Premier Inn at Heathrow Terminal 5

from the hotel website - on the main page:

Less than two miles from Terminal 5, with easy bus links to other terminals

and after driving directions there is :

Transport and local information:

This hotel is in London zone 6. Closest underground station is

Heathrow T5

Heathrow Terminal 5 - 3.5 miles

Heathrow Terminals 1, 2, 3 - 3 miles

Heathrow Terminal 4 - 5 miles

Heathrow Terminal 5 Station - 1 mile

Bus service 423 runs every 15 minutes to and from Terminal 5 (Stand 6
at T5).

Does that help?

We used one of the local mini-cabs when we stayed there earlier this year. The door to door service from the hotel to the terminal was great, and the cost was around 15 pounds as I recall.
The hotel will book the taxi for you upon request.

Perfect, thanks all!

It's probably just as easy to stay at the PI T4 and then use the inter terminal transfers to go to T5. The T4 hotel has a reputation for pretty keen pricing.

I also would stay at Premier Inn terminal 4 and take free transport between terminals over Premier Inn terminal 5 and a taxi.

I’m also considering this (but using bus). The T4 PI looks nicer on the website. Is it really 20 mins on bus from PI T4 to T5? Probably depending on time of day. A July Saturday morning around 8:30?

It probably does take 20 minutes by bus because of the relationship spatially of T4 to T5, the layout of the landside roads, and you probably have to change at the Central Bus Station- T2/3.
Rail is just the more logical way to make the transfer, other than in the small hours of the night when there is the special inter-terminal bus runs (from 0100 to 0500).

The H30 bus runs from Termianl 4 to Terminal 5 approximately every 20 minutes. It's free between the terminals. No changes.

https://www.diamondbuses.com/bus-services/se/seh30/

However, you are better off taking a rail option of either the Underground, the Heathrow Express or the Elizabeth Line.

You take either train one stop to Heathrow Terminal 2/3 and then transfer to another train one stop to Terminal 5.

If taking the Underground you need to use either an Oyster Card or contactless payment but you won't actually be charged. For the Heathrow EXpress or Elizabeth Line you get a free transfer ticket.

The underground runs the most frequent service every few minutes. But since it's a Saturday, you have to be aware of any engineering works on either of the lines that may limit service.

And don't forget the walk from the Premier Inn at Terminal 4 to the actual terminal takes 7-10 minutes depending on how fast you walk.

The H30 bus is the one I alluded to as running in the small hours. It does not run in the daytime as stated in the previous reply.

In any event if you look at the timetable it is being withdrawn after close of service on 31 December 2023, with no replacement.

Having looked into the matter more carefully the red London buses which connect the two terminals without a change are the 482 and the 490. Each is timed to take 13 minutes. The 482 runs half hourly, the 490 runs every 20 minutes, both from stop 11 at Terminal 4. Both will show Terminal 5 as their destination.

You don't have to go back to T4 to catch them as both observe a stop before T4 a few yards along the Southern Perimeter Way, just past the PI, after it's junction with Sheffield Road.

EDITED TO ADD TIMETABLES-
BUS 482 Timetable- http://londonbusroutes.net/times/482.htm;
BUS 490 Timetable- http://londonbusroutes.net/times/490.htm

By the way the London buses above are not free (cost is £1.75 as on all London buses), and the Heathrow Free Travel Zone map which says that the H30 runs all day inter terminal has been out of date for quite a few months now.

We've stayed at the Premier Inn near T4 several times and used the underground train to connect with T5. It worked out fine, though it's a bit of a hike to get to the hotel.
We've since switched our allegiance to the PI near T5 - just personal preference driven by the fact that we don't mind paying the minimal cost for door-to-door service using one of the local mini-cabs, and the one near T5 is a short walk to the village of Harmondsworth where there are a couple of atmospheric pubs for a pint or dinner. Plus, we just like to stretch our legs and the walk there is a pleasant one. Nearby is Harmondsworth Moor if you fancy a longer walk in a natural setting.
We've generally found the quality of the rooms and the amenities to be about the same at all of the Premier Inns we've used.
Might mention that if you don't mind a bit of a splurge the Sofitel Hotel at T5 is the nicest and most conveniently located of the bunch.

Note that PI T5 is also close to multiple other hotels along the Bath Road corridor, so
you have choices.

The Thistle T5 is reached via robotic electronic pods from T5.

Taking the Tube to a nearby off-airport station such as Hatton Cross would provide
some other options.

Here is the bus diagram for Heathrow, showing the routes as well as the major hotels
served by buses:

Heathrow buses

Thanks to all for chiming in with additional info about the transit, and other suggestions. We will probably stick with T5 PI since it’s a shorter commute on Saturday 8:30 am, and we’ll probably arrive early enough from Bath on Friday to appreciate a little extra outdoor time before the long flight back to CA.

Edited to update: The Sofitel seems like a splurge at nearly £217, but we booked a room there after all. We’ll take free tube + walk to Green Man pub for (vegan) dinner. A very comfy way to end a trip. Great you tube videos of the walk to T5!

Bertino, will you please report back after your trip? Safe travels!

We decided to stay at the Sofitel at T5. Just wanted to take the path of least resistance.

We decided to stay at the Sofitel at T5. Just wanted to take the path of least resistance.

You're going to love it. It's a really nice hotel. And just a few minutes walk--indoors--to Terminal 5.

I've stayed numerous times.