How to reduce condensation in a tent

NOTHING puts a dampener on a camping trip quite like waking up in the middle of the night in a wet sleeping bag with water dripping around you.

And, while some degree of condensation is completely inescapable, there are several measures you can take to reduce the amount.

First of all, though, you have to understand that even the greatest explorers using the absolute pinnacle of tent technology still experience condensation. It can only be lessened – it cannot be eradicated.

The reason for this is down to the fact that you are the cause of most of the moisture in your tent. After all, we are all made of 60% water and, therefore, cannot help but produce moisture.

The average person will emit something like one pint of water simply through breathing and evaporation during the night.

Imagine, then, there are three of you in a badly ventilated tent. That’s three pints of water sloshing around somewhere – being soaked up in your sleeping bags and clothes, or simply dripping from the inside of your tent.

Add to that any moisture in damp clothes or boots kept inside – plus the natural occurrence of moisture in the air (a space the size of a three-man tent will, in normal atmospheric conditions, contain roughly half a pint of water in the air alone) – and you’ve got a potential river to wake up to.

Severe condensation

If the outside air temperature is much cooler than the inside temperature – particularly if it has experienced a significant fall from a hot and humid day – then condensation inside the tent will almost certainly be at it its worst.

The material of the outer sheet will also cool, quickly attracting moisture to both sides of the fabric.

Rain during these conditions will make things significantly worse – not because your tent is leaking, but due to the effect it has on the temperature of the fabric.

Tips for reducing condensation…

Condensation tips
  • If it’s a cold night, the temptation will always be to lock yourself in tight and shore up any draughts. But, even in the most severe conditions, you will benefit from having as much ventilation as possible. Ensure you make the most of a good sleeping bag to keep you warm, rather than compromising on ventilation which will likely lead to making your situation worse through extra condensation.
  • Keep a couple of muslin cloths in your pack for the purpose of mopping up moisture in the tent. They are easily wrung out and dried.
  • Gently wipe the walls to prevent drips, but always ensure you do not allow the inner wall to touch the outer layer as this will almost certainly lead to seepage – particularly with polycotton. You can always help your case here by regularly checking on guy lines to keep the outer sheet clear of the inner.
  • If your tent is wet, and you are staying in the same location for a while, take the opportunity during the day to fully open the inner, and remove the outer sheet to dry out (if it’s only wet on the inside of the fly, it is possible to turn it over and put it back over the frame of some tents). If rain is an issue, leave the fly in place or, if you have one, create a canopy with a tarp.
  • If you are moving on to a new camp, wipe off as much damp as you can before packing the tent wet in a liner, and make the most of rest stops on your hike to get the tent out to dry. When reaching your next camp, pitch the inner fully unzipped, and place the outer somewhere it can have a good airing.
  • If the atmospheric conditions look likely to cause condensation, try to avoid total shelter from the wind (here’s a guide on how to pitch in high winds). Instead find a semi-sheltered area that will provide a reasonable breeze to help remove moisture and create a draw from the tent’s vents. Keep as many of the vents open as possible and, in good conditions, consider opening up the top of each door zip to aid airflow.
  • Despite the temptation – particularly when it’s -10C outside – avoid using heaters or cooking in your tent. Science dictates that raising the temperature inside your tent is a sure-fire way to guarantee waking up in a damp sleeping bag with water drops bouncing off your forehead.
  • Use a tarp or makeshift shelter – or awning if necessary – to stow any damp bags, clothing or boots. Try to avoid having them in the sleeping space with you as these will increase the amount of moisture in the air and only add to the condensation problem.
  • If you’re on a canoe camp, try to pitch at least five metres away from the water. Moisture in the air is well concentrated close to the water source, and humidity will be at its greatest.
  • When camping close to water, make sure you camp on slightly higher – but not exposed – ground. The water table around the water source will pool humidity and moisture into the natural dips and bowls of the landscape.
  • Pack spares. Condensation is largely unstoppable, so keep a dry set of clothes and a spare towel on longer trips in case the weather or circumstances won’t allow you the opportunity for drying your tent and your belongings out.

A message for all outdoors beginners and novices…

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