MPG for those interested

[Jazzik]

Looking at fuel consumption over a single trip or a single tank of fuel is a rather pointless exercise. It doesn't bother me that, on one occasion during the winter of 2023/2024, the fuel consumption over a single tank was as high as 6.16 l/100km (45.9 mpg).
Ultimately, the AVERAGE fuel consumption (the only thing of interest) of our Jazz, measured over more than four years and 34,500 km (21,450 mi), is 4.62 l/100km (61.1 mpg).
We track fuel consumption on Spritmonitor: https://www.spritmonitor.de/en/detail/1280885.html

[Downsizer]

Whatever MPG my jazz returns its still a step above my similar sized 1.4 nissan note delivered and no doubt what mk 3 jazz owners achieved too ?

Yes, over 70,000 miles in 9 years my Mk3 delivered a true 51mpg. The first year of my Mk4 has achieved 59 mpg. The mix of driving has changed a bit, with more    very short trips.

[coldstart]

...
(the only thing of interest) of our Jazz, measured over more than four years and 34,500 km (21,450 mi), is 4.62 l/100km (61.1 mpg).
We track fuel consumption on Spritmonitor: https://www.spritmonitor.de/en/detail/1280885.html

I completely agree with you: Only true volume filled up versus distance covered overall is truly signifcant.

However, I do hope you're keeping an offline record of your car's consumption as well as spritmonitor.de currently seems to be "unavailable":  503 Service Temporarily Unavailable
(what if they got hacked, neglected backups and all data were lost?)

As you can tell by my signature I'm keeping record on spritmonitor.de as well but not only!
I still have my trusty oldfashioned local spreadsheet as well (I know "double work" - hey! I'm retired, I've got all the time in the world)

[Downsizer]

Spreadsheet? What’s wrong with a notebook and a pencil under the centre armrest? Mine goes back many years!

[coldstart]

Spreadsheet? What’s wrong with a notebook and a pencil under the centre armrest? Mine goes back many years!

absolutely nothing!   (paper can't be hacked!)

btw: spritmonitor.de seems to be still offline ... (so my spreadsheet data just gained some value)

[NetworkMan]

Spreadsheet? What’s wrong with a notebook and a pencil under the centre armrest? Mine goes back many years!

My father did that from the 1960's and I still do it.  Every few cars though, the new car gets a new notebook. as a treat.  Austin A55, Vauxhall Victor, Cortina 1.2 MK 1, Ford Escort 1.3, SAAB 96V4 all averaged about 30-35 mpg.  Starting with a Metro 1.0 and Micra 1.0 things got better with over 40 mpg and this trend continued with Rover 214 and Honda Civic 1.4.  GDi engine and Turbo in SEAT Ibiza 1.2 and VW Polo 1.4 moved up towards 47 mpg and now the Jazz looks to be more like 60 mpg.  You can see that fuel injection made a difference, then GDI/Turbo and now hybrid.

I record date, miles, litres bought and tank full(Y/N).  Every 2 or 3 tank fillups I calculate mpg for the 1000 miles or so and overall mpg since new.

[NetworkMan]

The latest Which annual car guide still rates the Jazz a best buy, but says the motorway test fuel consumption averaged only 39.2 mpg.  This seems unusually low as I assume they stuck to speed limits, but I don’t yet have enough personal motorway experience to comment.

Excuse me bringing this issue up but it is relevant to a complaint I have raised with Which.

I've been aware for some time that Which don't do much car testing themselves instead using the tests performed by the German AA equivalent ADAC which happen to be available for us to read at www.adac.de, with Google translate doing a good job using the Chrome browser.  If you read the Jazz review (you need the PDF download and can translate with Google translate) you will see their Autobahn test with the same result (divide into 282.5 to convert from L/100 km.).  This quote by Which is missleading because the ADAC test is done at a speed of 130 km/h with violent acceleration involved, and it penalises the Jazz because of the way economy falls off at high speeds. It is most certainly not representative of UK motorway driving.

