There are several possible reasons why your house may feel cold at 73 degrees Fahrenheit:

1. Insufficient insulation: If your home is not properly insulated, it may feel colder than the actual temperature. Insufficient insulation can allow heat to escape, making your home feel colder.
2. Drafts: If your home has drafts, it can make it feel colder than the actual temperature. Drafts can occur around windows, doors, and other openings, allowing cold air to enter the home.
3. Humidity: Low humidity can make a room feel colder than it actually is. Dry air can cause the moisture in your skin to evaporate more quickly, making you feel cooler.
4. Personal preference: Some people may simply have a lower tolerance for cold temperatures and may feel colder at 73 degrees than others.

If your home feels cold at 73 degrees, there are several steps you can take to make it feel warmer:

1. Increase insulation: Adding more insulation to your home can help keep it warm and reduce heat loss.
2. Seal drafts: Finding and sealing drafts around windows, doors, and other openings can help keep your home warm.
3. Use a humidifier: Increasing the humidity in your home can make it feel warmer.
4. Wear warm clothing: Wearing warm clothing can help you feel warmer in a cool house.
5. Use a space heater: Using a space heater can help increase the temperature in a specific room or area of the house.

If these steps do not help, it may be a good idea to have a professional assess your home’s heating system to ensure it is functioning properly.