3 factors that influence the range of your wireless doorbell
1. Concrete walls
Manufacturers always measure the range of a doorbell in the open field. On such a reading, no interfering elements are present that limit the range. In practice, that's different of course. Take, for example, the concrete walls in your house. The thicker the concrete walls in your house, the lower the range will be, since concrete walls contain metal that affects the range. Apart from the thickness of the walls, there's also your house's insulation. The better insulated the house, the worse the range between wireless elements gets.
2. Wireless devices
You have a lot of wireless devices at home. These devices or sensors are connected to each other over a frequency, WiFi and Bluetooth. The advantage to this is that there are no cables lying around. The disadvantage is that all wireless signals are running together, which means they interfere with each other and also with your doorbell's range. For this reason, don't place various wireless devices (that don't need to communicate to each other) too close together in the house.
3. Other signals in and around the house
Apart from wireless signals, you also have a lot of electrical appliances in your house that emit radiation. This radiation disrupts your wireless doorbell's signal. Take for example the microwave or the television. You don't notice it, but the appliances continuously emit radiation. When too much of these signals are running together, their general range decreases. Just as with wireless devices, don't place electrical appliances too close together.