This smell shouldn't ignored. Even though you don't see any Antifreeze on your carpet, it could just be a really small pin hole leak that lets out a little antifreeze when you start the car and then when you're driving it may be rushing through the core too fast to leak out that hole.
Depending on how old the car is your heater core might need replacing.
Or you could also have a tiny leak a hose under the hood where you can't see it.
It's possible for smells to come from under the hood into the car.
If you can't find the leak yourself, I'd recommend taking it to a local Mechanic who can run a pressure test on it.
This small problem could lead to bigger problems in the future.