Taxi from Heathrow Airport to hotel

Charlotte, where is this hotel? Is it in central London?

A taxi is not the default choice for travelling from Heathrow to central London. It is the most expensive and not the fastest.
Most people, unless they have so much luggage they can't handle it, use public transport.

• The cheapest is the tube (Underground), which from Heathrow to central London costs £5.10 Monday to Friday from 0630 to 0930, £3.10 at other times. Takes approx 1 hour to central London
• Next, slightly faster but more expensive is the Heathrow Express non-stop to Paddington Station.
• Next is a "mini cab", that is a pre-booked taxi. The firms Emma lists are mini-cab firms.
• Most expensive is a taxi from the taxi rank. This will cost £45-£70 and will not necessarily be any faster than public transport. In the rush hour it will be a lot slower.

See here (official Heathrow website): http://www.heathrow.com/transport-and-directions/getting-to-central-london

Charlotte, in addition to Chris' good information (yes, taxis are very expensive in London), did you do the homework on using your phone abroad? Do you know if yours will even work overseas, and the cost of making calls on your current plan if it does?

See if your hotel offers transport service from the airport to the hotel. It may be less expensive than a cab and a driver will (should) be waiting when you exit customs.

Hotels offering their own transport is not very common in Europe. I would say it is restricted to some airport hotels, and 5-star hotels.

All licensed taxis will be the same. They are running a controlled meter or charging by zones. It will be same for all.

Chris F, I agree, it's not very common in Europe, but popular in S. America and is through a third party vendor, not a hotel owned shuttle like in the U.S.