ECOnetic is Ford's way of expressing what, for example, BlueMotion means to Volkswagen and Ecomotive to SEAT. Take a car you already build, give it a few tweaks, add an extra environmentally-friendly sounding word to its name and promote it as a low-CO2 special.In the case of the Focus ECOnetic, the tweaks in question will not be unfamiliar to those of you who have been following this recent trend. There are no changes to the engine ECU or to the gearing, as there often are, but Ford has followed conventional practice by reducing the ride height and adding an aerodynamics kit to improve airflow, and fitting low rolling resistance tyres. In a less common move, the ECOnetic also has lighter than normal transmission oil, developed by BP, to give the engine less work to do in pushing the gears around.The engine Ford has used for this car is the 1.6-litre TDCi turbo diesel, in 109bhp form and with a particulate filter as tested here, or producing 89bhp and without the filter. Available body styles are five-door hatchback or estate.Despite these differences, all four versions have the same official combined fuel economy of 65.6mpg, and CO2 emissions of either 114g/km or 115g/km. Either way, annual VED is £35 per year, rather than the £120 which would be the case if the ECOnetic produced more than 120g/km.Sounding good so far, isn't it? Yes, I thought so too. But there are a couple of points which make this apparently worthy project seem slightly questionable.The first is that the figures I've mentioned are not dramatically better than those achieved by a regular Focus 1.6 TDCi. The standard model has combined fuel economy of 62.7mpg on the EU cycle, which is so close to the ECOnetic's performance as to be hardly worth bothering about, and it is also a sub-120g/km car, so you still pay £35 a year in road tax. As far as the Chancellor is concerned, it doesn't matter which one you buy because he's not going to see a difference in income.The other point is that 65.6mpg bears absolutely no resemblance to my experience of how much diesel the ECOnetic uses. On the last day of this test I had to make a quick run over a fast but very hilly A-road, and of course that dropped the average a bit, but before I did so the trip computer was telling me that I was averaging a little more than 53mpg.Previous experience of Ford trip computers suggests that they over-read by around 1mpg, so let's call that 52mpg, achieved by not being particularly careful about economy but also not pushing the car hard. Normal everyday motoring, I'd say, though with very little city driving to bring the average down.Frankly I was okay with this, because I can happily live with a car that's going to get me more than 50 miles for every gallon without me giving the matter much consideration. But I would have to concentrate hard to reach 65.6.mpg, and although (like most people) I don't usually match the official combined figure, it came as a surprise that I strayed so far from it in this case.Another aspect worth mentioning is that the ECOnetic has its own trim level, and is priced midway through the Focus range between Style and Zetec. It is not, therefore, an unusually cheap car. If you didn't object to having less equipment and slightly inferior performance (the latter perhaps being low on the list of priorities for buyers of a car like this) you could have a 1.6 TDCi Studio five-door for £2200 less than Ford charges for the car tested here.There is no way you're going to get anything remotely near that money back on fuel bills by buying an ECOnetic instead, the VED situation is identical, and the official difference in CO2 emissions is both marginal and almost certainly not reflective of the true situation. I enjoyed spending time with the ECOnetic - it's a quiet, comfortable car, practical enough for the job and pleasant to drive - but I can't see a reason to recommend it any more than I would several other models in the Focus range. Engine 1560 cc, 4 cylinders Power 110 bhp @4000 rpm Torque 177 ib/ft @1750 rpm Transmission 5 speed manual Fuel/CO2 65.6 mpg / 115 g/km Acceleration 0-62mph: 10.9sec Top speed 119 mph Price From £16816.00 approx Release date 01/01/2008