Originally Posted by
JIMCHI
It looks like the cheapest and most efficient way is to take Heathrow Express to Paddington and connect to the Circle Line to Victoria.
Cheapest ? definitely not. Taking the tube and changing at South Kensington is much cheaper than the HEX/tube combo.
Most efficent ? debatable. The tfl website shows the HEX/tube route ifrom Heathrow Central) is 42 minutes, and the tube route 49 minutes. As HEX runs every 15 minutes, you'll need to time your arrival at the HEX station just before the train departs, otherwise the tube is quicker. Also, Circle line trains are less frequent than the Picadilly line, so there's a good chance of a few minutes extra wait at Paddington.
and, FWIW, the HEX-southbound Circle line transfer at Paddington is through narrow passageways which get uncomfortably crowded at peak times. I would take the tube.