Condensation is telling you something – you just need to listen

Condensation and mould are a terrible problem for loads of homeowners and tenants:

·      It makes it hard to keep the house warm

·      Clothes, books, bedding – it all gets damp and covered in mould

·      Air quality is terrible, especially for anyone with respiratory problems

And it’s so hard to get rid of. Dehumidifiers work to a degree, but they cost in electricity. So what else can you do?

First of all, why does it happen?

It’s all to do with the temperature of the air and the amount of moisture floating around your home. The warmer the air, the more moisture it can hold.

This will surprise you: A family of four produce 20 litres (that’s 42 pints) of moisture a day, just by living. Breathing, cooking, drying the washing, showering, sweating – the list goes on. And it’s all got to go somewhere.

If your home is cosy and warm then the problem is a bit less because the warm air will be able to hold onto some of it. But you do still have to find a way to deal with it.

If your house is cold, then it’s a big problem for you. As soon as the air hits a cold wall, it cools down even more. The moisture load is dropped and it starts dripping down your walls.

You have two choices: you can change the air or you can reduce the moisture.

Let’s think about tenants

If you live in a rental property, it’s unlikely you can make any fundamental changes to the place. So you need to focus on what you can do immediately to improve your situation.

The problem arises in part because we want to reduce draughts – of course we do. We want to be warm and also to save money on energy bills. And for good reason – staying comfortable and dry is a very expensive business.

So we add draught excluders to doors and windows, close up chimneys, put rugs down on windy floors – anything to reduce the amount of cold air coming into the home. The downside is that the draughts have done a pretty good job of getting rid of excess moisture.

So what can you do?

Keep the air moving: take every opportunity to change the air in your home. Let the old air out so it can take the moisture with it and bring fresh air in. I know it seems daft if it’s raining outside, but it will still drier that your inside air that’s loaded with those 42 pints

Trickle vents: these are small grills that sit at the top of your windows with the intention of bringing in fresh air. The temptation is to cover them or leave them permanently closed because they send a draught down your neck, but they will help stop condensation. If the draught is really bad, then close them off for a time and open them up when you’re not sitting beneath them.

Shock ventilation: this is a good habit to get into. It’s automatic in many European countries I’ve learned – they grow up with it.

Start in your bedroom and open up a window. Then move to the next room and open a window. Do this in each room of your home. When you get to the end, go back to the beginning and close them all in the same order.  It gives a reasonable time to change the air without losing too much of your heat. Do this twice a day and it will help cut your condensation.

Dehumidifiers: these help by removing moisture from the air. They do use some electricity, but they will also give you some heat which can be helpful.

Dehumidifier bags: If you get condensation on your windows these bags help. They are full of moisture absorbing crystals so you just put them on your window ledge and they get rif of the condensation for you. They change colour when the crystals are saturated, so you just pop them in the microwave to dry out and use them all over again.

Increase the warmth: if you do this the air will hold more moisture, but my guess is you’ll already have put the heat up as much as you can to suit your level of comfort or budget.

Then, let’s think about homeowners

If you own your home then you have much more choice in the matter and you can make a real difference to condensation.  

BUT: this is one of the big mistakes people make when renovating or improving the home. They forget to factor ventilation into the plan. Even if they think about insulating their home for energy efficiency, ventilation is likely to be low on the list or even off the list altogether.

When you insulate your home and make it airtight, you are taking out all the uncontrolled air. Air that has previously changed on a regular basis taking excess moisture with it. Now you’re warm but you are essentially sitting in a sweaty box.

So now you have to add back in controlled air. Both so you can breathe easy but also so you keep your house dry. There are different ways of doing this, from full house systems to single room ventilation units. You can get straight forward vents or include heat recovery to reduce your costs. You can read more about the options here.  

In summary: the trick to reducing condensation is getting the balance right between moisture and warmth. It is also about free flow of air so the moisture doesn’t sit in any one place for too long. It can be done – and easily if you own your home.

Just make sure it is high on your list of priorities. And don’t expect the builder to tell you about this – the most they usually suggest is trickle vents.

If this makes you think: ‘I need to understand more about this or I’ll end up making decisions I regret’, then go look at my latest book: What the Builder Won’t Tell You for loads more information. Any other questions, let me know.