Condensation can be a problem when you are using your bivvy for long periods, and especially overnight. One thing we will say is this: don’t believe a manufacturer who claims their bivvy will not be subject to condensation, as it is simply part of nature!
It happens when warm air comes into contact with a colder surface: think of your bathroom mirror when you have a shower. That’s condensation, and when you have a combination of cold bivvy walls and warmer air – perhaps provided by you breathing or by warming the air with a heater – you have condensation.
Condensation is always going to happen in a bivvy – or indeed a tent – but there are some things you can do to lessen the problem, so let’s have a look at them.
Keep Wet Clothes and Shoes Out
One of the keys to combatting condensation is to keep damp things out of the bivvy, and this includes wet clothes and footwear. If inside, they will only add to the moisture that is already present and simply make things worse. Remember to keep them safely outside – and covered – so they don’t get wet again when it rains, or if you’re not going to dry them during your visit, put them in a bag.
Keep Vents Open
Keep your rain fly open, and any other vents that you may have on your bivvy, and if possible – and comfortable – keep the door open too. Constantly circulating the air in the bivvy is vital if you are to keep condensation down, and makes for a more comfortable place to be.
Boiling water in the bivvy will simply add to the moisture; if you are cooking, do so outside the bivvy and keep the steam away. If you can’t cook outside thanks to the weather, why not invest in a cheap second bivvy for this purpose only? It could also be the place to store those wet clothes, shoes and bags we talked about!
There is a great deal to be said for pitching your bivvy away from a water source, but when fishing this is not possible. The above tips should go some way to helping you combat the condensation that will occur during your trip, so make sure you concentrate on ventilation and keeping wet things outside, and you’ll be in the best position.