Furnace Not  Turning On ? Here 5 reason.

1. Thermostat Issue

Make  sure your thermostat is set to heat 

2. Issue with Natural Gas Line

First and foremost, verify that the gas is turned on. 

3. Furnace Problem

Your furnace could also be the cause of the problem. Furnace replacement its one of your options.

4. Something wrong with Air Flow

Is your furnace working in some parts of your home and not in others?

5. Replace Air Filters

make sure air filters up to date