If a solid fuel burner has a nominal heat output of 5kw or below you do not require an air vent. If the stove has a nominal heat output superior to 5kw you must have a vent that cannot be closed. The vent must be within the same room as the stove and go to an outside wall. There are sadly people who advise that you can always open a window. If you come across this sort of service you could save yourselves a lot of time and money and show the person to the nearest door.