Vauxhall Astra EcoFlex

Several models in Vauxhall’s Astra range dip below 100g/km, and all use the same 1.7-litre CDTi diesel engine. The engine comes in two slightly different states of tune. One develops 110PS and the other 130PS, and despite the difference in power output both have the same 99g/km official CO2 rating and 76.3mpg combined cycle fuel-economy score. Both versions feature automatic stop-start to help achieve these figures.

The more powerful option also brings more torque – 300Nm rather than 260Nm – helping to make the Astra quicker to 62mph at 10.4 seconds rather than 11.8 seconds. There is also a price difference, of course. New, the beefier EcoFlex Astra costs from £20,005, the weedier edition £19,380.

There are also various Vauxhall trim levels to consider, with both editions of the 99g/km engine available in ES, Exclusiv, Tech Line, SE and SRi formats, with prices before options reaching as high as £23,175. Note that some EcoFlex cars fitted with wider wheels have CO2 ratings of 110g/km. So it’s worth delving beyond the EcoFlex badge on the boot.

Searching for the swifter 130PS editions through Vauxhall’s Network Q scheme turned up some promising second-hand candidates. Budget around £15,000 for a low-mileage, year-old model in plush SE or sporty SRi trim, or a thousand or so less for Exclusiv or ES trim. Looking beyond the approved-used scheme will save a little more. A search for a nearly new Vauxhall Astra at Motorpoint turned up a year-old, 14,000-mile SE with 99g/km and 130PS for £11,599. Temptingly, that’s about half the price of a new example.

Ford Focus Econetic

Ford’s Focus range dips to an impressively low 88g/km at present, but to limbo so low requires a hair-shirt experience in uninspiring Edge trim. Aim for a still frugal 99g/km and there are a couple of much more satisfying options in the Focus range – the 1.6 TDI Econetic in either Zetec or Titanium trim.

The 1.6-litre turbodiesel engine provides 105PS and 270Nm, enough to arrive at 62mph in 11.8 seconds. Both Econetic models are fitted with a manual 6-speed gearbox and score 76.4mpg in the combined cycle test.

Opting for the Zetec trim brings alloys, Bluetooth, a DAB stereo and heated windscreen. Titanium gains convenience features like auto lights and wipers, climate control and improved interior materials.

New, the Zetec costs from £19,145 before options, while the Titanium is pricier at £20,395. Shop nearly new and you can expect to shave off a tidy sum. A budget of £15,000 ought to be enough to find a good one-year-old Titanium Econetic through Ford’s approved-used scheme, while £13,800 should bring in a nearly-new Zetec Econetic.

Honda Civic 1.6 i-DTEC

Slightly less obvious than the Ford or Vauxhall, the Honda Civic nonetheless offers a practical family car with sub-100g/km emissions, at a price that won’t leave you gasping.

The engine to plump for is the 1.6 i-DTEC diesel, which achieves a CO2 score of 94g/km and official combined-cycle economy of 78.5mpg. With peak power of 120PS and 300Nm of torque at its disposal, this engine can whip the Civic to 62mph in a swift 10.5 seconds.

Honda offers five trim levels with this engine and CO2 output – SE, SE-T, ES, ES-T and EX, with base prices running from £19,575 through to £23,585. The “T” in the trim names refers to built-in navigation with hands-free Bluetooth phone facilities. ES is pretty extensively equipped with reversing camera, auto lights and wipers, split climate control and leather on the wheel and gearstick. Leather upholstery, plus upgraded audio and navigation are the main benefits of the top EX spec.

The 94g/km Civic first arrived in the UK in December 2012, so used examples are currently no more than six months old, meaning it’s a little early for real bargains. Prices for the 1.6 i-DTEC Civic within Honda’s approved-used scheme start at £15,000 for the base SE spec, around £17,000 should land an ES, while £18,000 is currently the entry price for a used EX edition.