Your house can feel cold at 73 F due to low humidity, poor insulation, poor heating, leaky windows, drafty windows etc.
When it's winter and your house is 73 F or above and you're still feeling cold it is likely that your house has either leaky windows, improperly sized furnace or poor insulation in your walls, attic etc.
Low humidity in the home can also lead to the house feeling colder and when it's windy out wind can also seep through the windows and cracks around your home allowing cold air into the home making it feel colder.
If your furnace is not working properly or is not properly sized the furnace won't be able to keep up and keep the house warm like it should be.
So the furnace would have to run more to keep the home warm.
Also using a humidifier in your home can increase the temperature because moist and humid air is warmer than dry air.
You can also have a whole house humidifier installed which adds humidity to the air while your furnace is running.
Also consider looking for gaps and air leaks around doors, windows, pipes etc and seal all those places up to prevent heat escaping and prevent cold air from coming into your home.
Get professional air sealing for your home and attic to seal up air leaks that are causing heat escape.
Upgrade your existing home and attic insulation to help create a solid thermal barrier to keep heat inside.
Check and repair ductwork if needed.