using any product.
Ventilation and draught proofing:
Rooms need fresh air but we also want to avoid draughts. Its a fine balancing act but is very important. The tendency is to treat any moving air as a ‘draught’, but it may be because we’re sitting too close to a healthy ventilation point. If you can, move your furniture so that the fresh air can tumble into the room without anyone feeling uncomfortable
Finally, treat your home as a dynamic thing; it does different things in summer and winter. Our relationship to the rooms where we live can’t be throughout of as constant throughout the year. A rug on a stone floor in winter can keep our feet warm, but the same rug in the summer can stop the cool radiation from the floor that we need to keep temperatures down.
In all of this, we have to consider the cost of staying warm and healthy. If you are struggling with fuel bills, or your overall household economy, then contact Citizens Advice who can guide you through the options that are available to you.
