Sanity check

[Brechin Slate]

Just refuelled and put the figures into Fuelly.  I'm getting just over 38 mpg which I have to say I find disappointing but wonder if my expectations are too high.  Looking for a sanity check from members as I keep seeing reported figures of high 40's and 50+ mpg.

Some facts:

2017 IS300h Premier on standard 18" wheels, factory fitted Bridgestone tyres at 36 psi

Tesco petrol 95 Octane

No error codes on dash or Carista

Mostly short journeys of less than 5 miles in cold weather with A/C (heating) and lights (I know this is a big factor but I wouldn't have thought >5 mpg)

A couple of longer motorway journeys, 50 miles each way

Car serviced and last hybrid check passed

Should I be expecting more?  My IS250 was giving me 33 mpg in similar circumstances.

If anyone replies saying they get 50 mpg in similar conditions I'm off to the Tesla dealer..

[wharfhouse]

Cold weather and short journeys don't do the fuel consumption any good as the engine has to work to heat the car and there is quite a drain on the Battery for lights wipers etc. Consumption will improve a lot on longer journeys and especially in warmer weather (best mpg seems to be when air temp around 20C). Overall across a few years of mixed driving I'm around 48mpg on the car computer (17" wheels) - wait for it to average over some warm weather and longer runs to get a better idea. 

[ColinBarber]

Cold weather and short journeys definitely aren't going to help your mpg.

I set one of my display options to show mpg after start so you can see the mpg per journey - that will quickly show you how uneconomically those short journeys can be.

The hybrid system on the IS is quite slow to shut down the petrol engine once it has started. If I did a short journey to the station and back, only around 3 miles round trip, I'd struggle to get more than 30 mpg, even when it wasn't winter. My wife's Prius, with the next gen hybrid system, would shut down much sooner and you could get 45 to 55 mpg on the same journey.

On longer runs, typically 15 miles, my IS300h used to average around 48 mpg - that was an F Sport with a mix urban/dual carriage way/motorway. The Premier should be similar, if slightly better due to better aerodynamics, but it is normally the vehicle on 17" wheel that consistently get over 50 mpg.

[Thackeray]

33 minutes ago, Brechin Slate said:

I'm getting just over 38 mpg which I have to say I find disappointing but wonder if my expectations are too high.

For short journeys in winter, 38 mpg doesn't look bad. If you switch to the energy consumption screen (press something like Menu/ Car / Trip Information you'll see something like this:

 

If you watch this screen when you start from cold in the snow with the heater on, the heated seats, heated rear screen, wipers plus maybe lights and some other things, you'll see that you're getting about 20 mpg in each of the first five minutes  while the car warms up. Each minute of the journey is represented by one bar of the graph. If you end the journey before the car has fully warmed up, you'll get low mpg. But after, say, 10 minutes when the engine has reached its normal operating temperature mpg will improve, even in winter.  And it warms up quickly in the summer and mpg improves even for short journeys, so over the year it all balances it out.

[royoftherovers]

1 hour ago, Brechin Slate said:

Just refuelled and put the figures into Fuelly.  I'm getting just over 38 mpg which I have to say I find disappointing but wonder if my expectations are too high.  Looking for a sanity check from members as I keep seeing reported figures of high 40's and 50+ mpg.

Some facts:

2017 IS300h Premier on standard 18" wheels, factory fitted Bridgestone tyres at 36 psi

Tesco petrol 95 Octane

No error codes on dash or Carista

Mostly short journeys of less than 5 miles in cold weather with A/C (heating) and lights (I know this is a big factor but I wouldn't have thought >5 mpg)

A couple of longer motorway journeys, 50 miles each way

Car serviced and last hybrid check passed

Should I be expecting more?  My IS250 was giving me 33 mpg in similar circumstances.

If anyone replies saying they get 50 mpg in similar conditions I'm off to the Tesla dealer..

38mpg is fine Mike. Stop being impressed by others.

[Mr Vlad]

As Roy said. My is300h averaged high 30's. My journeys were short like yours. On a run to Leeds tho I'd be getting 50 easily. 

Don't sweat about your mpg figures. There's nowt wrong with them. Oh you were getting better mpg in your is250 than I'm getting on the short journeys in mine.

[Brechin Slate]

Thanks all, sound advice as always, I'll find something else to worry about 😊

[royoftherovers]

2 hours ago, Brechin Slate said:

Thanks all, sound advice as always, I'll find something else to worry about 😊

Don`t you dare Michael !

[Guest]

I have covered about 17000 miles now in my 2017 Advance and average about 50mpg, I have never checked how accurate the computer is and I do quite a few 50 mile plus journeys 

[paulrnx]

I think I only ever averaged between 40 and 44 mpg over a tankful. For both IS300 cars that I’ve owned. Sure there were journeys where I averaged well over 50 in both cars in favourable conditions but never over a full tank and across multiple journeys.

