Wireless Doorbells Explained
Wire free doorbells have a bell push button which generates a wireless signal when the button is pressed. This signal is detected by an internal doorbell and will ring for a set length of time. There is no limit to the number of wireless units placed around a property, since each is just detecting a signal. Most wireless doorbell units can detect at least 2 individual bell push buttons and if the unit has at least 2 sound options, then a different sounds can be made, dependent on the button pressed, i.e. “front door/back door” operation.
UPVC & Metal Frames: Wireless signals cannot pass through metal, and therefore UPVC doorframes which are generally supported by a metal frame for strength and security should be avoided. Where UPVC doorframes are installed, it is better to position the bell push on a wall to the side, or on the door, if it is a composite type. If a short length of wire can be inserted around a UPVC doorframe to the inside, then a wired to wire free extender may be a solution.
Signal Strength: The standard distances, 50m, 100m, 150m and 200m refer to the distance a chime unit will detect the signal from a bell push button in “open field conditions” i.e. without any walls etc to interrupt the signal. “Open field conditions” is a standard that all manufacturers use rather than saying “Typical” distance. We consider the 50m chimes to be short distance for reception areas of a modern property with the bell push on a wooded doorframe. A 100m chime may be considered suitable, when the bell push is placed on a wall, or the doorbell is placed further in the property. A 200m chime would be more suitable for large properties with thick walls, or as portable units to take into the garden, or possibly, for a doorbell unit in a “Garden Office” (depending on the fabric of the office). If used in an external office, then the walls of the office should not be insulated with foil backed insulation, or there should not be foil backed insulation in the main wall cavities of the main property. Grothe now supply their Mistral models with standard distances of 250m and 500m which can be extended even further by wiring additional bell push buttons into the receiving chime unit.
Batteries: All wireless bell push buttons have an internal battery, mostly coin sized units code CR2032. If the bell push is pressed once a day, then this battery will generally last about 2 – 3 years. If the bell push is pressed 10 times a day, as say in an office environment, then batteries will need replacing every 2 – 3 months. As the battery voltage weakens, the signal strength deteriorates. If a visitor cannot hear the doorbell from the outside, there is a tendency to press the button repeatedly and therefore reduce the battery duration. Re-chargeable batteries should never be used in battery door chimes since the voltage on full charge of such an AA battery is at a maximum of 1.20v compared with the value of 1.50v of an AA alkaline battery. With a battery voltage of 1.20v, a wireless chime will have limited effectiveness.
Plug-in Doorbells: There is the option of a plug-in doorbell, where the unit is plugged into a socket. Some units, where the frequency of the chimes are set be switches, can be removed from the socket, and replaced without losing settings. However many chimes are setup by “auto-detecting” the frequency of the bell push button, and these should not be removed from the socket after setup, since settings will be lost. They can of course be reset if necessary.
Wired to Wire-Free Extenders: Most bell pushes for wireless doorbells are plastic, or plastic with metal fronts. Exceptions are 2 models from Friedland in the Evo and Decor range. If you wish the bell push button to be a more traditional wired type, then these can be linked to a wired to wirefree extender to generate a wireless signal. These extenders are designed to be internal products, and therefore need to be linked to the outside bell push by a small length of wire. The extender can be used as a wireless only system, or be linked into a wired system as an extension, so that both wired and wireless doorbells ring at the same time.