I recently needed to stay at a Heathrow airport hotel in order to make an early flight. A big annoyance of doing this is the difficulty of getting from a hotel to the airport. There are plenty of hotels that are just half a mile from the terminal 1-3 centre, but to get to them you have to use the Heathrow Hoppa bus service. This isn't a bad service, but is apallingly expensive: 4 UK pounds, each way, for a journey of half a mile. A half-mile is an easy walk, so I really balk at using a bus, let alone one that charges such a ridiculous fee. Fortunately there's an alternative, although Heathrow makes it hard to find.
The main Heathrow terminals are connected to the outside world through a tunnel, and there is no pedestrian access through this tunnel. Fortunately it seems that as part of the deal to use a former pedestrian tunnel for another purpose, Heathrow has to provide a free bus service through the tunnel. As a result there is a zone of free buses that extends just outside the airport, stopping right outside a number of the airport hotels. Providing you are within this zone, your bus journey is free. And not just that, it seems that the buses are more frequent than the Hoppa.
It's not easy to discover where to find these buses and the details about the zone. I had to go to the bus stops in Heathrow and look for the local buses, there I found a map that showed me were the free zone is. When I talked to the hotel I was staying in, initially they only mentioned the Hoppa, but once I pressed them, they did start talking about the free service.
Tricky it may be to get the information, but it's well worth it to use a service that's cheaper and better than an annoying gouge.