Thermostat not heating to desired temperature

[Lada]

Second day in a row our Nest Thermostat says it’s heating, but doesn’t get to the temperature we set. It’s set on +22, but doesn’t go above +19 or + 20. On the display it says 50 minutes to 22 or one hour to 22, but doesn’t get there. Fan is blowing a cool air from the vents. And in the history it says it was heating for 21 hours yesterday when in fact it wasn’t. 
we changed furnace filter yesterday, also reset thermostat and turned furnace off and on, but that didn’t help. At night temperature went down to +17. 

[Jake]

Hey Lada,

I wanted to follow up and see if I could be of any help. I found an article that has some troubleshooting steps. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further. 

Best regards,
Jake

[Jake]

Hi Lada,

I wanted to check in and see if you are still in need of any help. Please let me know, as I would be happy to assist, and answer any questions you may have.

Best regards,
Jake

[Jake]

Hey there,

I wanted to check in with you, and let you know that I will be locking the thread in 24 hours.

Best regards,

Jake