Are muggles able to use the Floo network?

Question

Are muggles able to use the Floo network (alone or alongside a wizard)? If they can't do that, what happens when they try?

Answer 1

• Well, at least one Muggle can:

  Stephen Fry: Oh dear me. Hello! Hello there! Hello, am I in the right place? It’s a long time since I’ve used Floo powder and I sometimes end up in the wrong place. Is this the Royal Albert Hall? (Fry, Stephen, interviewer: J.K. Rowling at the Royal Albert Hall, 26 June 2003.)

  JKR can too:

  Lizo: How do you communicate, how does all that work, and how often? {{ discussing talking to Steve Kloves working on CoS film }}
  JKR: Uh, it... it varies to what we're doing at the time.
  Steve: Owls.
  JKR: Owls, mainly, obviously, a bit of Floo Powder. [laughs]
  (Mzimba, Lizo, moderator. Chamber of Secrets DVD interview with Steve Kloves and J.K. Rowling, February 2003.)

• More canonically, it seems Muggles likely CAN use Floo network/powder, though evidence is circumstantial at best:

  Nearly every witch or wizard home is connected to the Floo Network. While a fireplace may be disconnected by the use of a simple spell, connection requires the permission of the Ministry of Magic, which regulates the Floo service and prevents Muggle fireplaces becoming inadvertently joined up (although temporary connection can be arranged in emergencies). ("The Floo Network" article on Pottermore)

  Now, the bolded text can have one of two explanations. If a Muggle fireplace connects by accident to the network, one of 2 bad things can happen

  1. A witch or a wizard accidentally exits at a Muggle place.

     This is extremely unlikely, as you need to deliberately name your destination when Floo traveling, and accidental Muggle house wouldn't be named

  2. Or, much more likely, a Muggle would accidentally stumble into the fireplace and travel somewhere magical (violating International Statute of Secrecy).

• Also, we know from Pottermore that Floo can be used for:

  Thirdly, it can be used to transport children, the elderly and the infirm.

  This seems to imply that there's no magic excercise needed to use it (children can use it); which makes it possible that a Muggle could use it as well.

• Also, we know that similar long-distance transport CAN be used by Muggles: Portkeys.

  Accidents have occurred, however; two Muggle dog-walkers found themselves accidentally transported to a Celestina Warbeck concert in 2003 (Pottermore)

Please note that there is no direct evidence for either yes or no answer - not in books, not on Pottermore, not in any JKR interview to date.

Answer 2

We have no evidence of a Muggle using Floo powder. BUT we know that Muggle fireplaces can be hooked up to the Floo network.

"I had your fireplace connected to the Floo network, you see--just for an afternoon, you know, so we could get Harry. Muggle fireplaces aren't supposed to be connected, strictly speaking--but I've got a useful contact at the Floo Regulation Panel and he fixed it for me."

(Mr. Weasly in GoF chapter 4)

Since all you have to do is drop powder and say something--it requires no magic or anything--they are almost definitely able to use Floo powder. However, this is not certain.