You are absolutely correct! The advantage of a hybrid depends largely on three things: 1) the ICE is fully warmed-up; 2) the traction battery is warmed up; and, 3) the trip length is sufficiently long to take advantage of 1) and 2). My 2021 450h is parked in our driveway. On cold, winter days, short trips yield very poor mileage. However, yesterday temperatures were pleasantly in the high 50s and low 60s. My 30 mile R/T yielded very nice MPG results.

 

The winter fuel blends always cause mileage to go down on all vehicles. The additives are less energy efficient in the winter than in the summer.

 

I’m typically getting between 24 to 26 mpg. If I tow a small trailer on the highway, it drops down to 20 mpg.

 

Ive only checked my 22 twice and once was 30.5 and second time was 27.6..

 

2020 RX450h fill up at 10,660 miles 03/24/23. Traveled 404.1 miles, 100% city short trips mostly 14 miles each way, 0% highway, weather mostly 40F to 80F.
32.1 mpg calculated. The RX said 29.1 mpg. Filled up with OT Premium 93 Octane. No so sure I believe the 32.1. I fill on the slowest fill speed, first notch, and after it clicks off, I squeeze the handle again until it clicks off, usually a second or so. The fuel gauge is where is usually is when full.

 

2020 RX450h fill up at 11,087 miles 05/07/23. Traveled 426.9 miles, 100% city short trips mostly 14 miles each way, 0% highway, weather mostly 60F to 80F.
29.7 mpg calculated. The RX said 31.2 mpg. Filled up with Sam's Club Premium 93 Octane.

 

Since we bought our '22 RX450h last November, I observed 26-26.5mpg during cold/winter driving and now 28-29 mpg during warmer temps. Hopefully it stays at these numbers, because that would exactly match the fuel economy we had on NX300h, which we traded in for this RX.

 

2020 RX450h fill up at 11,516 miles 06/12/23. Traveled 429.2 miles, 100% city short trips mostly 14 miles each way, 0% highway, weather mostly 60F to 85F.
31.5 mpg calculated. The RX said 31.6 mpg. Filled up with Sam's Club Premium 93 Octane
.

 

On a trip to Palm Desert last week, I noticed that the fuel mileage on my wife’s Lexus was only getting 16mpg! With this being a hybrid, and all highway driving at 70mph, this is ridiculous! What could be causing this to be this bad???

 

Was this calculated or from the RX's display? I just came back from a trip and will be calculating and posting my MPG results asap. From my experience 70 plus mph produces 26 to 28 mpg. The RX does best below 70 mph. 16 mpg is way too low.

 

Was there wind? Was there a lot of idling? Rooftop carrier? Typically, that’s pretty low, but factors such as I asked about above, can affect the RX 450h mpg significantly. My mpg goes way down when temperatures get to 100° or higher, due to A/C being used at the max. I’ve only seen mine that low, when I tow a trailer.

 

My MPG records from a recent Trip.

2020 RX450h fill up at 11,961 miles 07/15/23. Traveled 445.3 miles, 50% city short trips mostly 14 miles each way, 50% highway, speeds up to 74 mph, weather mostly 85F to 90F.
33.6 mpg calculated. The RX said 31.5 mpg. Filled up with Sam's Club Premium 93 Octane.

2020 RX450h fill up at 12,248 miles 07/15/23. Traveled 287.4 miles, 0% city, 100% highway, speeds up to 74 mph, weather mostly 85F to 90F.
32.0 mpg calculated. The RX said 30.1 mpg. Filled up with Sam's Club Premium 93 Octane.

2020 RX450h fill up at 12,446 miles 07/22/23. Traveled 198.0 miles, 50% city short trips mostly 5 miles each way which ate up fuel, 50% highway, speeds up to 74 mph, weather mostly 85F to 90F.
26.9 mpg calculated. The RX said 26.9 mpg. Filled up with Sam's Club Premium 93 Octane.

2020 RX450h fill up at 12,726 miles 07/22/23. Traveled 280.1 miles, 0% city, 100% highway, speeds up to 74 mph, weather mostly 85F to 90F.
31.7 mpg calculated. The RX said 30.5 mpg. Filled up with Sam's Club Premium 93 Octane

 

2020 RX450h fill up at 13,108 miles 08/07/23. Traveled 381.9 miles, 50% city short trips mostly 14 miles each way, 50% highway, weather mostly 80F to 95F.
29.4 mpg calculated. The RX said 30.2 mpg. Filled up with Sam's Club Premium 93 Octane

 

Sadly, I gave up on Lexus. My 2016 RX 450h NEVER got the advertised mpg & began having serious electrical problems. I live almost 200 miles from the closest Lexus dealer & the local Toyota dealer couldn’t get the electrical issues fixed, so we traded for a 2023 Ford F-150 Platinum Powerboost hybrid. I can’t stand any of the new Lexus styling, so we are dealing with just a local Ford dealer. It was a tough decision, but I think we made the right choice. I wish everyone continued good luck & good mileage with their Lexus!

 

Regarding mileage our 450h averages about 28.5mpg. On rare occasions we’ve obtained 31mpg and the lower end has been 25mpg. California premium octane is only 91, so that likely had something to do with the lower numbers. Mileage was all calculated via a mobile app as the Lexus readouts are not that accurate.

You and I started this forum around the same time, so I’ve followed your situations. Our Lexus sat unused for almost a year because of a recurring issue that caused my wife to lose confidence with the RX. That left me starting and driving it occasionally to keep the batteries from dying. We have relegated this vehicle to a run about replacing an older vehicle that we literally ran into the ground for years. Our quandary with Lexus, even though we reside in Southern California and have several dealerships to choose from, is that each and every time the vehicle is taken into Lexus for service, it comes back with a scratch, ding or something undone (this from two separate Lexus dealerships). Lexus does fix matters, but it is additional time spent that is better spent elsewhere for both parties. This was our first Lexus, but we are now considering the Mercedes-Benz EV lineup as there are two major dealerships close by and although Lexus is known for its reliability, we didn’t encounter that in our first few years of Lexus ownership. Dealing with Lexus Corporate was a mixed bag of both utter disdain to some extremely competent engineers; Lexus’ first-tier of customer service interface is utterly abysmal…at least it was for us.

Good luck with your new vehicle and I hope it provides you with the balance you sought in vehicle ownership. Stay healthy and enjoy life!