The benefits of keeping the dryer close to an outside wall will far exceed the benefit of having a dryer situated in the middle of the house. A lot of homes today have home style residential dryers situated in the middle of the house. This can provide a benefit of having the dryer accessible but it requires a lot of exhaust pipe to be used and routed through wall to meet its termination exhaust point on the outside. Often the exhaust pipe requires more than 15 feet of exhaust pipe to reach the termination point
The long exhaust pipe will eventually create an exhaust problem and possible fire hazard for the home. Residential style dryers are not designed to have to exhaust air more than 15 feet to the termination point. When exhaust pipes are fitted through walls they often have 90 degree turns in the piping . This creates friction drops and the air is not able to exhaust as freely as it should. When you factor in
elbows and long lengths of exhaust pipe you will have a considerable friction drop across the exhaust system. When this happens dryer lint starts to build up in the piping. Eventually the pipe will plug up and the dryer will take a considerable long time to dry the clothes. This is where dryers start to overheat and fires can start at this point.
It is a good idea to clean out lint traps regularly. Check to ensure that the outside grill (termination point ) is not plugged and a regular cleaning of the dryer duct will also make the dryer more smoothly requiring less energy to operate.