Can I Use My Honeywell Security System to Wirelessly Monitor My Home's Temperature?

Yes, you can use your Honeywell Security System to wirelessly monitor your home's temperature. This is possible using a temperature sensor. These devices will alert your system if the ambient temperature reaches unusually high or low levels. The sensor must be programmed with the system.

Honeywell 5821 wireless temperature sensor and water sensor exte

A wireless temperature sensor is a peripheral sensor that alerts a panel when it detects temperatures outside of a certain threshold. This threshold can differ between different sensors, but it usually gives a pretty generous range. If your temperature sensor activates, then you know that the HVAC system in your home is definitely not working properly. Many temperature sensors are multi-purpose devices that also double as flood sensors or smoke detectors.

Please note that temperature sensors can be wireless or hardwired. If you plan on monitoring temperature wirelessly, this will require that your panel has a compatible wireless receiver. Most wireless Honeywell Panels come with a wireless receiver built-in, while hardwired Honeywell Panels will need to have one added separately. Most Honeywell Panels support the 345 MHz wireless frequency. The temperature sensors we will discuss here all communicate at this frequency.

One of the best wireless temperature sensors is the Honeywell 5821 Wireless Temperature Sensor and Water Sensor. This sensor has configurable DIP switches for setting the temperature thresholds. If you program as Loop 1 with both DIP switches Off, the sensor will fault when the temperature falls below 45°F for more than 10 minutes. You can also program the sensor as Loop 2 with both DIP switches Off to have the sensor fault when the temperature rises above 95°F for more than 10 minutes. If you plan to monitor both low temperature and high temperature thresholds, two separate 5821 transmitters will be required.

If you set DIP switch SW1 On and DIP switch SW2 Off and program as Loop 2, then you can have the sensor fault when the temperature rises above 75°F for more than 10 minutes. Finally, if you combine the Honeywell 5821 with a T280R Temperature Sensor Probe, then you can have the 5821 monitor a freezer or a refrigerator. This is can be very useful for preventing food spoilage in case the power goes out. Also keep in mind that the 5821 can be used as a flood sensor by adding a 470PB Water Probe. Again, one probe or the other can be used on a single sensor, but not both.

If you want to use the 5821 for freezer monitoring, after adding the T280R, you should set DIP switch SW1 to Off and DIP switch SW2 to On, and program as Loop 2. With freezer monitoring, the sensor will fault upon sensing a temperature above 10°F for more than 30 minutes. For refrigerator monitoring, you should set both DIP switches to On, and program as Loop 2. With refrigerator monitoring, the sensor will fault upon sensing a temperature above 30°F for 30 minutes. Because only one probe can be used with each 5821, to use both of these functions will require two separate transmitters and temperature probes.

Another option is the Honeywell 5800FLOOD, which doubles as a temperature sensor. With the appropriate programming settings the sensor can monitor for high and low temperatures. The high temperature threshold is 95°F, while the low temperature threshold is 45°F. The detected temperature must remain outside the threshold for 10 consecutive minutes for the sensor to activate. The sensor also includes a built-in probe for detecting water leaks.

If you only need to monitor for low temperatures and you also need a smoke detector, you might consider a Honeywell 5808W3 or a Honeywell 5800COMBO. These devices both include freeze detection functions that have the sensor activate at temperatures below 41°F. You will need to program multiple zones to get the full functionality out of the sensor. The Honeywell 5808W3 offers smoke, heat and freeze detection. The Honeywell 5800COMBO includes all these functions, plus the addition of carbon monoxide gas detection. Please note that though each of these sensors will detect a low temperature condition immediately, they will not transmit this signal to the alarm panel until the next RF check-in signal is sent. Low temp alerts are piggy-backed onto the RF supervision check-in signal.

Finally, there is one other way to wirelessly monitor your home's temperature using a Honeywell System. If you have a newer wireless all-in-one panel and a Z-Wave thermostat, then you can receive alerts from Total Connect 2.0. To do this, you must set a high/low temperature threshold and configure various settings from within Total Connect 2.0. You must then program two compatible temperature zones on the panel. One zone will be for high temperature, and the next zone in the sequence will be for low temperature.

In the LYNX Touch Systems, these are zones 180 thru 185. In a Lyric Controller, these are zones 280 thru 291. So if you are using a LYNX Touch, then you might use zone 180 for high temperature and zone 181 for low temperature on thermostat number 1. Then zones 182 and 183 would be for thermostat number 2, and zones 184 and 185 would be for a third thermostat. The same principle applies when using a Lyric. Make sure to save your changes when finished.

Note: These thermostat zones can report to a central station if enabled. In fact, they are enabled for reporting by default. If the Alarm Report remains set to "Yes" and Response Type is set to "24 Hour Auxiliary", the zone may be interpreted as a medical alert when received by the central station. If you do not properly define these zones with them, a false dispatch could occur. If you choose to use these zones, be sure to properly define them with the monitoring station before putting them into service. Discuss any dispatch or notification requirements with the monitoring station at that time.

Below is an example of what temperature zone programming looks like on a Honeywell L5210:

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