Since a wireless signal travels through the air, it may be impeded by obstacles between the transmitter (the router) and the receiver (e.g. a computer). These might include walls and ceilings. In particular, concrete with steel reinforcement may have an adverse effect on the range and quality of the signal.

Household appliances, such as DECT phones or microwaves, may also affect the speed of wireless networks. These devices operate in the 2.4 GHz frequency band, which is the same standard that most routers use.