Originally Posted by corporate-wage-slave

The Aerotel is inside the airport buildings of T3, close to arrivals. I've never used it, but it is physically convenient. You would take the transfer bus service from T5 to T3, then use the UK Border to exit rather than Flight Connections. Alternatively go landside at T5 and take the HEX to T3. The service frequency is at best 6 an hour, whereas the buses are 28 an hour. For HGI - there are actually 2 of them. The one at T2 is slightly over from T2, and a 5 - 10 minute easy walk from T3. I would in that circumstance to landside at T5 and use the tube, Piccadilly line, to T2, just because it's the better laid out and there are signs. See the Hilton board for photos of the access to the HGI.

The other HGI is at Hatton Cross, it's usually half the price of T2, but it's not half the quality. In that case you take the tube from T5 to Hatton Cross and a 8 minute walk from there to the HGI. Then that route back from the hotel to your T3 departure. You can allow 20 minutes for that from hotel to T3 security, it may take less than that, whereas it's under 10 minutes for HGI T2 to T3.