With CO2 emissions of just 92g/km, the Eco qualifies for the lowest band of company car tax available to diesel-powered cars, which means 40% rate taxpayers will save at least £220 a year compared with any other A-Class model.
This improved efficiency has been achieved by adding longer gearing, lowered suspension and a smaller fuel tank. Together, these things boost official fuel economy figures by 4.2mpg to 78.5mpg.
Here we’re testing the standard six-speed manual version, although an automatic is available for an extra £1275. This uses a larger diesel engine, though, so ups CO2 emissions to 102g/km.
What’s the Mercedes A180 CDI Eco like to drive?
The new A180 CDI Eco uses the same 1.5-litre diesel engine as the regular (and now defunct) A180 CDI. This isn’t a good thing, because it means there’s barely any pull below 1750rpm. The Eco’s longer gearing only serves to amplify the problem, forcing you to change down more often than you’d like.
Even when you keep the revs relatively high, the Mercedes is still noticeably more sluggish than rivals, including the Audi A3 Sportback 1.6 TDI and BMW 116d ED.
Worse still, the Merc’s engine is very noisy, and transmits too much vibration through the steering wheel and pedals. There’s also plenty of road and wind noise at a steady motorway cruise.
Despite the lowered suspension, our test car benefited from a slightly softer ride than we’ve experienced with other A-Class models, which could have been due to the winter tyres that were fitted. However, sharp-edged bumps and potholes still sent jolts through the cabin, so even in this form, the A-Class isn’t as comfortable as the best premium hatchbacks.
What’s more, the A180 CDI Eco doesn’t handle very well; it responds in a lethargic manner to steering inputs, and there’s also too much lean through corners. It’s a shame, because the steering is nicely weighted.
What’s the 2014 Mercedes A180 CDI Eco like inside?
There are no changes here, so the dashboard remains smartly styled, with heater vents similar to those in the SLS supercar.
However, the materials aren't as classy as those in an Audi A3, and the screen at the top of the dashboard looks too much like an aftermarket portable navigation system.
You operate most of the A-Class's infotainment functions by scrolling through menus on this screen – something that can be a little distracting to do while driving due to the complicated menus.
Interior space is more impressive; four six-footers will be comfortable and a fifth can squeeze in for short journeys. You just have to be careful not to bump your head when getting into the back due to the swooping roofline.
The boot, meanwhile, is a reasonable size, but it's quite shallow, and the narrow opening makes it tricky to load bulky items.
The Eco is available only in entry-level SE trim, which means you get 16-inch alloys, air-conditioning, four electric windows, a multi-function steering wheel, Bluetooth and a USB socket.
Should I buy one?
The A180 CDI Eco certainly gives the A-Class added appeal with company car drivers, because it’s cheaper to run than existing models in the range and no worse to drive.
However, due to the comparatively high list price, the Eco works out barely any cheaper to run as a company car than either an Audi A3 Sportback 1.6 TDI or a BMW 116d ED.
When you consider that both of these rivals are more practical, more refined and significantly better to drive, we’d suggest you think carefully before choosing the Mercedes.
What Car? says...
Mercedes-Benz A180 CDI Eco
Engine size 1.5-litre diesel
Price from £21,965
Torque 191lb ft
0-62mph 11.3 seconds
Top speed 118mph
Fuel economy 78.5mpg