Dryer vent hoses can become damaged for any number of reasons. Most of them are made from plastic or flexible layered aluminium, which resembles tinfoil. While the soft and bendable nature of dryer hoses makes them easier to install and fit into confined areas, it also makes them more susceptible to punctures and tears.
Measure the distance from where the vent comes out of the back of the dryer to where the outside vent meets the wall. You need to measure this when the dryer is in its operating space. When you attach a dryer vent hose, you do not want to have a lot of extra hose, as this can cause lint and debris to be easily trapped and plug up the hose.
Take the distance that you measured in step 1, and add 2 inches to it. The additional 2 inches ensures that the dryer hose is not cut too short. Measure that length of the dryer hose; then cut the hose with household shears or a utility knife.
Unplug the dryer before doing any work to it in order to prevent the possibility of an electrical accident.
Pull the dryer out of position in order to disconnect and attach the new hose.
Disconnect the old hose from the outside vent nozzle. Most dryer hoses are clamped on to the dryer hose nozzle with either a standard clamp that loosens or tightens with a small screws, or a clamp that can be pinched with your fingers to loosen. If you have the older, screw version, take a flat head screwdriver and loosen the clamp. Otherwise, loosen the clamp by squeezing the ends together with your fingers.
Disconnect the old hose from the back of the dryer and discard it.
Place the clamp around the end of the new dryer hose; then slide the end over the dryer hose vent that vents outside. Tighten the hose clamp, if necessary.
Slide the dryer in closer to the outside vent, so that the hose will reach the vent nozzle easily. Slide the hose over the nozzle, and tighten the clamp if necessary.
Move the dryer back into position and plug back in to the power source.
If you are nervous about cutting the dryer hose to fit, just make sure that it is not bent or crimped when you put the dryer back into position.
Measure twice before cutting the dryer hose to fit. If you cut it too short, you won't be able to piece it back together. Avoid using plastic dryer hoses, as they are a fire hazard. Choose the foil type hoses instead.