[200h]

one thing that doesnt help your fuel economy

are hills and in Hampshire you seem to have your

far share of high points

https://en.wikipedia.org/wiki/List_of_hills_of_Hampshire

 i'm not saying they all have roads on them but it does give

a good indication of how the land sits

[Brechin Slate]

On 2/8/2021 at 5:33 PM, Thackeray said:

For short journeys in winter, 38 mpg doesn't look bad. If you switch to the energy consumption screen (press something like Menu/ Car / Trip Information you'll see something like this:

 

If you watch this screen when you start from cold in the snow with the heater on, the heated seats, heated rear screen, wipers plus maybe lights and some other things, you'll see that you're getting about 20 mpg in each of the first five minutes  while the car warms up. Each minute of the journey is represented by one bar of the graph. If you end the journey before the car has fully warmed up, you'll get low mpg. But after, say, 10 minutes when the engine has reached its normal operating temperature mpg will improve, even in winter.  And it warms up quickly in the summer and mpg improves even for short journeys, so over the year it all balances it out.

Great tip, tried this yesterday and will try it on a longer run tomorrow 

[ColinBarber]

7 minutes ago, Brechin Slate said:

Great tip, tried this yesterday and will try it on a longer run tomorrow 

It's very difficult to know what the average is though over a period of time with the bar chart. I always use the After Start measurement for one of the display options - you can then just flick to it if you are interested after a particular journey. Then always subtract 1 or 2 mpg as the fuel computer is alway optimistic.

 

[Stuart Aspey]

Starting year 4 with my 13 plate Lexus Is300h Premier on 18' wheels. Yes, I struggle to get an average at 40 or higher. The entry level with smaller thinner wheels gets better MPG, but nowhere near the suggested figures. (but, it's 10mpg better than my first gen IS and only £10 a year emission tax, so I'm keeping quiet about fuel economy) 

[Stuart Aspey]

On 09/02/2021 at 7:35 AM, Derant said:

I have covered about 17000 miles now in my 2017 Advance and average about 50mpg, I have never checked how accurate the computer is and I do quite a few 50 mile plus journeys 

Yes, longer journeys really seem to like these cars when it comes to fuel economy. Short journeys and hills remind you that this is a big engined heavy car. 

[Brechin Slate]

44 minutes ago, Stuart Aspey said:

only £10 a year emission tax,

Missed out on that and am paying the Premier premium for the high list price. At less than a quid a day I convinced myself the instant I saw the car that it's worth it for a few years and I'd rake the money back by driving economically.  Well, that was the theory.. 🙂

[royoftherovers]

3 minutes ago, Brechin Slate said:

Missed out on that and am paying the Premier premium for the high list price. At less than a quid a day I convinced myself the instant I saw the car that it's worth it for a few years and I'd rake the money back by driving economically.  Well, that was the theory.. 🙂

The view of the sensible man who does what he wants, rather than following the crowd.

[Stuart Aspey]

Ah, the plus side of buying a second hand (and older) Is..   You'll make the money back in fuel efficiency over other petrol cars and in reliability part wear. 

[royoftherovers]

1 hour ago, Stuart Aspey said:

Ah, the plus side of buying a second hand (and older) Is..   You'll make the money back in fuel efficiency over other petrol cars and in reliability part wear. 

And what about the cost of a satisfied mind Stuart ?

[Stuart Aspey]

1 hour ago, royoftherovers said:

And what about the cost of a satisfied mind Stuart ?

Very well said. Yes, Lexus are always set to excel themselves in customer services and reliability. 

[route66]

This is my story - MPG Stats from my 3 years of IS300H use:

• Average over 3 years: 39.39 MPG (Calculated)
• Difference between Summer and Winter driving: Approx 10 MPG
• Best/Worst calculated tank to tank figure: 47.85/31.82 MPG
• Best trip MPG: 62.7 MPG (Gentle 50 mile Motorway trip in summer - under or @ 100 KMPH limit)
• Best long trip: 50.8 MPG (125 mile Motorway trip in summer - driven mostly @ 120 KMPH limit):

[Brechin Slate]

1 hour lap of the New Forest.  Much better!

[mtDrews]

Just want to add an anecdote here...

This is my first winter with the 300h here in northern Sweden, and I've managed to get an impressive average 52.3 UK MPG in colder than -20 degrees C fill-up to fill-up.  I was really surprised with this, but you have to consider that the road condition at the time didn't even allow you to go the speed limit most of the time. Which leads to very slow and controlled acceleration and deacceleration and a maximum of 50 MPH. Also this particular trip had virtually no stop-start driving, it was basically just coasting between 30 - 50 mph.

I should also add that the SE 300h has wider rear summer tyres so that of course favours winter mpg and obviously the AC can be always off in the winter as well.

[Thackeray]

45 minutes ago, mtDrews said:

I've managed to get an impressive average 52.3 UK MPG in colder than -20 degrees C fill-up to fill-up

Where is the car parked overnight? Is it outside at -20C or is it in a nice comfortable garage at +10C? If the car doesn't have to go through a long warmup stage fuel consumption will be much better.

In Canada, they used to have plug in heaters for the radiator to prevent freezing. Don't know if this is still the case. When you went to the supermarket there were sockets outside to plug in the heaters. And it also used to be that trucks would be kept running 24 hours a day as otherwise they wouldn't start until spring came.

[200h]

Andre said "This is my first winter with the 300h here in northern Sweden"