Look at them very closely thru a magnifying lens. Be sure they are not termites. You can find comparison pictures on the Internet.

Do it yourself treatment to put around the perimeter of the house is available at many big box stores like Home Depot or Lowes.

Ants are coming in by the dozens to die in my house. They just pile up near the door. What is up? How can I stop it? They are also near an air vent connected to my central heating system. Thanks.