What put me onto this in the first place was the luggage capacity figures which are always identical to the ADAC ones and different from the VDA ones often quoted.  Further clues come from the many photographs of "our tests" being performed which are on LHD  vehicles, sometimes with German number plates.

When I approached Which about this they did not deny it but said they provided input to the test procedures. I told them I thought they were missleading the public but the reply was  just evasive.

[Lord Voltermore]

And this is assuming the German testers even keep to 130 kph. (80 mph)  Autobahns have no speed limit by default  and prevailing traffic often drive much faster than 130 kph.  And the Jazz is still quiet and unstressed at 140 kph plus  (I should imagine    ) 

Also quite a few autobahns are outdated with only 2 lanes.  So even if testers keep to a maximum of 130 kph  they will often have to get out of the way of faster cars  and then  held up by 100kph trucks.  (been there, done that )  Repeatedly regaining 130 kph will use a lot more petrol .Especially if drivers are not paying for their own fuel or  its up one the steep climbs common on German motorways, . Indeed cruise control can be a bit manic when regaining lost speed if left to istelf  , although not as bad as it was on  pre facelift cars.     Not circumstances where Jazz mpg is at best.    But while 39.1 mpg is much less than expected from a mk4 Jazz its still not bad compared to some cars .

[John Ratsey]

There's no denying that the Jazz's mpg plummets at high speed but less than 40mpg indicates testing in unrepresentative conditions (excessive speed / a head wind / cold weather / very wet roads). The mpg for the Extra High WLTP test cycle (which includes substantial sections of 75mph / 120kmph) is nearer 50mpg than 40 https://www.honda.co.uk/cars/new/jazz-hybrid/specifications.html. Honda, unlike many manufacturers, do publish the results for different parts of the WLTP test and I reckon that Medium is nearest to my average driving.

Neither my car nor myself like motorway driving and when I do use them for lack of a convenient alternative then I tend to potter along at lorry speed which keeps the mpg at around 60 in fair weather. It's not designed to be a motorway cruiser with a body shape which prioritises internal space over aerodynamic efficiency and an engine sized to be most efficient in less power-demanding conditions.  Honda is aware of the problem and a recent announcement said "The new 1.5-liter engine will achieve a significant improvement in fuel economy by expanding the range where engine RPM becomes highly efficient in balance with engine torque, by more than 40% compared to the current 1.5-liter engine for the e:HEV system." https://global.honda/en/newsroom/news/2024/4241218aeng.html (I hope Honda will also address the problem of excessive cooling of the engine during the winter months).

Keep the Jazz in its comfort zone of 60mph or less on rural roads and the mpg can be impressive. I attach a screen shot of what my Jazz claimed for a 150 mile round trip in good weather last August. Deducting 5% optimism in the car's computer still leaves 76.8 mpg. The Mk 5, when it arrives, may not do much better. I always find the mpg is better on the first half of that trip as the destination is about 50m lower than home so the car has some gravity assistance on the outward trip and has to climb back uphill on the return.

[coldstart]

long story short: If you were looking for a "race car" or your main driving is on motorways (or even worse: the german autobahn) then I simply have to tell you, that you bought the wrong car (if fuel efficency was your main goal)!

The Honda e:HEV system truly thrives in urban traffic and shines during relaxed out of town traffic as well.
However, it was never designed for "sportiness" or fuel economy with speeds outside of it's "direct or engine drive" capabilities.

Sorry to keep repeating myself on this: Should you happen to be truly fuel conscious, try to avoid short trips with high demands on cabin heat during the cold season!

As you probably can tell by my signature and maybe some research on spritmonitor.de I'm quite "comfortable" (at least mpg-wise) with my own advice. (plus: The Jazz offers far superior mpg than my previous car!)

I only went for the Advance trim because it offered heated seats along with a heated steering wheel.