What increases the fuel consumption of your vehicle considerably?

You selected heated seats and the air-conditioning as factors that increase fuel consumption, which is correct. Both heated seats and air-conditioning draw significant electrical power from your vehicle's alternator. To produce this power, the engine has to work harder, which increases fuel consumption. In contrast, the navigation device uses very little power and does not noticeably affect fuel usage. When answering similar questions, remember that auxiliary systems responsible for heating or cooling inside the car are major contributors to higher fuel consumption.