Single Wall Tents and Double Wall Tents

The most obvious difference between a double wall tent and a single wall tent is the rainfly. The main function of a tent is to keep away the elements like wind, rain and snow and to keep you dry.

For a tent to keep you dry, not only does it need to repel water but also needs to remove moisture on the inside. Moisture can be removed through breathable fabrics and/or a good ventilation system.

A single wall tent keeps you dry by moving moisture away from the tent through its single wall while keeping moisture from penetrating the walls to the inside. It does so with the help of waterproof and breathable fabric as well as venting.

Condensation used to be a major problem for single wall tents but this occurrence has been significantly reduced thanks to better fabrics and improved ventilation system.

Depending on the weather conditions, it may still be a struggle to maintain ventilation to prevent condensation because you may also have to think about climate control especially if you're venting. At times, you may also be letting moisture in through the open door when you're supposed to be venting it.

Price and weight are the main advantages of a single wall tent. Both are a result of having fewer parts. This type of tent is favored by lightweight backpackers, motorcycle and bicycle campers. Another consequence of having fewer parts is that they're also less bulky.

One cool feature of the single-wall tent is that they're set up with the poles on the inside. This may prove to be a useful feature in windy conditions or when it's raining.

While single-wall tents only use one fabric to do the two necessary functions to keep you dry, double-wall tents use two types of fabric. The outer fabric is for water repellency and the inner fabric for breathability or for expelling moisture from the inside.

The outer fabric is called the rainfly and is often made of waterproof material like nylon or polyester. The rainfly may also be made out of breathable material at the same time but its main function is to repel water.

The inner fabric is usually mesh or other fabrics that allow air to flow. When warm, moist air from your breath and body rises and comes in contact with the cold surface of the tent, it cools down and when it reaches a temperature below the dew point, condensation occurs.

The inner tent prevents condensation (at least most of the time) by allowing moist air to pass through it so that it condenses on the fly. If the temperature is above freezing, the condensate will flow down the inside of the fly and drip to the ground instead of the occupants.

If the temperature is below freezing, the moisture will turn solid on the fly and if it drops, will slide on the inner tent to the ground. For this to be achieved, there has to be a separation between the fly and the inner tent and the temperature at the fly is lower than that at the inner tent. Also keep the rainfly tight to avoid chances of condensation buildup under it.

Double-wall tents don't totally eliminate condensation in all conditions but it's less likely to occur compared to single-wall tents. Multiple doors usually present in double-wall tents can help with ventilation if left open and convenient if used as a 2-person tent or more.

The two walls equal more parts and hence more weight but it comes down almost every time a new model is introduced. A double-wall 2-person tent can be as light as 3 pounds these days and will likely get lighter as fabric and tent technology improves.

In dry climates where you're totally confident that there won't be any rain, you can leave the rain fly behind and take only the inner tent to save weight. With just the inner tent, you can watch the stars at night while you keep yourself protected from the bugs. It's also much cooler during the summer with just the mesh tent. You can also leave the inner tent behind and use the rainfly as a tarp tent with an optional groundsheet.