Fan off delay time

[LS-HVAC]

I am a HVAC technician, I would like to know if there is a way to activate a fan off delay on the nest thermostat to use the energy left over equipment coils in order to get the 100%  efficiency of the system. 
Also it a good option to protect the systems from overheating in the case of an old furnace that doesn’t comes with an internal delay in the board?

[Lance_L]

Hello LS-HVAC,

Thanks for reaching out to the Google Nest Community. I’d be happy to help you with your questions.

Nest thermostats have a feature called Airwave. This turns the compressor off a little before reaching the target temperature. Then it runs the fan alone until it reaches the temperature you want. Airwave will only work on Google Nest thermostats that control central air conditioning.

You can check out this guide to learn about Airwave and how to change settings.

I hope that helps.

Best,

Lance