Article Summary:
The Nest Learning Thermostat will sometimes delay or prolong heating and cooling for a few minutes. This prevents damage to your equipment.

When heating and cooling systems are turned on and off again within a short amount of time, it can damage the equipment. The Nest Learning Thermostat implements a delay between on and off states in order to protect your system. This delay is called the minimum on-off time.

To protect the heating and cooling systems it controls, the Nest Thermostat's minimum on-off times are five minutes for heat pumps and air conditioning systems and three minutes for conventional heating systems (like furnaces and boilers). The Nest Learning Thermostat uses these minimum on-off times for all temperature changes in its schedule.

For example, if the Nest Thermostat cools to a target temperature of 76ºF/24ºC and turns off, it will wait five minutes before turning cooling on again. Even if the temperature increases to 78ºF/26ºC , the Nest Thermostat won’t turn on the AC until five minutes have passed. Alternately, if the AC has been on for just two minutes and reaches the target temperature, the Nest Thermostat will keep it on for three more minutes to observe the five minute minimum on time.

These limits apply only to temperature setpoints that are in the Nest Thermostat's schedule. If you make an immediate temperature change on the Nest Thermostat or Nest Account, the Nest Thermostat won’t use any minimum on-off times for conventional heating systems. However, the Nest Thermostat will still use a two and a half minute minimum off time for air conditioning and heat pump systems. So, if you try to turn on an air conditioning or heat pump system just a few minutes after it has turned off, you’ll have to wait two and a half minutes before it turns on again. If this occurs, the Nest Learning Thermostat will display a two and a half minute countdown below the target temperature. When the countdown display reaches zero, heating or cooling will begin.

Note: Forced air heating and cooling systems often keep the fan on for a few minutes after they have been turned off, in order to flush the remaining warm or cool air out of the ducts. This is normal and not a result of minimum on-off times.